@article{cecala_watershed_2025,
	title = {Do watershed conditions or local climate play a larger role in determining regional stream salamander distributions?},
	issn = {0018-8158, 1573-5117},
	url = {https://link.springer.com/10.1007/s10750-025-05848-8},
	doi = {10.1007/s10750-025-05848-8},
	abstract = {Anthropogenic influences like land use and climate variability interact with natural heterogeneity to influence the persistence of stream salamanders. Using occupancy modeling in the southern Appalachian Mountains, we investigated the influence of land use, climate, and physical context (e.g., drainage area, elevation) on stream salamander occupancy, noting species, and life stage specific responses. Our results illustrate that forest loss is a better predictor of salamander occupancy than physical context (elevation) or climate. Across the gradients in this dataset, precipitation did not have a significant influence on salamander occupancy, potentially due to the observed narrow, wet gradient. Temperature had little effect on Eurycea wilderae occupancy; however, temperature negatively affected adult but not larval Desmognathus amphileucus occupancy. Spatial thermal variability in this study was larger than projected increases due to climate change, suggesting that local mechanisms (e.g., behavior or physiological plasticity) may facilitate salamander resilience to climate change. However, the negative effects of forest loss coupled with rising temperatures (e.g., increased solar radiation, warmer stream runoff) underscore the importance of riparian forests in mitigating climate stressors. Preserving forest cover is critical for maintaining stream salamander populations and may offer opportunities for maintaining resilience in the face of additional stressors like rising temperatures or drought.},
	language = {en},
	urldate = {2025-06-14},
	journal = {Hydrobiologia},
	author = {Cecala, Kristen K. and Halstead, Brian J. and McGrory, James S. and Maerz, John C.},
	month = mar,
	year = {2025},
}

Anthropogenic influences like land use and climate variability interact with natural heterogeneity to influence the persistence of stream salamanders. Using occupancy modeling in the southern Appalachian Mountains, we investigated the influence of land use, climate, and physical context (e.g., drainage area, elevation) on stream salamander occupancy, noting species, and life stage specific responses. Our results illustrate that forest loss is a better predictor of salamander occupancy than physical context (elevation) or climate. Across the gradients in this dataset, precipitation did not have a significant influence on salamander occupancy, potentially due to the observed narrow, wet gradient. Temperature had little effect on Eurycea wilderae occupancy; however, temperature negatively affected adult but not larval Desmognathus amphileucus occupancy. Spatial thermal variability in this study was larger than projected increases due to climate change, suggesting that local mechanisms (e.g., behavior or physiological plasticity) may facilitate salamander resilience to climate change. However, the negative effects of forest loss coupled with rising temperatures (e.g., increased solar radiation, warmer stream runoff) underscore the importance of riparian forests in mitigating climate stressors. Preserving forest cover is critical for maintaining stream salamander populations and may offer opportunities for maintaining resilience in the face of additional stressors like rising temperatures or drought.

@article{bradke_potential_2025,
	title = {Potential and {Limitations} of {Unmarked} {Population} {Surveys} to {Inform} {State}-{Wide} {Management} for {Diamondback} {Terrapins}},
	issn = {1071-8443},
	url = {https://doi.org/10.2744/CCB-1623.1},
	doi = {10.2744/CCB-1623.1},
	abstract = {Diamondback terrapins (Malaclemys terrapin) are challenging to monitor in their salt marsh habitat. However, large-scale monitoring is needed to understand the status of populations and effectively apply targeted management. The Georgia Department of Natural Resources (GA DNR) is interested in developing a long-term monitoring program that it can use for tracking relative levels of terrapin abundance among creeks throughout the state to trigger varying intensities of management actions. The objective of this study was to investigate the potential of repeated head counts and binomial N-mixture models to inform the GA DNR’s state-wide monitoring and management objectives. We used the unmarked repeated count method to categorize sites into 3 levels of relative abundance while accounting for uncertainty in estimates. However, relative abundance estimates were sensitive to the timing of sampling within the active season and location of sampling along the creek, indicating limitations of this method. Results also showed that as survey effort increased, the number of sites that could be confidently assigned to higher abundance categories also increased. Therefore, if an objective is to minimize the number of creeks requiring more intensive and potentially more restrictive management actions, a high level of survey effort is recommended. Because relative abundance estimates using head count methods varied with timing and location of sampling, survey methods would need to be standardized and consistent across years. If applied judiciously, a method using head count surveys and N-mixture models may be the most effective means of state- or region-wide monitoring of terrapins across large numbers of sites. Additionally, if integrated with ongoing, long-term capture–recapture studies at a smaller number of sites, the capacity for head count surveys to inform terrapin management decisions across large areas and many sites could be enhanced.},
	urldate = {2025-06-14},
	journal = {Chelonian Conservation and Biology},
	author = {Bradke, Danielle R. and Dodd, Mark G. and Maerz, John C.},
	month = may,
	year = {2025},
}

Diamondback terrapins (Malaclemys terrapin) are challenging to monitor in their salt marsh habitat. However, large-scale monitoring is needed to understand the status of populations and effectively apply targeted management. The Georgia Department of Natural Resources (GA DNR) is interested in developing a long-term monitoring program that it can use for tracking relative levels of terrapin abundance among creeks throughout the state to trigger varying intensities of management actions. The objective of this study was to investigate the potential of repeated head counts and binomial N-mixture models to inform the GA DNR’s state-wide monitoring and management objectives. We used the unmarked repeated count method to categorize sites into 3 levels of relative abundance while accounting for uncertainty in estimates. However, relative abundance estimates were sensitive to the timing of sampling within the active season and location of sampling along the creek, indicating limitations of this method. Results also showed that as survey effort increased, the number of sites that could be confidently assigned to higher abundance categories also increased. Therefore, if an objective is to minimize the number of creeks requiring more intensive and potentially more restrictive management actions, a high level of survey effort is recommended. Because relative abundance estimates using head count methods varied with timing and location of sampling, survey methods would need to be standardized and consistent across years. If applied judiciously, a method using head count surveys and N-mixture models may be the most effective means of state- or region-wide monitoring of terrapins across large numbers of sites. Additionally, if integrated with ongoing, long-term capture–recapture studies at a smaller number of sites, the capacity for head count surveys to inform terrapin management decisions across large areas and many sites could be enhanced.

@article{marshall_gopher_2024,
	title = {Gopher {Tortoise} ({Gopherus} polyphemus) {Vertebrate} {Burrow} {Commensals} within a {Private}, {Working} {Forest} {Landscape}},
	volume = {112},
	issn = {2766-1512},
	url = {https://bioone.org/journals/ichthyology-and-herpetology/volume-112/issue-2/h2021120/Gopher-Tortoise-Gopherus-polyphemus-Vertebrate-Burrow-Commensals-within-a-Private/10.1643/h2021120.full},
	doi = {10.1643/h2021120},
	abstract = {The Gopher Tortoise (Gopherus polyphemus) is a keystone species endemic to the Coastal Plain ecoregion of the southeastern United States. Gopher Tortoises excavate extensive burrows that are used by over 60 vertebrate and 300 invertebrate species. Our understanding of burrow commensals has generally been limited to Longleaf Pine (Pinus palustris) savanna and xeric uplands and shrublands, excluding private, working pine (Pinus spp.) forests that are known to harbor tortoise populations. Therefore, we used passive infrared wildlife cameras to document vertebrate burrow commensals and evaluate differences in composition across burrow classifications (i.e., abandoned, active, and inactive) within a private, working Loblolly Pine (Pinus taeda) forest located in the Upper Coastal Plain ecoregion of Georgia, USA. Our study showed that the composition of vertebrate commensals did not differ across abandoned, active, or inactive tortoise burrows, indicating that burrows, regardless of classification, may provide a similar suite of resources (e.g., refugia, forage) to vertebrate commensals. Also, we observed numerous species using burrows that typically occur in other landscapes with known tortoise populations (e.g., Longleaf Pine savannah). We encourage continued monitoring of tortoise burrows and other potential refugia within working forests to better understand how these structures contribute to species abundance and persistence within these forests.},
	language = {en},
	number = {2},
	urldate = {2025-01-21},
	journal = {Ichthyology \& Herpetology},
	author = {Marshall, Craig D. and Maerz, John C. and Larsen-Gray, Angela L. and Martin, James A.},
	month = jun,
	year = {2024},
}

The Gopher Tortoise (Gopherus polyphemus) is a keystone species endemic to the Coastal Plain ecoregion of the southeastern United States. Gopher Tortoises excavate extensive burrows that are used by over 60 vertebrate and 300 invertebrate species. Our understanding of burrow commensals has generally been limited to Longleaf Pine (Pinus palustris) savanna and xeric uplands and shrublands, excluding private, working pine (Pinus spp.) forests that are known to harbor tortoise populations. Therefore, we used passive infrared wildlife cameras to document vertebrate burrow commensals and evaluate differences in composition across burrow classifications (i.e., abandoned, active, and inactive) within a private, working Loblolly Pine (Pinus taeda) forest located in the Upper Coastal Plain ecoregion of Georgia, USA. Our study showed that the composition of vertebrate commensals did not differ across abandoned, active, or inactive tortoise burrows, indicating that burrows, regardless of classification, may provide a similar suite of resources (e.g., refugia, forage) to vertebrate commensals. Also, we observed numerous species using burrows that typically occur in other landscapes with known tortoise populations (e.g., Longleaf Pine savannah). We encourage continued monitoring of tortoise burrows and other potential refugia within working forests to better understand how these structures contribute to species abundance and persistence within these forests.

@article{hutcheson_origin_2024,
	title = {The {Origin} and {Ecology} of a {Likely} {Introduced} {Population} of {Southern} {Black}-{Bellied} {Salamanders} ({Desmognathus} amphileucus)},
	volume = {23},
	issn = {1528-7092},
	url = {https://bioone.org/journals/southeastern-naturalist/volume-23/issue-1/058.023.0103/The-Origin-and-Ecology-of-a-Likely-Introduced-Population-of/10.1656/058.023.0103.full},
	doi = {10.1656/058.023.0103},
	abstract = {Characterizing the origin and ecology of introduced species is important for developing management plans. We discovered an isolated population of black-bellied salamanders (Desmognathus sp.) in the Piedmont of Georgia, 30 km southwest of their known range. We used phylogenetic methods to confirm the salamanders were D. amphileucus (Southern Black-Bellied Salamander), with their closest relatives in the Blue Ridge. We observed all life stages and used mark–recapture methods to estimate a population size of 39 post-metamorphic individuals. We used gastric lavage to document prey items novel in diet studies of black-bellied salamanders but reported previously in other Desmognathus. We hypothesize this population was likely introduced via the bait trade, has grown since introduction, and is consuming resources used by native salamanders.},
	language = {en},
	number = {1},
	urldate = {2025-01-21},
	journal = {Southeastern Naturalist},
	author = {Hutcheson, Kevin G. and Pierson, Todd W. and Maerz, John C.},
	month = feb,
	year = {2024},
}

Characterizing the origin and ecology of introduced species is important for developing management plans. We discovered an isolated population of black-bellied salamanders (Desmognathus sp.) in the Piedmont of Georgia, 30 km southwest of their known range. We used phylogenetic methods to confirm the salamanders were D. amphileucus (Southern Black-Bellied Salamander), with their closest relatives in the Blue Ridge. We observed all life stages and used mark–recapture methods to estimate a population size of 39 post-metamorphic individuals. We used gastric lavage to document prey items novel in diet studies of black-bellied salamanders but reported previously in other Desmognathus. We hypothesize this population was likely introduced via the bait trade, has grown since introduction, and is consuming resources used by native salamanders.

@article{burrow_estimating_2023,
	title = {Estimating the potential drivers of dispersal outcomes for juvenile gopher frogs ({Rana} capito) using agent-based models},
	volume = {accepted},
	url = {https://www.frontiersin.org/articles/10.3389/fevo.2023.1026541/full},
	doi = {https://doi.org/10.3389/fevo.2023.1026541},
	abstract = {Among mobile terrestrial animals, movement among microsites can allow individuals to behaviorally moderate their body temperatures and rates of water loss, which can have important consequences for activity times, growth, fecundity, and survival. Ground-layer vegetation can change the availability and variability of microclimates; however, gaps in our understanding of how individuals interact with the microclimates created by vegetation limit our ability to inform management actions for wildlife. Amphibians can simultaneously balance operant body temperatures and water loss and the availability of heterogeneous microclimates should moderate how effectively they are able to do so. However, relatively few studies have attempted to mechanistically demonstrate how ground vegetationdriven effects on microclimatic variation may affect amphibian performance and survival. Agent-based modeling (ABM) can incorporate behavior and other mechanisms to understand how animals interact with their environments to result in larger scale patterns. They are effective for exploring alternative scenarios and representing the uncertainty in systems. Here, we use ABMs to integrate field and laboratory measurements of movement behavior, physiology, and plant effects on near-ground microclimate to explore how ground vegetation and the availability of terrestrial refugia may affect the survival and terrestrial distributions of juvenile gopher frogs (Rana capito) under two weather regimes. We  also examine how assumptions regarding micro-scale movement ({\textless} 1m2) affect the influence of ground vegetation on survival and settlement within refugia. While all variables affected settlement and survival, our models predict that inter-annual variation in weather and the density and spatial distribution of permanent refugia likely have the greatest influence on juvenile survival. The benefit of increased ground vegetation was dependent on the reasonable assumption that gopher frogs exhibit microclimate habitat selection throughout the day and night to limit water loss. Our models suggest that vegetation would be most beneficial to amphibians under warmer weather regimes provided there is sufficient rainfall.},
	journal = {Frontiers in Ecology and the Environment},
	author = {Burrow, Angela K. and McEntire, Kira D. and Maerz, John C.},
	year = {2023},
}

Among mobile terrestrial animals, movement among microsites can allow individuals to behaviorally moderate their body temperatures and rates of water loss, which can have important consequences for activity times, growth, fecundity, and survival. Ground-layer vegetation can change the availability and variability of microclimates; however, gaps in our understanding of how individuals interact with the microclimates created by vegetation limit our ability to inform management actions for wildlife. Amphibians can simultaneously balance operant body temperatures and water loss and the availability of heterogeneous microclimates should moderate how effectively they are able to do so. However, relatively few studies have attempted to mechanistically demonstrate how ground vegetationdriven effects on microclimatic variation may affect amphibian performance and survival. Agent-based modeling (ABM) can incorporate behavior and other mechanisms to understand how animals interact with their environments to result in larger scale patterns. They are effective for exploring alternative scenarios and representing the uncertainty in systems. Here, we use ABMs to integrate field and laboratory measurements of movement behavior, physiology, and plant effects on near-ground microclimate to explore how ground vegetation and the availability of terrestrial refugia may affect the survival and terrestrial distributions of juvenile gopher frogs (Rana capito) under two weather regimes. We  also examine how assumptions regarding micro-scale movement (\textless 1m2) affect the influence of ground vegetation on survival and settlement within refugia. While all variables affected settlement and survival, our models predict that inter-annual variation in weather and the density and spatial distribution of permanent refugia likely have the greatest influence on juvenile survival. The benefit of increased ground vegetation was dependent on the reasonable assumption that gopher frogs exhibit microclimate habitat selection throughout the day and night to limit water loss. Our models suggest that vegetation would be most beneficial to amphibians under warmer weather regimes provided there is sufficient rainfall.

@article{campbell_grant_priority_2023,
	title = {Priority research needs to inform amphibian conservation in the {Anthropocene}},
	copyright = {All rights reserved},
	issn = {2578-4854, 2578-4854},
	url = {https://conbio.onlinelibrary.wiley.com/doi/10.1111/csp2.12988},
	doi = {10.1111/csp2.12988},
	abstract = {The problem of global amphibian declines has prompted extensive research over the last three decades. Initially, the focus was on identifying and characterizing the extent of the problem, but more recently efforts have shifted to evidence-based research designed to identify best solutions and to improve conservation outcomes. Despite extensive accumulation of knowledge on amphibian declines, there remain knowledge gaps and disconnects between science and action that hamper our ability to advance conservation efforts. Using input from participants at the ninth World Congress of Herpetology, a U.S. Geological Survey Powell Center symposium, amphibian on-line forums for discussion, the International Union for Conservation of Nature Assisted Reproductive Technologies and Gamete Biobanking group, and respondents to a survey, we developed a list of 25 priority research questions for amphibian conservation at this stage of the Anthropocene. We identified amphibian conservation research priorities while accounting for expected tradeoffs in geographic scope, costs, and the taxonomic breadth of research needs. We aimed to solicit views from individuals rather than organizations while acknowledging inequities in participation. Emerging research priorities (i.e., those underrepresented in recently published amphibian conservation literature) were identified, and included the effects of climate change, community-level (rather than single species-level) drivers of declines, methodological improvements for research and monitoring, genomics, and effects of land-use change. Improved inclusion of under-represented members of the amphibian conservation community was also identified as a priority. These research needs represent critical knowledge gaps for amphibian conservation although filling these gaps may not be necessary for many conservation actions.},
	language = {en},
	urldate = {2023-08-02},
	journal = {Conservation Science and Practice},
	author = {Campbell Grant, Evan H. and Amburgey, Staci M. and Gratwicke, Brian and Chaves, Victor Acosta and Belasen, Anat M. and Bickford, David and Brühl, Carsten A. and Calatayud, Natalie E. and Clemann, Nick and Clulow, Simon and Crnobrnja‐Isailovic, Jelka and Dawson, Jeff and De Angelis, David A. and Dodd, C. Kenneth and Evans, Annette and Ficetola, Gentile Francesco and Falaschi, Mattia and González‐Mollinedo, Sergio and Green, David M. and Gamlen‐Greene, Roseanna and Griffiths, Richard A. and Halstead, Brian J. and Hassapakis, Craig and Heard, Geoffrey and Karlsson, Catharina and Kirschey, Tom and Klocke, Blake and Kosch, Tiffany A. and Novaes, Sophia Kusterko and Linhoff, Luke and Maerz, John C. and Mosher, Brittany A. and O'Donnell, Katherine and Ochoa‐Ochoa, Leticia M. and Olson, Deanna H. and Ovaska, Kristiina and Roberts, J. Dale and Silla, Aimee J. and Stark, Tariq and Tarrant, Jeanne and Upton, R. and Vörös, Judit and Muths, Erin},
	month = jul,
	year = {2023},
	pages = {e12988},
}

The problem of global amphibian declines has prompted extensive research over the last three decades. Initially, the focus was on identifying and characterizing the extent of the problem, but more recently efforts have shifted to evidence-based research designed to identify best solutions and to improve conservation outcomes. Despite extensive accumulation of knowledge on amphibian declines, there remain knowledge gaps and disconnects between science and action that hamper our ability to advance conservation efforts. Using input from participants at the ninth World Congress of Herpetology, a U.S. Geological Survey Powell Center symposium, amphibian on-line forums for discussion, the International Union for Conservation of Nature Assisted Reproductive Technologies and Gamete Biobanking group, and respondents to a survey, we developed a list of 25 priority research questions for amphibian conservation at this stage of the Anthropocene. We identified amphibian conservation research priorities while accounting for expected tradeoffs in geographic scope, costs, and the taxonomic breadth of research needs. We aimed to solicit views from individuals rather than organizations while acknowledging inequities in participation. Emerging research priorities (i.e., those underrepresented in recently published amphibian conservation literature) were identified, and included the effects of climate change, community-level (rather than single species-level) drivers of declines, methodological improvements for research and monitoring, genomics, and effects of land-use change. Improved inclusion of under-represented members of the amphibian conservation community was also identified as a priority. These research needs represent critical knowledge gaps for amphibian conservation although filling these gaps may not be necessary for many conservation actions.

@article{marshall_using_2023,
	title = {Using ancillary data to model the terrestrial distribution of gopher frogs},
	volume = {2023},
	copyright = {All rights reserved},
	url = {https://doi.org/10.1002/jwmg.22397},
	doi = {DOI: 10.1002/jwmg.22397},
	abstract = {An inherent challenge in managing rare or cryptic species is data deficiency. For this reason, ancillary data is a potentially valuable resource for generating key population estimates for priority species. We compiled ancillary commensal data collected between 1982 and 2020 during surveys of gopher tortoise (Gopherus polyphemus)burrows to estimate the terrestrial distribution of gopher frogs (Rana capito) from potential breeding wetlands. Gopher frogs were detected in gopher tortoise burrows 30‒3,879 m from identified wetlands. A global model of all records from all sites indicated that the probability of a gopher frog residing in a gopher tortoise burrow declined with increasing distance from a wetland. This pattern also held for 4 of 5 sites with a sufficient number of gopher frog detections to model independently. Based on the full data set, we estimated that 50\%, 90\%, and 99\% of gopher frog observations occurred within 392 m, 1,019 m, and 2,752 m of the nearest wetland, respectively. Our results indicate a higher proportion of gopher frogs emigrate longer distances from wetlands than was previously reported using other methods, such as radio‐telemetry. This information can directly assist with management decisions, notably the spatial extent for application of habitat management surrounding breeding wetlands. More generally, this study illustrates the capacity of ancillary data to fill data deficiencies for a rare and cryptic species and highlights the importance of these data.},
	language = {en},
	journal = {Journal of Wildlife Management},
	author = {Marshall, Craig D and Crawford, Brian A and Smith, Lora L and Enge, Kevin M and Elliott, Matt and McGuire, Savannah and Maerz, John C},
	year = {2023},
	pages = {e22397},
}

An inherent challenge in managing rare or cryptic species is data deficiency. For this reason, ancillary data is a potentially valuable resource for generating key population estimates for priority species. We compiled ancillary commensal data collected between 1982 and 2020 during surveys of gopher tortoise (Gopherus polyphemus)burrows to estimate the terrestrial distribution of gopher frogs (Rana capito) from potential breeding wetlands. Gopher frogs were detected in gopher tortoise burrows 30‒3,879 m from identified wetlands. A global model of all records from all sites indicated that the probability of a gopher frog residing in a gopher tortoise burrow declined with increasing distance from a wetland. This pattern also held for 4 of 5 sites with a sufficient number of gopher frog detections to model independently. Based on the full data set, we estimated that 50%, 90%, and 99% of gopher frog observations occurred within 392 m, 1,019 m, and 2,752 m of the nearest wetland, respectively. Our results indicate a higher proportion of gopher frogs emigrate longer distances from wetlands than was previously reported using other methods, such as radio‐telemetry. This information can directly assist with management decisions, notably the spatial extent for application of habitat management surrounding breeding wetlands. More generally, this study illustrates the capacity of ancillary data to fill data deficiencies for a rare and cryptic species and highlights the importance of these data.

@article{terrell_breeding_2023,
	title = {Breeding {Population} {Dynamics} of {Threatened} {Crawfish} {Frogs} {Inform} {Targets} for {Habitat} {Management}},
	volume = {111},
	issn = {2766-1512},
	url = {https://bioone.org/journals/ichthyology-and-herpetology/volume-111/issue-1/h2022031/Breeding-Population-Dynamics-of-Threatened-Crawfish-Frogs-Inform-Targets-for/10.1643/h2022031.full},
	doi = {10.1643/h2022031},
	abstract = {We used data from a five-year study at two focal breeding wetlands of a single Crawfish Frog (Rana areolata) population to demonstrate the relative importance and potential of tadpole survival as a target for population management. We concurrently estimated 11 vital rates in the field and used a females-only matrix projection model to estimate elasticities of demographic rates. We then simulated stochastic population dynamics at each wetland with and without immigration to estimate the intrinsic capacity for each focal breeding wetland to sustain a Crawfish Frog breeding population and the likelihood of breeding population persistence at each wetland. Elasticity of tadpole survival was second only to juvenile survival elasticity and 1.34–2.04 times greater than adult survival elasticity. Projections indicated that the Crawfish Frog population was not at risk of extinction but only one breeding site was capable of self-sustaining a breeding population. Because of low tadpole survival, the other breeding site was completely dependent on immigration to persist and was functioning as a population sink. Despite higher variability compared to terrestrial vital rates, larval survival did have a strong effect on population growth. Tadpole survival at the more productive breeding site was density dependent and likely related to wetland vegetation and predator and competitor abundance. Two additional findings were that annual survival of frogs following their first known breeding event was 48\% lower compared to survival of frogs that had bred in two or more prior years, and adult temporary emigration from the breeding population was moderately high. Our study demonstrates the benefits of using population models that integrate density-dependent processes, temporary emigration from the breeding population, and state-specific adult survival, to identify larval habitats that function as population sinks and limit current population size and persistence probability. We contend that tadpole survival is an important and feasible habitat management target within broader conservation strategies for Crawfish Frogs and other amphibian species.},
	language = {en},
	number = {1},
	urldate = {2023-02-22},
	journal = {Ichthyology \& Herpetology},
	author = {Terrell, Vanessa C. K. and Maerz, John C. and Engbrecht, Nathan J. and Stiles, Rochelle M. and Crawford, Brian A. and Lannoo, Michael J.},
	month = feb,
	year = {2023},
	pages = {72--86},
}

We used data from a five-year study at two focal breeding wetlands of a single Crawfish Frog (Rana areolata) population to demonstrate the relative importance and potential of tadpole survival as a target for population management. We concurrently estimated 11 vital rates in the field and used a females-only matrix projection model to estimate elasticities of demographic rates. We then simulated stochastic population dynamics at each wetland with and without immigration to estimate the intrinsic capacity for each focal breeding wetland to sustain a Crawfish Frog breeding population and the likelihood of breeding population persistence at each wetland. Elasticity of tadpole survival was second only to juvenile survival elasticity and 1.34–2.04 times greater than adult survival elasticity. Projections indicated that the Crawfish Frog population was not at risk of extinction but only one breeding site was capable of self-sustaining a breeding population. Because of low tadpole survival, the other breeding site was completely dependent on immigration to persist and was functioning as a population sink. Despite higher variability compared to terrestrial vital rates, larval survival did have a strong effect on population growth. Tadpole survival at the more productive breeding site was density dependent and likely related to wetland vegetation and predator and competitor abundance. Two additional findings were that annual survival of frogs following their first known breeding event was 48% lower compared to survival of frogs that had bred in two or more prior years, and adult temporary emigration from the breeding population was moderately high. Our study demonstrates the benefits of using population models that integrate density-dependent processes, temporary emigration from the breeding population, and state-specific adult survival, to identify larval habitats that function as population sinks and limit current population size and persistence probability. We contend that tadpole survival is an important and feasible habitat management target within broader conservation strategies for Crawfish Frogs and other amphibian species.

@article{brown_estimating_2023,
	title = {Estimating the effectiveness of using wildlife cameras versus visual-encounter surveys to detect herpetofauna},
	volume = {51},
	issn = {1035-3712, 1448-5494},
	url = {https://www.publish.csiro.au/WR/WR23037},
	doi = {10.1071/WR23037},
	abstract = {Context. Efficient monitoring of herpetofauna can prove challenging to agencies and NGOs responsible for their management. Wildlife cameras have been proposed as a method to monitor herpetofauna; however, estimates of detection rates and factors affecting detection by cameras are generally lacking and therefore limiting their application. Aims. We determined the effect of body size and temperature differential on the detection of snakes and frogs by passive infrared (PIR) wildlife cameras. We hypothesised that detection would differ among models and be positively correlated with body size and surface-temperature differential between the animal and substrate. We then conducted a field study to compare the detection of herpetofauna by a traditional method with PIR cameras. Methods. We tested 10 cameras of seven models on five snakes and one camera on six frogs. Photographs were downloaded to determine the detection rate of each species by each camera. We then chose a camera model to compare two herpetofauna survey methods, namely, drift fences equipped with cameras and visualencounter surveys. Surveys were conducted monthly over 12 months in Irwin County, GA, USA. Key results. The highest mean detection rates of snakes were 0.65 (s.e. = 0.33), 0.50 (s.e. = 0.34), and 0.49 (s.e. = 0.34) for the Browning Dark Ops, Reconyx Hyperfire 2, and Mossy Oak Covert Scouting Camera respectively. The detectability of larger snakes was greater than that of smaller snakes and increased as the absolute temperature differences between the snake and the substrate increased. The detectability of frogs was influenced by absolute temperature differential alone. PIR cameras generated five times more observations, documented more herpetofauna species, and were seven times more efficient than traditional surveys. Conclusions. The effectiveness of PIR cameras to detect herpetofauna varies among models and depends on the likelihood that the animal will have a body temperature significantly different from the temperature of the substrate. PIR cameras generated observations far more efficiently than traditional sampling methods. Implications. PIR wildlife cameras may be most effective at detecting larger, diurnal herpetofauna and least effective at detecting smaller, nocturnal species. Wildlife cameras have the potential to efficiently monitor some herpetofauna, providing a means to better evaluate management objectives.},
	language = {en},
	number = {1},
	urldate = {2024-01-12},
	journal = {Wildlife Research},
	author = {Brown, Ally K. and Hannon, Devyn A. and Maerz, John C.},
	editor = {Dundas, Shannon},
	month = oct,
	year = {2023},
	pages = {WR23037},
}

Context. Efficient monitoring of herpetofauna can prove challenging to agencies and NGOs responsible for their management. Wildlife cameras have been proposed as a method to monitor herpetofauna; however, estimates of detection rates and factors affecting detection by cameras are generally lacking and therefore limiting their application. Aims. We determined the effect of body size and temperature differential on the detection of snakes and frogs by passive infrared (PIR) wildlife cameras. We hypothesised that detection would differ among models and be positively correlated with body size and surface-temperature differential between the animal and substrate. We then conducted a field study to compare the detection of herpetofauna by a traditional method with PIR cameras. Methods. We tested 10 cameras of seven models on five snakes and one camera on six frogs. Photographs were downloaded to determine the detection rate of each species by each camera. We then chose a camera model to compare two herpetofauna survey methods, namely, drift fences equipped with cameras and visualencounter surveys. Surveys were conducted monthly over 12 months in Irwin County, GA, USA. Key results. The highest mean detection rates of snakes were 0.65 (s.e. = 0.33), 0.50 (s.e. = 0.34), and 0.49 (s.e. = 0.34) for the Browning Dark Ops, Reconyx Hyperfire 2, and Mossy Oak Covert Scouting Camera respectively. The detectability of larger snakes was greater than that of smaller snakes and increased as the absolute temperature differences between the snake and the substrate increased. The detectability of frogs was influenced by absolute temperature differential alone. PIR cameras generated five times more observations, documented more herpetofauna species, and were seven times more efficient than traditional surveys. Conclusions. The effectiveness of PIR cameras to detect herpetofauna varies among models and depends on the likelihood that the animal will have a body temperature significantly different from the temperature of the substrate. PIR cameras generated observations far more efficiently than traditional sampling methods. Implications. PIR wildlife cameras may be most effective at detecting larger, diurnal herpetofauna and least effective at detecting smaller, nocturnal species. Wildlife cameras have the potential to efficiently monitor some herpetofauna, providing a means to better evaluate management objectives.

@article{bradke_evaluating_2023,
	title = {Evaluating uncertainty to improve a common monitoring method and guide management decisions for diamond‐backed terrapins},
	volume = {88},
	url = {https://wildlife.onlinelibrary.wiley.com/doi/pdf/10.1002/jwmg.22513},
	abstract = {Designing monitoring with adequate certainty to evaluate management actions can be challenging, especially for elusive species in relatively inaccessible habitats. The diamond‐backed terrapin (Malaclemys terrapin) is considered a high priority species for management in all states within its range. Among key threats to terrapin populations is bycatch mortality in crab pots, prompting states throughout the species' range to consider crabbing regulations and creating a need for a monitoring approach able to evaluate the success of any new crabbing regulations to benefit terrapins. Because terrapins occupy extensive and often difficult to access estuarine habitat, it is hard to collect sufficient data to estimate population responses accurately and precisely for manage- ment. To assist state managers with decisions regarding monitoring bycatch reduction regulations, we modeled 12 years of terrapin capture‐recapture data. We used estimates from those models to simulate capture‐recapture data pre‐ and post‐implementation of bycatch reduction that resulted in a 0.20 absolute increase in mean apparent survival probability. Results indicated weak reliability of a monitoring approach using only manual seining of tidal creeks to detect a real management effect, with a positive management effect detected at the 95\% certainty level only 34\% of the time. When we considered 85\% and 75\% certainty thresholds, we detected a positive effect on survival among 61\% and 75\% of simulations, respectively. Low within‐year recapture probabil- ity and the effect of tide amplitude on terrapin availability indicate there is low feasibility of improving monitoring precision at a single site, requiring monitoring of more sites to improve confidence in the detection of the management effect. The number of sites monitored depends on the acceptable level of certainty. We recommend that researchers and management entities that use seining assess the level of certainty they require to evaluate management actions and increase the number of sites sampled to meet that level of certainty. Additionally, the use of multiple monitoring methods and integrated models should be explored to reduce uncer- tainty and to allow for easier monitoring of more populations over broader spatial scales.},
	language = {en},
	journal = {Journal of Wildlife Management},
	author = {Bradke, Danielle R and Maerz, John C and Crawford, Brian A and Kaylor, Michelle},
	year = {2023},
	pages = {e22513},
}

Designing monitoring with adequate certainty to evaluate management actions can be challenging, especially for elusive species in relatively inaccessible habitats. The diamond‐backed terrapin (Malaclemys terrapin) is considered a high priority species for management in all states within its range. Among key threats to terrapin populations is bycatch mortality in crab pots, prompting states throughout the species' range to consider crabbing regulations and creating a need for a monitoring approach able to evaluate the success of any new crabbing regulations to benefit terrapins. Because terrapins occupy extensive and often difficult to access estuarine habitat, it is hard to collect sufficient data to estimate population responses accurately and precisely for manage- ment. To assist state managers with decisions regarding monitoring bycatch reduction regulations, we modeled 12 years of terrapin capture‐recapture data. We used estimates from those models to simulate capture‐recapture data pre‐ and post‐implementation of bycatch reduction that resulted in a 0.20 absolute increase in mean apparent survival probability. Results indicated weak reliability of a monitoring approach using only manual seining of tidal creeks to detect a real management effect, with a positive management effect detected at the 95% certainty level only 34% of the time. When we considered 85% and 75% certainty thresholds, we detected a positive effect on survival among 61% and 75% of simulations, respectively. Low within‐year recapture probabil- ity and the effect of tide amplitude on terrapin availability indicate there is low feasibility of improving monitoring precision at a single site, requiring monitoring of more sites to improve confidence in the detection of the management effect. The number of sites monitored depends on the acceptable level of certainty. We recommend that researchers and management entities that use seining assess the level of certainty they require to evaluate management actions and increase the number of sites sampled to meet that level of certainty. Additionally, the use of multiple monitoring methods and integrated models should be explored to reduce uncer- tainty and to allow for easier monitoring of more populations over broader spatial scales.

@article{cayuela_sexrelated_2022,
	title = {Sex‐related differences in aging rate are associated with sex chromosome system in amphibians},
	copyright = {All rights reserved},
	issn = {0014-3820, 1558-5646},
	url = {https://www.dropbox.com/scl/fi/7pqh2ky4efac89kymk5t2/Cayuela-et-al-2022-Evolution-sex-related-differences-in-aging-and-sex-chromosomes.pdf?rlkey=aq05oo9qtjmypwws97b6u7yt3&dl=0},
	doi = {10.1111/evo.14410},
	abstract = {Sex-related differences in mortality are widespread in the animal kingdom. Although studies have shown that sex determination systems might drive lifespan evolution, sex chromosome influence on aging rates have not been investigated so far, likely due to an apparent lack of demographic data from clades including both XY (with heterogametic males) and ZW (heterogametic females) systems. Taking advantage of a unique collection of capture–recapture datasets in amphibians, a vertebrate group where XY and ZW systems have repeatedly evolved over the past 200 million years, we examined whether sex heterogamy can predict sex differences in aging rates and lifespans. We showed that the strength and direction of sex differences in aging rates (and not lifespan) differ between XY and ZW systems. Sex-specific variation in aging rates was moderate within each system, but aging rates tended to be consistently higher in the heterogametic sex. This led to small but detectable effects of sex chromosome system on sex differences in aging rates in our models. Although preliminary, our results suggest that exposed recessive deleterious mutations on the X/Z chromosome (the “unguarded X/Z effect”) or repeat-rich Y/W chromosome (the “toxic Y/W effect”) could accelerate aging in the heterogametic sex in some vertebrate clades.},
	language = {en},
	urldate = {2022-01-10},
	journal = {Evolution},
	author = {Cayuela, Hugo and Lemaître, Jean‐François and Léna, Jean‐Paul and Ronget, Victor and Martínez‐Solano, Iñigo and Muths, Erin and Pilliod, David S. and Schmidt, Benedikt R. and Sánchez‐Montes, Gregorio and Gutiérrez‐Rodríguez, Jorge and Pyke, Graham and Grossenbacher, Kurt and Lenzi, Omar and Bosch, Jaime and Beard, Karen H. and Woolbright, Lawrence L. and Lambert, Brad A. and Green, David M. and Jreidini, Nathalie and Garwood, Justin M. and Fisher, Robert N. and Matthews, Kathleen and Dudgeon, David and Lau, Anthony and Speybroeck, Jeroen and Homan, Rebecca and Jehle, Robert and Başkale, Eyup and Mori, Emiliano and Arntzen, Jan W. and Joly, Pierre and Stiles, Rochelle M. and Lannoo, Michael J. and Maerz, John C. and Lowe, Winsor H. and Valenzuela‐Sánchez, Andrés and Christiansen, Ditte G. and Angelini, Claudio and Thirion, Jean‐Marc and Merilä, Juha and Colli, Guarino R. and Vasconcellos, Mariana M. and Boas, Taissa C. V. and Arantes, Ísis da C. and Levionnois, Pauline and Reinke, Beth A. and Vieira, Cristina and Marais, Gabriel A. B. and Gaillard, Jean‐Michel and Miller, David A. W.},
	month = jan,
	year = {2022},
	pages = {evo.14410},
}

Sex-related differences in mortality are widespread in the animal kingdom. Although studies have shown that sex determination systems might drive lifespan evolution, sex chromosome influence on aging rates have not been investigated so far, likely due to an apparent lack of demographic data from clades including both XY (with heterogametic males) and ZW (heterogametic females) systems. Taking advantage of a unique collection of capture–recapture datasets in amphibians, a vertebrate group where XY and ZW systems have repeatedly evolved over the past 200 million years, we examined whether sex heterogamy can predict sex differences in aging rates and lifespans. We showed that the strength and direction of sex differences in aging rates (and not lifespan) differ between XY and ZW systems. Sex-specific variation in aging rates was moderate within each system, but aging rates tended to be consistently higher in the heterogametic sex. This led to small but detectable effects of sex chromosome system on sex differences in aging rates in our models. Although preliminary, our results suggest that exposed recessive deleterious mutations on the X/Z chromosome (the “unguarded X/Z effect”) or repeat-rich Y/W chromosome (the “toxic Y/W effect”) could accelerate aging in the heterogametic sex in some vertebrate clades.

@article{burrow_how_2022,
	title = {How plants affect amphibian populations},
	volume = {97},
	issn = {1464-7931, 1469-185X},
	url = {https://onlinelibrary.wiley.com/doi/10.1111/brv.12861},
	doi = {10.1111/brv.12861},
	abstract = {Descriptions of amphibian habitat, both aquatic and terrestrial, often include plants as characteristics but seldom is it understood whether and how those plants affect amphibian ecology. Understanding how plants affect amphibian populations is needed to develop strategies to combat declines of some amphibian populations. Using a systematic approach, we reviewed and synthesized available literature on the effects of plants on pond-breeding amphibians during the aquatic and terrestrial stages of their life cycle. Our review highlights that plant communities can strongly influence the distribution, abundance, and performance of amphibians in multiple direct and indirect ways. We found three broad themes of plants’ influence on amphibians: plants can affect amphibians through effects on abiotic conditions including the thermal, hydric, and chemical aspects of an amphibian’s environment; plants can have large effects on aquatic life stages through effects on resource quality and abundance; and plants can modify the nature and strength of interspecific interactions between amphibians and other species – notably predators. We synthesized insights gained from the literature to discuss how plant community management fits within efforts to manage amphibian populations and to guide future research efforts. While some topical areas are well researched, we found a general lack of mechanistic and trait-based work which is needed to advance our understanding of the drivers through which plants influence amphibian ecology. Our literature review reveals the substantial role that plants can have on amphibian ecology and the need for integrating plant and amphibian ecology to improve research and management outcomes for amphibians.},
	language = {en},
	number = {5},
	urldate = {2023-01-06},
	journal = {Biological Reviews},
	author = {Burrow, Angela and Maerz, John},
	month = oct,
	year = {2022},
	pages = {1749--1767},
}

Descriptions of amphibian habitat, both aquatic and terrestrial, often include plants as characteristics but seldom is it understood whether and how those plants affect amphibian ecology. Understanding how plants affect amphibian populations is needed to develop strategies to combat declines of some amphibian populations. Using a systematic approach, we reviewed and synthesized available literature on the effects of plants on pond-breeding amphibians during the aquatic and terrestrial stages of their life cycle. Our review highlights that plant communities can strongly influence the distribution, abundance, and performance of amphibians in multiple direct and indirect ways. We found three broad themes of plants’ influence on amphibians: plants can affect amphibians through effects on abiotic conditions including the thermal, hydric, and chemical aspects of an amphibian’s environment; plants can have large effects on aquatic life stages through effects on resource quality and abundance; and plants can modify the nature and strength of interspecific interactions between amphibians and other species – notably predators. We synthesized insights gained from the literature to discuss how plant community management fits within efforts to manage amphibian populations and to guide future research efforts. While some topical areas are well researched, we found a general lack of mechanistic and trait-based work which is needed to advance our understanding of the drivers through which plants influence amphibian ecology. Our literature review reveals the substantial role that plants can have on amphibian ecology and the need for integrating plant and amphibian ecology to improve research and management outcomes for amphibians.

@article{crawford_breeding_2022,
	title = {Breeding {Dynamics} of {Gopher} {Frog} {Metapopulations} {Over} 10 {Years}},
	volume = {13},
	issn = {1944-687X},
	url = {https://meridian.allenpress.com/jfwm/article/13/2/422/482613/Breeding-Dynamics-of-Gopher-Frog-Metapopulations},
	doi = {10.3996/JFWM-21-076},
	abstract = {Populations of amphibians that breed in isolated, ephemeral wetlands may be particularly sensitive to breeding and recruitment rates, which can be influenced by dynamic and difficult-to-predict extrinsic factors. The gopher frog Rana capito is a declining species currently proposed for listing under the U.S. Endangered Species Act, as well as one of many pond-breeding amphibians of conservation concern in the southeastern United States. To represent gopher frog breeding dynamics, we applied an occupancy modeling framework that integrated multiple data sets collected across the species’ range to 1) estimate the influence of climate, habitat, and other factors on wetland-specific seasonal breeding probabilities; and 2) use those estimates to characterize seasonal, annual, and regional breeding patterns over a 10-y period. Breeding probability at a wetland was positively influenced by seasonal precipitation (Standardized Precipitation Index) and negatively influenced by fish presence. We found some evidence that the amount of suitable habitat surrounding a wetland was positively correlated with breeding probability during drought conditions. The percentage of sampled wetlands (N ¼ 192) predicted to have breeding varied seasonally, annually, and regionally across the study. Within-year temporal patterns of breeding differed across the range: in most locations north of Florida, peaks of breeding occurred in winter and spring months; whereas breeding was more dispersed throughout the year in Florida. Peaks of breeding across the 10-y period often occurred during or in the season following high rainfall events (e.g., hurricanes). These results have direct applications for site-level management that aims to increase successful breeding opportunities of gopher frogs and other associated pond-breeding amphibians, including monitoring protocol and intensity, removal of fish, and improving terrestrial habitat conditions surrounding wetlands (e.g., via tree or shrub removal and prescribed fire). The results also have implications for better-informed management through the closer alignment of breeding activity monitoring with predicted seasonal peaks. Furthermore, estimates of breeding frequency can be incorporated into population viability analyses to inform forthcoming assessments of extinction risk and designation of the species’ conservation status by the U.S. Fish and Wildlife Service.},
	language = {en},
	number = {2},
	urldate = {2023-01-06},
	journal = {Journal of Fish and Wildlife Management},
	author = {Crawford, Brian A. and Farmer, Anna L. and Enge, Kevin M. and Greene, Aubrey Heupel and Diaz, Lauren and Maerz, John C. and Moore, Clinton T.},
	month = dec,
	year = {2022},
	pages = {422--436},
}

Populations of amphibians that breed in isolated, ephemeral wetlands may be particularly sensitive to breeding and recruitment rates, which can be influenced by dynamic and difficult-to-predict extrinsic factors. The gopher frog Rana capito is a declining species currently proposed for listing under the U.S. Endangered Species Act, as well as one of many pond-breeding amphibians of conservation concern in the southeastern United States. To represent gopher frog breeding dynamics, we applied an occupancy modeling framework that integrated multiple data sets collected across the species’ range to 1) estimate the influence of climate, habitat, and other factors on wetland-specific seasonal breeding probabilities; and 2) use those estimates to characterize seasonal, annual, and regional breeding patterns over a 10-y period. Breeding probability at a wetland was positively influenced by seasonal precipitation (Standardized Precipitation Index) and negatively influenced by fish presence. We found some evidence that the amount of suitable habitat surrounding a wetland was positively correlated with breeding probability during drought conditions. The percentage of sampled wetlands (N ¼ 192) predicted to have breeding varied seasonally, annually, and regionally across the study. Within-year temporal patterns of breeding differed across the range: in most locations north of Florida, peaks of breeding occurred in winter and spring months; whereas breeding was more dispersed throughout the year in Florida. Peaks of breeding across the 10-y period often occurred during or in the season following high rainfall events (e.g., hurricanes). These results have direct applications for site-level management that aims to increase successful breeding opportunities of gopher frogs and other associated pond-breeding amphibians, including monitoring protocol and intensity, removal of fish, and improving terrestrial habitat conditions surrounding wetlands (e.g., via tree or shrub removal and prescribed fire). The results also have implications for better-informed management through the closer alignment of breeding activity monitoring with predicted seasonal peaks. Furthermore, estimates of breeding frequency can be incorporated into population viability analyses to inform forthcoming assessments of extinction risk and designation of the species’ conservation status by the U.S. Fish and Wildlife Service.

@article{crawford_population_2022,
	title = {Population viability analysis for a pond-breeding amphibian under future drought scenarios in the southeastern {United} {States}},
	volume = {36},
	copyright = {All rights reserved},
	issn = {23519894},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S2351989422001214},
	doi = {10.1016/j.gecco.2022.e02119},
	abstract = {Climate change effects are contributing to widespread declines of amphibians, and pond-breeding species may be particularly sensitive to future drought conditions that restrict wetland hydro­ periods and decrease opportunities for successful breeding and recruitment. Pond-breeding amphibian populations can compensate for periodic droughts via episodic booms in recruit­ ment, but studies predict that increased future drought conditions will negatively impact longterm persistence for several species. The southeastern United States is a global hotspot of amphibian biodiversity where future trends in drought conditions are uncertain. This study applied a population viability analysis (PVA) framework for an at-risk amphibian, the gopher frog (Lithobates [Rana] capito), to (i) explore population sensitivity to the frequency of droughts that restrict reproductive events, relative to changes in other demographic rates, and (ii) forecast future population viability over 30 years, given plausible scenarios varying in the frequency and duration of droughts adapted from recent historical patterns in the southeastern United States. Population persistence was highly sensitive to frequency of reproductive success. Persistence was fairly insensitive to all demographic parameters when reproductive success was ≥ 0.7 (i.e., ≤ 3 drought years per decade, on average), but sensitivity to survival of terrestrial stages (juvenile, adults) and initial abundance increased as reproductive success decreased. Persistence proba­ bilities were relatively high (0.63–0.99) across a range of plausible future drought scenarios, with higher persistence probabilities ({\textgreater} 0.89) for all scenarios where drought years did not increase from recent historical conditions. Our results indicate gopher frog populations are likely resilient to periodic droughts that occur in 4 or fewer years per decade, but extirpation of some pop­ ulations is possible if recent drought patterns repeat or increase during the next 30 years. Esti­ mates of future risk to gopher frog populations can inform forthcoming status assessments and designation decisions of the U.S. Fish and Wildlife Service. More broadly, PVAs incorporating drought dynamics can identify climate thresholds that at-risk, pond-breeding amphibian pop­ ulations can tolerate, which can inform management actions (e.g., maintaining a range of hydroperiods across proximate wetlands) that provide sufficient frequent breeding opportunities for long-term persistence even under drought conditions.},
	language = {en},
	urldate = {2022-05-04},
	journal = {Global Ecology and Conservation},
	author = {Crawford, Brian A. and Maerz, John C. and Terrell, Vanessa C.K. and Moore, Clinton T.},
	month = aug,
	year = {2022},
	pages = {e02119},
}

Climate change effects are contributing to widespread declines of amphibians, and pond-breeding species may be particularly sensitive to future drought conditions that restrict wetland hydro­ periods and decrease opportunities for successful breeding and recruitment. Pond-breeding amphibian populations can compensate for periodic droughts via episodic booms in recruit­ ment, but studies predict that increased future drought conditions will negatively impact longterm persistence for several species. The southeastern United States is a global hotspot of amphibian biodiversity where future trends in drought conditions are uncertain. This study applied a population viability analysis (PVA) framework for an at-risk amphibian, the gopher frog (Lithobates [Rana] capito), to (i) explore population sensitivity to the frequency of droughts that restrict reproductive events, relative to changes in other demographic rates, and (ii) forecast future population viability over 30 years, given plausible scenarios varying in the frequency and duration of droughts adapted from recent historical patterns in the southeastern United States. Population persistence was highly sensitive to frequency of reproductive success. Persistence was fairly insensitive to all demographic parameters when reproductive success was ≥ 0.7 (i.e., ≤ 3 drought years per decade, on average), but sensitivity to survival of terrestrial stages (juvenile, adults) and initial abundance increased as reproductive success decreased. Persistence proba­ bilities were relatively high (0.63–0.99) across a range of plausible future drought scenarios, with higher persistence probabilities (\textgreater 0.89) for all scenarios where drought years did not increase from recent historical conditions. Our results indicate gopher frog populations are likely resilient to periodic droughts that occur in 4 or fewer years per decade, but extirpation of some pop­ ulations is possible if recent drought patterns repeat or increase during the next 30 years. Esti­ mates of future risk to gopher frog populations can inform forthcoming status assessments and designation decisions of the U.S. Fish and Wildlife Service. More broadly, PVAs incorporating drought dynamics can identify climate thresholds that at-risk, pond-breeding amphibian pop­ ulations can tolerate, which can inform management actions (e.g., maintaining a range of hydroperiods across proximate wetlands) that provide sufficient frequent breeding opportunities for long-term persistence even under drought conditions.

@article{howard_model_2022,
	title = {A {Model} for {Estimating} {Final} {Clutch} {Size} from {Follicle} {Counts} in {Plethodontid} {Salamanders}},
	volume = {56},
	issn = {0022-1511},
	url = {https://bioone.org/journals/journal-of-herpetology/volume-56/issue-2/21-015/A-Model-for-Estimating-Final-Clutch-Size-from-Follicle-Counts/10.1670/21-015.full},
	doi = {10.1670/21-015},
	abstract = {Estimates of clutch sizes are essential for modeling population dynamics, yet for many species of amphibian, clutches can be difficult to observe or methodologically problematic to measure. Clutch sizes for direct-developing Plethodontidae are regularly estimated from counts of ovarian follicles. Because many more follicles begin to develop in an ovary than will ultimately reach full size and be deposited, follicle counts change dramatically over an individual female’s follicle development cycle, and a high level of subjectivity is inherent in the process of estimating clutch sizes from follicle counts. Many published studies are not transparent in how they determine clutch sizes from follicle counts. Some investigators address this bias using threshold sizes or other characteristics to separate those follicles that will ultimately mature and be deposited from those that will not, but our experience indicates that such approaches still likely overestimate clutch sizes. To move beyond the subjectivity inherent in estimation of final clutch size from follicle counts, we modeled large Plethodon clutch size as a function of female body size (snout–vent length, SVL) and follicle diameter, then used that model to predict the likely number of mature eggs deposited. We propose that this approach provides reasonable estimates of clutch sizes and variances for use in demographic models.},
	language = {en},
	number = {2},
	urldate = {2022-09-06},
	journal = {Journal of Herpetology},
	author = {Howard, Jillian S. and Maerz, John C.},
	month = aug,
	year = {2022},
}

Estimates of clutch sizes are essential for modeling population dynamics, yet for many species of amphibian, clutches can be difficult to observe or methodologically problematic to measure. Clutch sizes for direct-developing Plethodontidae are regularly estimated from counts of ovarian follicles. Because many more follicles begin to develop in an ovary than will ultimately reach full size and be deposited, follicle counts change dramatically over an individual female’s follicle development cycle, and a high level of subjectivity is inherent in the process of estimating clutch sizes from follicle counts. Many published studies are not transparent in how they determine clutch sizes from follicle counts. Some investigators address this bias using threshold sizes or other characteristics to separate those follicles that will ultimately mature and be deposited from those that will not, but our experience indicates that such approaches still likely overestimate clutch sizes. To move beyond the subjectivity inherent in estimation of final clutch size from follicle counts, we modeled large Plethodon clutch size as a function of female body size (snout–vent length, SVL) and follicle diameter, then used that model to predict the likely number of mature eggs deposited. We propose that this approach provides reasonable estimates of clutch sizes and variances for use in demographic models.

@article{marshall_gopher_2022,
	title = {Gopher tortoise ({Gopherus} polyphemus) resource selection within a private working pine ({Pinus} spp.) forest landscape},
	volume = {510},
	issn = {03781127},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0378112722001062},
	doi = {10.1016/j.foreco.2022.120112},
	abstract = {Private working forest landscapes provide wildlife habitat and understanding how species interact with these landscapes is critical to identifying conservation opportunities. The gopher tortoise (Gopherus polyphemus; hereafter, tortoise) is a species endemic to the Coastal Plain ecoregion of the southeastern United States, with private working pine (Pinus spp.) forests encompassing a substantive portion of area within the species’ range. Although private working pine forests contain tortoises, uncertainty exists about how tortoises use these land­ scapes. Specifically, there is limited information regarding tortoise habitat associations within these landscapes relative to current forest management practices. Therefore, we used radio telemetry data from 55 adult tortoises collected over 3 years to estimate resource selection within a private working forest landscape dominated by planted loblolly pine (Pinus taeda) stands in the Upper Coastal Plain ecoregion of Georgia, USA. The strongest predictor of resource selection by tortoises was proximity to permanently open areas, specifically a utility rightof-way and areas adjacent to unpaved forest roads and, to a lesser extent, areas of higher elevation containing soils suitable for tortoises. On our study area, we identified permanently open areas as an important landscape component to adult tortoises. Although adult tortoises persist within these landscapes, more work is needed to understand tortoise recruitment in private working pine forest landscapes.},
	language = {en},
	urldate = {2025-01-21},
	journal = {Forest Ecology and Management},
	author = {Marshall, Craig D. and Maerz, John C. and Larsen-Gray, Angela L. and Chamberlain, Michael J. and Martin, James A.},
	month = apr,
	year = {2022},
	pages = {120112},
}

Private working forest landscapes provide wildlife habitat and understanding how species interact with these landscapes is critical to identifying conservation opportunities. The gopher tortoise (Gopherus polyphemus; hereafter, tortoise) is a species endemic to the Coastal Plain ecoregion of the southeastern United States, with private working pine (Pinus spp.) forests encompassing a substantive portion of area within the species’ range. Although private working pine forests contain tortoises, uncertainty exists about how tortoises use these land­ scapes. Specifically, there is limited information regarding tortoise habitat associations within these landscapes relative to current forest management practices. Therefore, we used radio telemetry data from 55 adult tortoises collected over 3 years to estimate resource selection within a private working forest landscape dominated by planted loblolly pine (Pinus taeda) stands in the Upper Coastal Plain ecoregion of Georgia, USA. The strongest predictor of resource selection by tortoises was proximity to permanently open areas, specifically a utility rightof-way and areas adjacent to unpaved forest roads and, to a lesser extent, areas of higher elevation containing soils suitable for tortoises. On our study area, we identified permanently open areas as an important landscape component to adult tortoises. Although adult tortoises persist within these landscapes, more work is needed to understand tortoise recruitment in private working pine forest landscapes.

@article{reinke_diverse_2022,
	title = {Diverse aging rates in ectothermic tetrapods provide insights for the evolution of aging and longevity},
	volume = {376},
	copyright = {All rights reserved},
	issn = {0036-8075, 1095-9203},
	url = {https://www.science.org/doi/10.1126/science.abm0151},
	doi = {10.1126/science.abm0151},
	abstract = {Comparative studies of mortality in the wild are necessary to understand the evolution of aging; yet, ectothermic tetrapods are underrepresented in this comparative landscape, despite their suitability for testing evolutionary hypotheses. We present a study of aging rates and longevity across wild tetrapod ectotherms, using data from 107 populations (77 species) of nonavian reptiles and amphibians. We test hypotheses of how thermoregulatory mode, environmental temperature, protective phenotypes, and pace of life history contribute to demographic aging. Controlling for phylogeny and body size, ectotherms display a higher diversity of aging rates compared with endotherms and include phylogenetically widespread evidence of negligible aging. Protective phenotypes and life-history strategies further explain macroevolutionary patterns of aging. Analyzing ectothermic tetrapods in a comparative context enhances our understanding of the evolution of aging.
          , 
            How to cheat senescence?
            
              Compared with birds and mammals, herpetiles, especially turtles and tortoises, are well-known examples of extremely long-lived animals that show little evidence of age-related decline (see the Perspective by Austad and Finch). By comparing aging rates and longevity across 77 species of reptiles and amphibians, Reinke
              et al
              . found considerable variation in senescence and elucidated some of the drivers of these differences in nature. In another paper, Da Silva
              et al
              . studied turtles and tortoises in zoos and found clear evidence that negligible senescence occurs under controlled conditions. —SNV
            
          , 
            In the wild, the aging rates of reptiles and amphibians range from negligible to fast depending on protective traits and pace of lifestyle.},
	language = {en},
	number = {6600},
	urldate = {2022-06-25},
	journal = {Science},
	author = {Reinke, Beth A. and Cayuela, Hugo and Janzen, Fredric J. and Lemaître, Jean-François and Gaillard, Jean-Michel and Lawing, A. Michelle and Iverson, John B. and Christiansen, Ditte G. and Martínez-Solano, Iñigo and Sánchez-Montes, Gregorio and Gutiérrez-Rodríguez, Jorge and Rose, Francis L. and Nelson, Nicola and Keall, Susan and Crivelli, Alain J. and Nazirides, Theodoros and Grimm-Seyfarth, Annegret and Henle, Klaus and Mori, Emiliano and Guiller, Gaëtan and Homan, Rebecca and Olivier, Anthony and Muths, Erin and Hossack, Blake R. and Bonnet, Xavier and Pilliod, David S. and Lettink, Marieke and Whitaker, Tony and Schmidt, Benedikt R. and Gardner, Michael G. and Cheylan, Marc and Poitevin, Françoise and Golubović, Ana and Tomović, Ljiljana and Arsovski, Dragan and Griffiths, Richard A. and Arntzen, Jan W. and Baron, Jean-Pierre and Le Galliard, Jean-François and Tully, Thomas and Luiselli, Luca and Capula, Massimo and Rugiero, Lorenzo and McCaffery, Rebecca and Eby, Lisa A. and Briggs-Gonzalez, Venetia and Mazzotti, Frank and Pearson, David and Lambert, Brad A. and Green, David M. and Jreidini, Nathalie and Angelini, Claudio and Pyke, Graham and Thirion, Jean-Marc and Joly, Pierre and Léna, Jean-Paul and Tucker, Anton D. and Limpus, Col and Priol, Pauline and Besnard, Aurélien and Bernard, Pauline and Stanford, Kristin and King, Richard and Garwood, Justin and Bosch, Jaime and Souza, Franco L. and Bertoluci, Jaime and Famelli, Shirley and Grossenbacher, Kurt and Lenzi, Omar and Matthews, Kathleen and Boitaud, Sylvain and Olson, Deanna H. and Jessop, Tim S. and Gillespie, Graeme R. and Clobert, Jean and Richard, Murielle and Valenzuela-Sánchez, Andrés and Fellers, Gary M. and Kleeman, Patrick M. and Halstead, Brian J. and Grant, Evan H. Campbell and Byrne, Phillip G. and Frétey, Thierry and Le Garff, Bernard and Levionnois, Pauline and Maerz, John C. and Pichenot, Julian and Olgun, Kurtuluş and Üzüm, Nazan and Avcı, Aziz and Miaud, Claude and Elmberg, Johan and Brown, Gregory P. and Shine, Richard and Bendik, Nathan F. and O’Donnell, Lisa and Davis, Courtney L. and Lannoo, Michael J. and Stiles, Rochelle M. and Cox, Robert M. and Reedy, Aaron M. and Warner, Daniel A. and Bonnaire, Eric and Grayson, Kristine and Ramos-Targarona, Roberto and Baskale, Eyup and Muñoz, David and Measey, John and de Villiers, F. Andre and Selman, Will and Ronget, Victor and Bronikowski, Anne M. and Miller, David A. W.},
	month = jun,
	year = {2022},
	pages = {1459--1466},
}

Comparative studies of mortality in the wild are necessary to understand the evolution of aging; yet, ectothermic tetrapods are underrepresented in this comparative landscape, despite their suitability for testing evolutionary hypotheses. We present a study of aging rates and longevity across wild tetrapod ectotherms, using data from 107 populations (77 species) of nonavian reptiles and amphibians. We test hypotheses of how thermoregulatory mode, environmental temperature, protective phenotypes, and pace of life history contribute to demographic aging. Controlling for phylogeny and body size, ectotherms display a higher diversity of aging rates compared with endotherms and include phylogenetically widespread evidence of negligible aging. Protective phenotypes and life-history strategies further explain macroevolutionary patterns of aging. Analyzing ectothermic tetrapods in a comparative context enhances our understanding of the evolution of aging. , How to cheat senescence? Compared with birds and mammals, herpetiles, especially turtles and tortoises, are well-known examples of extremely long-lived animals that show little evidence of age-related decline (see the Perspective by Austad and Finch). By comparing aging rates and longevity across 77 species of reptiles and amphibians, Reinke et al . found considerable variation in senescence and elucidated some of the drivers of these differences in nature. In another paper, Da Silva et al . studied turtles and tortoises in zoos and found clear evidence that negligible senescence occurs under controlled conditions. —SNV , In the wild, the aging rates of reptiles and amphibians range from negligible to fast depending on protective traits and pace of lifestyle.

@article{ashley_effects_2021,
	title = {Effects of {Salinity} on {Hatchling} {Diamond}-{Backed} {Terrapin} ({Malaclemys} terrapin) {Growth}, {Behavior}, and {Stress} {Physiology}},
	volume = {77},
	copyright = {All rights reserved},
	url = {https://www.dropbox.com/scl/fi/cw2qdooaqzhr8tazrchg7/Ashley-et-al-2021-Herpetologica-D-20-00028.1.pdf?rlkey=pca0w4pa44g8qlcbls8iu8ou2&dl=0},
	abstract = {Diamond-backed Terrapins inhabit coastal salt marshes along the eastern and Gulf coasts of North America. Terrapins are adapted to intermediate salinities yet frequently face saltwater-inundated marsh habitat exceeding 25 ppt (or grams/kilogram). We investigated the effect of salinity on the growth of hatchling terrapins and on their compensatory responses to salinity stress. We randomly assigned 30 terrapin hatchlings each to one of five salinity treatments (1, 5, 10, 20, or 35 ppt). Over 75 d, we regularly monitored behavior, appetite, and changes in growth; and calculated ratios of heterophils to lymphocytes (H:L ratio) to assess responses to prolonged salinity stress. Consistent with prior studies, chronic exposure to high salinity significantly reduced hatchling growth. Hatchlings in 20-ppt and 35-ppt salinities exhibited appetite suppression and saltwater avoidance and were more likely to show freshwater-seeking behaviors. H:L ratios were higher among hatchlings in 20and 35-ppt salinities, consistent with a corticosterone-driven stress response to sustained high-salinity exposure, which may play a role in limiting growth. Our findings suggest hatchling growth and distribution among local habitats will vary spatially depending on habitat salinity and freshwater accessibility. The growth-limiting effects of chronically high salinity or limited access to freshwater could therefore increase hatchling mortality and be an important driver of spatial variation in terrapin demography and abundance. However, when freshwater sources are available, compensatory behaviors might reduce growth-limiting effects. Terrapin recruitment is likely to be impacted as rising sea levels, increased human water use, land development, and other anthropogenic changes alter freshwater inputs to coastal marshes.},
	language = {en},
	number = {1},
	journal = {Herpetologica},
	author = {Ashley, Elizabeth A and Davis, Andrew K and Terrell, Vanessa K and Lake, Connor and Carden, Cady and Head, Lauren and Maerz, John C},
	year = {2021},
	pages = {45--55},
}

Diamond-backed Terrapins inhabit coastal salt marshes along the eastern and Gulf coasts of North America. Terrapins are adapted to intermediate salinities yet frequently face saltwater-inundated marsh habitat exceeding 25 ppt (or grams/kilogram). We investigated the effect of salinity on the growth of hatchling terrapins and on their compensatory responses to salinity stress. We randomly assigned 30 terrapin hatchlings each to one of five salinity treatments (1, 5, 10, 20, or 35 ppt). Over 75 d, we regularly monitored behavior, appetite, and changes in growth; and calculated ratios of heterophils to lymphocytes (H:L ratio) to assess responses to prolonged salinity stress. Consistent with prior studies, chronic exposure to high salinity significantly reduced hatchling growth. Hatchlings in 20-ppt and 35-ppt salinities exhibited appetite suppression and saltwater avoidance and were more likely to show freshwater-seeking behaviors. H:L ratios were higher among hatchlings in 20and 35-ppt salinities, consistent with a corticosterone-driven stress response to sustained high-salinity exposure, which may play a role in limiting growth. Our findings suggest hatchling growth and distribution among local habitats will vary spatially depending on habitat salinity and freshwater accessibility. The growth-limiting effects of chronically high salinity or limited access to freshwater could therefore increase hatchling mortality and be an important driver of spatial variation in terrapin demography and abundance. However, when freshwater sources are available, compensatory behaviors might reduce growth-limiting effects. Terrapin recruitment is likely to be impacted as rising sea levels, increased human water use, land development, and other anthropogenic changes alter freshwater inputs to coastal marshes.

@article{howard_review_2021,
	title = {Review and {Synthesis} of {Estimated} {Vital} {Rates} for {Terrestrial} {Salamanders} in the {Family} {Plethodontidae}},
	volume = {109},
	copyright = {All rights reserved},
	issn = {2766-1512},
	url = {https://bioone.org/journals/ichthyology-and-herpetology/volume-109/issue-4/h2020079/Review-and-Synthesis-of-Estimated-Vital-Rates-for-Terrestrial-Salamanders/10.1643/h2020079.full},
	doi = {10.1643/h2020079},
	abstract = {Population models depend on reliable estimates of vital rates, yet for many taxa, such estimates and how they vary in response to spatial or temporal environmental gradients are lacking. The goal of this review was to determine whether existing estimates of vital rates for temperate, direct-developing plethodontid salamanders (subfamily Plethodontinae) could be used to reasonably project values for populations or species where such estimates are lacking, or whether current estimates are biased in a manner that limits their utility. We synthesized current knowledge of stage-specific survival rates, age- and size-at-maturity at first clutch, and clutch frequency. We tested for expected correlations among published vital rates (e.g., age at maturity and survival) and between vital rates and factors such as body size or latitude. We used matrix projection models to judge whether published estimates were reasonably possible for stable salamander populations. The largest number of published vital rates were for clutch size, clutch frequency (proportion of females with clutches), size at maturity or first clutch, and age at maturity or first clutch, though the latter vital rate is primarily inferred from size distribution and growth rate data. Among these vital rates, we found expected correlations with body size and latitude suggesting these rates were reasonable and somewhat predictable among species or populations. In contrast, there were few estimates of egg hatch rate or juvenile or adult survival. Hatch and survival rate estimates were widely variable; estimates seldom included measures of uncertainty, but when uncertainty measurements were included, they were generally high. Based on projection models, few survival estimates were likely unbiased or realistic for stable populations given other salamander vital rates. Additionally, few studies quantified how vital rates vary with spatial or temporal environmental gradients. We outline the key knowledge gaps that limit basic demographic modeling of these remarkably common, influential, and otherwise well-studied salamanders, and make recommendations for future research efforts.},
	language = {en},
	number = {4},
	urldate = {2022-01-23},
	journal = {Ichthyology \& Herpetology},
	author = {Howard, Jillian S. and Maerz, John C.},
	month = oct,
	year = {2021},
	pages = {929--939},
}

Population models depend on reliable estimates of vital rates, yet for many taxa, such estimates and how they vary in response to spatial or temporal environmental gradients are lacking. The goal of this review was to determine whether existing estimates of vital rates for temperate, direct-developing plethodontid salamanders (subfamily Plethodontinae) could be used to reasonably project values for populations or species where such estimates are lacking, or whether current estimates are biased in a manner that limits their utility. We synthesized current knowledge of stage-specific survival rates, age- and size-at-maturity at first clutch, and clutch frequency. We tested for expected correlations among published vital rates (e.g., age at maturity and survival) and between vital rates and factors such as body size or latitude. We used matrix projection models to judge whether published estimates were reasonably possible for stable salamander populations. The largest number of published vital rates were for clutch size, clutch frequency (proportion of females with clutches), size at maturity or first clutch, and age at maturity or first clutch, though the latter vital rate is primarily inferred from size distribution and growth rate data. Among these vital rates, we found expected correlations with body size and latitude suggesting these rates were reasonable and somewhat predictable among species or populations. In contrast, there were few estimates of egg hatch rate or juvenile or adult survival. Hatch and survival rate estimates were widely variable; estimates seldom included measures of uncertainty, but when uncertainty measurements were included, they were generally high. Based on projection models, few survival estimates were likely unbiased or realistic for stable populations given other salamander vital rates. Additionally, few studies quantified how vital rates vary with spatial or temporal environmental gradients. We outline the key knowledge gaps that limit basic demographic modeling of these remarkably common, influential, and otherwise well-studied salamanders, and make recommendations for future research efforts.

@article{burrow_ground_2021,
	title = {Ground cover and native ant predation influence survival of metamorphic amphibians in a southeastern pine savanna undergoing restoration},
	volume = {29},
	copyright = {All rights reserved},
	issn = {1061-2971, 1526-100X},
	url = {https://onlinelibrary.wiley.com/doi/10.1111/rec.13410},
	doi = {10.1111/rec.13410},
	abstract = {Longleaf pine savannas historically supported abundant ground cover maintained by frequent fire but little other disturbance. Ground cover creates microclimates with lower temperatures, higher humidity, and increased soil moisture that may benefit wildlife, particularly small vertebrates such as amphibians. Today, most historical pine savannas have had extensive soil disturbance and altered fire regimes resulting in reduced ground cover and altered soil fauna communities including predatory invertebrates. We used a factorial terrestrial cage study to test the effects of native wiregrass (Aristida spp.) cover and the exclusion of a native predatory ant (Dorymyrmex smithi) on the survival of post-metamorphic Ornate chorus frogs (Pseudacris ornata) and Gopher frogs (Rana capito). Although we were unable to achieve full ant exclusion, ant reduction in exclusion treatments and plant cover had an interactive effect on metamorph survival. Ant exclusion tended to increase Gopher frog survival and this effect was more pronounced when wiregrass was present. Within ant treatments, survival of Gopher frogs increased slightly with increasing wiregrass cover. Ornate chorus frogs had a high probability of survival ({\textgreater}95\%) in all ant exclusion treatments regardless of wiregrass cover; however, in treatments without ant exclusion, survival increased with increasing wiregrass cover. Our results demonstrate that high abundances of a native ant species and low coverage of native wiregrass, which are legacies of historical soil disturbance and altered fire regimes, interact to elevate mortality of juvenile amphibians. Minimizing soil disturbance and restoring native ground cover are likely important for amphibian habitat management within historical southeastern pine savannas.},
	language = {en},
	number = {7},
	urldate = {2021-07-07},
	journal = {Restoration Ecology},
	author = {Burrow, Angela K. and Crawford, Brian A. and Maerz, John C.},
	month = jun,
	year = {2021},
	pages = {e13410},
}

Longleaf pine savannas historically supported abundant ground cover maintained by frequent fire but little other disturbance. Ground cover creates microclimates with lower temperatures, higher humidity, and increased soil moisture that may benefit wildlife, particularly small vertebrates such as amphibians. Today, most historical pine savannas have had extensive soil disturbance and altered fire regimes resulting in reduced ground cover and altered soil fauna communities including predatory invertebrates. We used a factorial terrestrial cage study to test the effects of native wiregrass (Aristida spp.) cover and the exclusion of a native predatory ant (Dorymyrmex smithi) on the survival of post-metamorphic Ornate chorus frogs (Pseudacris ornata) and Gopher frogs (Rana capito). Although we were unable to achieve full ant exclusion, ant reduction in exclusion treatments and plant cover had an interactive effect on metamorph survival. Ant exclusion tended to increase Gopher frog survival and this effect was more pronounced when wiregrass was present. Within ant treatments, survival of Gopher frogs increased slightly with increasing wiregrass cover. Ornate chorus frogs had a high probability of survival (\textgreater95%) in all ant exclusion treatments regardless of wiregrass cover; however, in treatments without ant exclusion, survival increased with increasing wiregrass cover. Our results demonstrate that high abundances of a native ant species and low coverage of native wiregrass, which are legacies of historical soil disturbance and altered fire regimes, interact to elevate mortality of juvenile amphibians. Minimizing soil disturbance and restoring native ground cover are likely important for amphibian habitat management within historical southeastern pine savannas.

@article{burrow_experimental_2021,
	title = {Experimental confirmation of effects of leaf litter type and light on tadpole performance for two priority amphibians},
	volume = {12},
	copyright = {All rights reserved},
	issn = {2150-8925, 2150-8925},
	url = {https://onlinelibrary.wiley.com/doi/10.1002/ecs2.3729},
	doi = {10.1002/ecs2.3729},
	abstract = {Isolated wetlands embedded within longleaf pine savannas support a high proportion of regional biodiversity including many amphibian species. Today, remnant isolated wetlands are often overgrown and hydrologically altered due to fire exclusion or incompatible, cool season fire regimes. In the absence of warm season fires when wetlands are dry, shrubs and trees succeed herbaceous plants, which alters wetland productivity via effects on light and detritus quality. We used a factorial aquatic mesocosm study to test the effects of altered detritus and shade on the growth, development, and survival of tadpoles of two priority amphibian species: gopher frogs (Rana capito) and ornate chorus frogs (Pseudacris ornata). Gopher frog survival was higher among maidencane, sedge, and pine treatments compared to oak and sweetgum treatments. While gopher frog larval periods were lowest in the sedge treatment, there was a nominal general effect of litter type on gopher frog larval periods, growth rates, and mass at metamorphosis. Shading had a nominal and inconsistent effect on gopher frog growth rates, but did extend larval periods in all litter treatments, decreased survival in all litter treatments except oak, and decreased mass at metamorphosis in all litter treatments except pine and sweetgum. Ornate chorus frog survival was minimally affected by shading and litter treatments, but growth rates and mass at metamorphosis were highest in maidencane and sedge treatments, and larval periods were extended with shading in all litter treatments. Shading also decreased growth rates in maidencane and sedge litters and decreased mass at metamorphosis in pine and sweetgum litters. Our results demonstrate that succession of isolated wetlands can reduce tadpole performance for two priority species both through changes in leaf litter and shading, though the effect on survival, larval growth, larval period, and size at metamorphosis can differ between species. These results support management recommendations to restore and maintain open canopy, grassy conditions in isolated wetlands for conservation of priority amphibian species.},
	language = {en},
	number = {9},
	urldate = {2022-01-26},
	journal = {Ecosphere},
	author = {Burrow, Angela K. and Maerz, John C.},
	month = sep,
	year = {2021},
	pages = {e03729},
}

Isolated wetlands embedded within longleaf pine savannas support a high proportion of regional biodiversity including many amphibian species. Today, remnant isolated wetlands are often overgrown and hydrologically altered due to fire exclusion or incompatible, cool season fire regimes. In the absence of warm season fires when wetlands are dry, shrubs and trees succeed herbaceous plants, which alters wetland productivity via effects on light and detritus quality. We used a factorial aquatic mesocosm study to test the effects of altered detritus and shade on the growth, development, and survival of tadpoles of two priority amphibian species: gopher frogs (Rana capito) and ornate chorus frogs (Pseudacris ornata). Gopher frog survival was higher among maidencane, sedge, and pine treatments compared to oak and sweetgum treatments. While gopher frog larval periods were lowest in the sedge treatment, there was a nominal general effect of litter type on gopher frog larval periods, growth rates, and mass at metamorphosis. Shading had a nominal and inconsistent effect on gopher frog growth rates, but did extend larval periods in all litter treatments, decreased survival in all litter treatments except oak, and decreased mass at metamorphosis in all litter treatments except pine and sweetgum. Ornate chorus frog survival was minimally affected by shading and litter treatments, but growth rates and mass at metamorphosis were highest in maidencane and sedge treatments, and larval periods were extended with shading in all litter treatments. Shading also decreased growth rates in maidencane and sedge litters and decreased mass at metamorphosis in pine and sweetgum litters. Our results demonstrate that succession of isolated wetlands can reduce tadpole performance for two priority species both through changes in leaf litter and shading, though the effect on survival, larval growth, larval period, and size at metamorphosis can differ between species. These results support management recommendations to restore and maintain open canopy, grassy conditions in isolated wetlands for conservation of priority amphibian species.

@techreport{crawford_strategic_2021,
	address = {Athens, Georgia, USA},
	type = {Technical {Report}},
	title = {Strategic conservation management for gopher frogs at site-specific to range-wide scales},
	url = {https://github.com/Maerz-Lab/Integrated-Strategic-Management-for-Gopher-frogs/tree/main/Reports%20and%20Outputs},
	abstract = {We co-developed a gopher frog conservation planning framework with State and federal partners to identify optimal management strategies (combinations of upland and wetland management and headstarting) across 183 focal sites (Fig 1) expected to maximize the number and distribution of breeding populations in 2050 while minimizing cost under different objective tradeoffs (see Table 1). • We combined species data and expert judgment to model links between habitat suitability, breeding frequency, and population persistence (Fig 2) under current conditions and site-specific management options (Table 2) that could be implemented over the next 30 years. • We compared the number of predicted persisting gopher frog populations in 2050 and total costs over the 30-year period across three management scenarios: 1) “Status quo mgmt” where current habitat management continues with no head-starting, 2) “Cost-effective mgmt” where optimal strategies were identified that maximize persistence while minimizing cost, and 3) “Do-all-we-can mgmt” where optimal strategies were identified that maximize persistence regardless of cost. • Results are presented in Table 3 and Fig 4, with an example of site-specific predictions for AL in Fig 3. ◦ Status quo mgmt resulted in 51 predicted persisting populations, on average, and a \$294M base cost. ◦ Cost-effective mgmt resulted in 107 predicted persisting populations and cost \$422M (+ base costs). ◦ Do-all-we-can mgmt resulted in 115 predicted persisting populations and cost \$1,409M (+ base costs). • Under Status quo, Cost-effective, and Do-all-we-can mgmt, the probability of all populations becoming extirpated in at least one conservation unit was {\textgreater}99, 53, and 32\%, respectively (Fig 5). • Partners may use results to evaluate tradeoffs between predicted persistence and cost when selecting management strategies for specific sites and allocating scarce resources across sites to maximize gopher frog outcomes at conservation unit, state-wide, and range-wide scales. • Additional summary tables and figures showing optimal actions and predicted population persistence for each site are available in the project’s Google Drive folder.},
	institution = {University of Georgia},
	author = {Crawford, Brian A. and Maerz, John C.},
	month = apr,
	year = {2021},
}

We co-developed a gopher frog conservation planning framework with State and federal partners to identify optimal management strategies (combinations of upland and wetland management and headstarting) across 183 focal sites (Fig 1) expected to maximize the number and distribution of breeding populations in 2050 while minimizing cost under different objective tradeoffs (see Table 1). • We combined species data and expert judgment to model links between habitat suitability, breeding frequency, and population persistence (Fig 2) under current conditions and site-specific management options (Table 2) that could be implemented over the next 30 years. • We compared the number of predicted persisting gopher frog populations in 2050 and total costs over the 30-year period across three management scenarios: 1) “Status quo mgmt” where current habitat management continues with no head-starting, 2) “Cost-effective mgmt” where optimal strategies were identified that maximize persistence while minimizing cost, and 3) “Do-all-we-can mgmt” where optimal strategies were identified that maximize persistence regardless of cost. • Results are presented in Table 3 and Fig 4, with an example of site-specific predictions for AL in Fig 3. ◦ Status quo mgmt resulted in 51 predicted persisting populations, on average, and a $294M base cost. ◦ Cost-effective mgmt resulted in 107 predicted persisting populations and cost $422M (+ base costs). ◦ Do-all-we-can mgmt resulted in 115 predicted persisting populations and cost $1,409M (+ base costs). • Under Status quo, Cost-effective, and Do-all-we-can mgmt, the probability of all populations becoming extirpated in at least one conservation unit was {\textgreater}99, 53, and 32%, respectively (Fig 5). • Partners may use results to evaluate tradeoffs between predicted persistence and cost when selecting management strategies for specific sites and allocating scarce resources across sites to maximize gopher frog outcomes at conservation unit, state-wide, and range-wide scales. • Additional summary tables and figures showing optimal actions and predicted population persistence for each site are available in the project’s Google Drive folder.

@article{fahey_tracing_2021,
	title = {Tracing carbon flow through a sugar maple forest and its soil components: role of invasive earthworms},
	volume = {464},
	copyright = {All rights reserved},
	issn = {0032-079X, 1573-5036},
	shorttitle = {Tracing carbon flow through a sugar maple forest and its soil components},
	url = {https://link.springer.com/10.1007/s11104-021-04971-4},
	doi = {10.1007/s11104-021-04971-4},
	abstract = {Aims We conducted a suite of tracer studies using the stable isotope 13C to follow and quantify the flow of carbon from leaf litter and roots into soil components including aggregates and biota with and without invasive earthworms.},
	language = {en},
	number = {1-2},
	urldate = {2021-07-07},
	journal = {Plant and Soil},
	author = {Fahey, Timothy and Bohlen, Patrick and Feldpausch, Ted R. and Fisk, Melany and Goebel, Marc and Groffman, Peter M. and Maerz, John and Yavitt, Joseph},
	month = jul,
	year = {2021},
	pages = {517--537},
}

Aims We conducted a suite of tracer studies using the stable isotope 13C to follow and quantify the flow of carbon from leaf litter and roots into soil components including aggregates and biota with and without invasive earthworms.

@article{paulukonis_prioritization_2021,
	title = {Prioritization of {Vulnerable} {Species} {Under} {Scenarios} of {Anthropogenic}-{Driven} {Change} in {Georgia}'s {Coastal} {Plain}},
	volume = {12},
	doi = {10.3996/JFWM-20-089},
	abstract = {Effective management of wildlife populations benefits from an understanding of the long-term vulnerability of species to anthropogenic stressors. Exposure to potential habitat change is one measure of vulnerability that wildlife managers often use to assess and prioritize individual species or groups of species for resource allocation or direct management actions. We used species distribution models for 15 species occurring in the coastal plain ecoregion of Georgia to estimate the current amount and distribution of potential habitat and then predict exposure to changes in habitat due to inundation from sea level rise (using the Sea Level Affecting Marshes model) and urban growth (using the Slope Land-use Excluded Urban Topology Hillshade Growth model) for four future time points. Our results predict that all focal species were likely to experience some exposure to habitat change from either sea level rise or urbanization, but few species will experience high exposure to change from both stressors. Species that use salt marsh or beach habitats had the highest predicted exposure from sea level rise (25–69\%), while species that use more inland habitats had the highest predicted exposure to urban growth (10–20\%). Our models are a resource for managers considering tradeoffs between prioritization schemes under two future stressors. Results suggest that managers may need to prioritize species (or their habitats) based on the predicted magnitude of habitat loss, while also contextualizing prioritization with respect to the current amount of available protected habitat and species global vulnerability.},
	journal = {Journal of Fish and Wildlife Management},
	author = {Paulukonis, Elizabeth and Crawford, Brian and Maerz, John and Wenger, Seth and Nibbelink, Nate},
	month = aug,
	year = {2021},
}

Effective management of wildlife populations benefits from an understanding of the long-term vulnerability of species to anthropogenic stressors. Exposure to potential habitat change is one measure of vulnerability that wildlife managers often use to assess and prioritize individual species or groups of species for resource allocation or direct management actions. We used species distribution models for 15 species occurring in the coastal plain ecoregion of Georgia to estimate the current amount and distribution of potential habitat and then predict exposure to changes in habitat due to inundation from sea level rise (using the Sea Level Affecting Marshes model) and urban growth (using the Slope Land-use Excluded Urban Topology Hillshade Growth model) for four future time points. Our results predict that all focal species were likely to experience some exposure to habitat change from either sea level rise or urbanization, but few species will experience high exposure to change from both stressors. Species that use salt marsh or beach habitats had the highest predicted exposure from sea level rise (25–69%), while species that use more inland habitats had the highest predicted exposure to urban growth (10–20%). Our models are a resource for managers considering tradeoffs between prioritization schemes under two future stressors. Results suggest that managers may need to prioritize species (or their habitats) based on the predicted magnitude of habitat loss, while also contextualizing prioritization with respect to the current amount of available protected habitat and species global vulnerability.

@article{demi_experimental_2020,
	title = {Experimental {N} and {P} additions relieve stoichiometric constraints on organic-matter flows through five stream food webs},
	copyright = {All rights reserved},
	doi = {10.1111/1365-2656.13197},
	abstract = {Este documento examina el concepto de comunicaciones integradas de marketing, a través de la revisión de las diferentes conceptuali - zaciones y los modelos...},
	number = {2020},
	journal = {Journal of Animal Ecology},
	author = {Demi, Lee M. and Benstead, Jonathan P. and Rosemond, Amy D. and Maerz, John C.},
	year = {2020},
	keywords = {al, department of biological sciences, odum school of ecology, tuscaloosa, university of, university of alabama, usa},
	pages = {1--14},
}

Este documento examina el concepto de comunicaciones integradas de marketing, a través de la revisión de las diferentes conceptuali - zaciones y los modelos...

@article{stiles_density-dependent_2020,
	title = {Density-{Dependent} {Fitness} {Attributes} and {Carry}-{Over} {Effects} in {Crawfish} {Frogs} ({Rana} areolata), a {Species} of {Conservation} {Concern}},
	volume = {108},
	copyright = {All rights reserved},
	issn = {0045-8511},
	url = {https://bioone.org/journals/copeia/volume-108/issue-3/CH-19-246/Density-Dependent-Fitness-Attributes-and-Carry-Over-Effects-in-Crawfish/10.1643/CH-19-246.full},
	doi = {10.1643/CH-19-246},
	abstract = {Fitness attributes acquired in aquatic habitats by amphibians exhibiting complex life histories have been shown to cascade through terrestrial juveniles into adulthood, a phenomenon termed carry-over effects. We explored density-dependent fitness attributes and carry-over effects in Crawfish Frogs (Rana areolata) using a set of field enclosure experiments and a series of field data. Using field enclosures, we hypothesized that 1) at high densities, intraspecific competition would produce smaller Crawfish Frog juveniles that took longer to metamorphose; 2) at high densities, interspecific competition would also produce smaller Crawfish Frog juveniles that took longer to metamorphose; and 3) vertebrate (ambystomatid salamander) predation on Crawfish Frog larvae would reduce survivorship, but by releasing competition pressure would produce relatively larger tadpoles that metamorphosed earlier. Further, we hypothesized 4) that these enclosure results would apply to field data, and that fitness attributes in newly metamorphosed Crawfish Frogs would carry over to first-time breeding adults. Our results confirmed all four hypotheses. Specifically, in Crawfish Frogs, at high densities, both intra- and interspecific competition reduced size (length and mass) at metamorphosis (hypotheses 1 and 2), and predation reduced survivorship and increased size at metamorphosis (hypothesis 3). Finally, we observed density-dependent fitness effects on newly metamorphosed Crawfish Frog juvenile size (length and mass), and carry-over effects from the larval stage on juvenile survival, adult size, and breeding adult numbers (hypothesis 4). In the absence of predators, high densities of intra- and interspecific competitors had no effect on Crawfish Frog larval survivorship. We also present suggestive evidence for compensatory effects. We discuss the potential mechanisms underlying the patterns of these interactions, as well as the role of these relationships in informing management guidelines intended to ensure the future of this species of conservation concern.},
	language = {en},
	number = {3},
	urldate = {2020-07-22},
	journal = {Copeia},
	author = {Stiles, Rochelle M. and Terrell, Vanessa C. K. and Maerz, John C. and Lannoo, Michael J.},
	month = jul,
	year = {2020},
	pages = {443--452},
}

Fitness attributes acquired in aquatic habitats by amphibians exhibiting complex life histories have been shown to cascade through terrestrial juveniles into adulthood, a phenomenon termed carry-over effects. We explored density-dependent fitness attributes and carry-over effects in Crawfish Frogs (Rana areolata) using a set of field enclosure experiments and a series of field data. Using field enclosures, we hypothesized that 1) at high densities, intraspecific competition would produce smaller Crawfish Frog juveniles that took longer to metamorphose; 2) at high densities, interspecific competition would also produce smaller Crawfish Frog juveniles that took longer to metamorphose; and 3) vertebrate (ambystomatid salamander) predation on Crawfish Frog larvae would reduce survivorship, but by releasing competition pressure would produce relatively larger tadpoles that metamorphosed earlier. Further, we hypothesized 4) that these enclosure results would apply to field data, and that fitness attributes in newly metamorphosed Crawfish Frogs would carry over to first-time breeding adults. Our results confirmed all four hypotheses. Specifically, in Crawfish Frogs, at high densities, both intra- and interspecific competition reduced size (length and mass) at metamorphosis (hypotheses 1 and 2), and predation reduced survivorship and increased size at metamorphosis (hypothesis 3). Finally, we observed density-dependent fitness effects on newly metamorphosed Crawfish Frog juvenile size (length and mass), and carry-over effects from the larval stage on juvenile survival, adult size, and breeding adult numbers (hypothesis 4). In the absence of predators, high densities of intra- and interspecific competitors had no effect on Crawfish Frog larval survivorship. We also present suggestive evidence for compensatory effects. We discuss the potential mechanisms underlying the patterns of these interactions, as well as the role of these relationships in informing management guidelines intended to ensure the future of this species of conservation concern.

@article{crawford_expert-informed_2020,
	title = {Expert-{Informed} {Habitat} {Suitability} {Analysis} for {At}-{Risk} {Species} {Assessment} and {Conservation} {Planning}},
	volume = {11},
	issn = {1944-687X},
	url = {https://meridian.allenpress.com/jfwm/article/11/1/130/436152/Expert-Informed-Habitat-Suitability-Analysis-for},
	doi = {10.3996/092019-JFWM-075},
	abstract = {The U.S. Fish and Wildlife Service (USFWS) is responsible for reviewing the biological status of hundreds of species to determine federal status designations under the Endangered Species Act. The longleaf pine Pinus palustris ecological system supports many priority at-risk species designated for review, including five species of herpetofauna: gopher tortoise Gopherus polyphemus, southern hognose snake Heterodon simus, Florida pine snake Pituophis melanoleucus mugitus, gopher frog Lithobates (Rana) capito, and striped newt Notophthalmus perstriatus. To inform status decisions and conservation planning, we developed habitat suitability models to 1) identify habitat features that best predict species presence and 2) estimate the amount and distribution of suitable habitat across each species’ range under current conditions. We incorporated expert judgment from federal, state, and other partners to capture variation in ecological settings across species’ ranges, prioritize predictor variables to test in models, mitigate data limitations by informing the selection of pseudoabsence points, qualitatively evaluate model estimates, and improve the likelihood that experts will trust and use model predictions for conservation. Soil characteristics, land cover, and fire interval strongly influenced habitat suitability for all species. Suitable habitat was distributed on known species strongholds, as well as private lands without known species records. Between 4.7\% (gopher frog) and 14.6\% (gopher tortoise) of the area in a species’ range was classified as suitable habitat, and between 28.1\% (southern hognose snake) and 47.5\% (gopher frog) of suitable habitat was located in patches larger than 1 km2 (100 ha) on publicly owned lands. By overlaying predictions for each species, we identified areas of suitable habitat for multiple species on protected and unprotected lands. These results have direct applications to management and conservation planning: partners can tailor site-level management based on attributes associated with high habitat suitability for species of concern; allocate survey effort in areas with suitable habitat but no known species records; and identify priority areas for management, land acquisitions, or other strategies based on the distribution of species records, suitable habitat, and land protection status. These results can aid regional partners in implementing effective conservation strategies and inform status designation decisions of the USFWS.},
	language = {en},
	number = {1},
	urldate = {2022-10-05},
	journal = {Journal of Fish and Wildlife Management},
	author = {Crawford, Brian A. and Maerz, John C. and Moore, Clinton T.},
	month = jun,
	year = {2020},
	pages = {130--150},
}

The U.S. Fish and Wildlife Service (USFWS) is responsible for reviewing the biological status of hundreds of species to determine federal status designations under the Endangered Species Act. The longleaf pine Pinus palustris ecological system supports many priority at-risk species designated for review, including five species of herpetofauna: gopher tortoise Gopherus polyphemus, southern hognose snake Heterodon simus, Florida pine snake Pituophis melanoleucus mugitus, gopher frog Lithobates (Rana) capito, and striped newt Notophthalmus perstriatus. To inform status decisions and conservation planning, we developed habitat suitability models to 1) identify habitat features that best predict species presence and 2) estimate the amount and distribution of suitable habitat across each species’ range under current conditions. We incorporated expert judgment from federal, state, and other partners to capture variation in ecological settings across species’ ranges, prioritize predictor variables to test in models, mitigate data limitations by informing the selection of pseudoabsence points, qualitatively evaluate model estimates, and improve the likelihood that experts will trust and use model predictions for conservation. Soil characteristics, land cover, and fire interval strongly influenced habitat suitability for all species. Suitable habitat was distributed on known species strongholds, as well as private lands without known species records. Between 4.7% (gopher frog) and 14.6% (gopher tortoise) of the area in a species’ range was classified as suitable habitat, and between 28.1% (southern hognose snake) and 47.5% (gopher frog) of suitable habitat was located in patches larger than 1 km2 (100 ha) on publicly owned lands. By overlaying predictions for each species, we identified areas of suitable habitat for multiple species on protected and unprotected lands. These results have direct applications to management and conservation planning: partners can tailor site-level management based on attributes associated with high habitat suitability for species of concern; allocate survey effort in areas with suitable habitat but no known species records; and identify priority areas for management, land acquisitions, or other strategies based on the distribution of species records, suitable habitat, and land protection status. These results can aid regional partners in implementing effective conservation strategies and inform status designation decisions of the USFWS.

@article{crawford_estimating_2020,
	title = {Estimating population persistence for at-risk species using citizen science data},
	volume = {243},
	copyright = {All rights reserved},
	url = {https://doi.org/10.1016/j.biocon.2020.108489},
	doi = {10.1016/j.biocon.2020.108489},
	abstract = {Population persistence probability is valuable for characterizing risk to species and informing listing and conservation decisions but is challenging to estimate through traditional methods for rare, data-limited species. Modeling approaches have used citizen science data to mitigate data limitations of focal species and better estimate parameters such as occupancy and detection, but their use to estimate persistence and inform conservation decisions is limited. We developed an approach to estimate persistence using only occurrence records of the target species and citizen science occurrence data of non-target species to account for search effort and imperfect detection. We applied the approach to a highly cryptic and data-limited species, the southern hognose snake (Heterodon simus), as part of its USFWS Species Status Assessment, and estimated current (in 2018) and future persistence under plausible scenarios of varying levels of urbanization, sea level rise, and management. Of 222 known populations, 133 (60\%) are likely extirpated currently (persistence probability {\textless} 50\%), and 165 (74\%) populations are likely to be extirpated by 2080 with no additional management. Future management scenarios that included strategies to acquire and improve habitat on currently unprotected lands with existing populations lessened the estimated rate of population declines. These results can directly inform listing decisions and conservation planning for the southern hognose snake by Federal, State, and other partners. Our approach – using occurrence records and auxiliary data from non-target species to estimate population persistence – is applicable across rare and at-risk species for evaluating extinction risk with limited data and prioritizing management actions.},
	number = {September 2019},
	journal = {Biological Conservation},
	author = {Crawford, Brian A. and Olds, Melanie J. and Maerz, John C. and Moore, Clinton T.},
	year = {2020},
	note = {Publisher: Elsevier},
	keywords = {Bayesian inference, Conservation planning, Endangered species listing decisions, Extinction probability, HerpMapper, Occurrence records, Southern hognose snake, Species status assessment},
	pages = {108489--108489},
}

Population persistence probability is valuable for characterizing risk to species and informing listing and conservation decisions but is challenging to estimate through traditional methods for rare, data-limited species. Modeling approaches have used citizen science data to mitigate data limitations of focal species and better estimate parameters such as occupancy and detection, but their use to estimate persistence and inform conservation decisions is limited. We developed an approach to estimate persistence using only occurrence records of the target species and citizen science occurrence data of non-target species to account for search effort and imperfect detection. We applied the approach to a highly cryptic and data-limited species, the southern hognose snake (Heterodon simus), as part of its USFWS Species Status Assessment, and estimated current (in 2018) and future persistence under plausible scenarios of varying levels of urbanization, sea level rise, and management. Of 222 known populations, 133 (60%) are likely extirpated currently (persistence probability \textless 50%), and 165 (74%) populations are likely to be extirpated by 2080 with no additional management. Future management scenarios that included strategies to acquire and improve habitat on currently unprotected lands with existing populations lessened the estimated rate of population declines. These results can directly inform listing decisions and conservation planning for the southern hognose snake by Federal, State, and other partners. Our approach – using occurrence records and auxiliary data from non-target species to estimate population persistence – is applicable across rare and at-risk species for evaluating extinction risk with limited data and prioritizing management actions.

@article{gade_predicted_2020,
	title = {Predicted alteration of surface activity as a consequence of climate change},
	volume = {101},
	copyright = {All rights reserved},
	issn = {0012-9658, 1939-9170},
	url = {https://onlinelibrary.wiley.com/doi/10.1002/ecy.3154},
	doi = {10.1002/ecy.3154},
	abstract = {Wildlife are faced with numerous threats to survival, none more pressing than that of climate change. Understanding how species will respond behaviorally, physiologically, and demographically to a changing climate is a cornerstone of many contemporary ecological studies, especially for organisms, such as amphibians, whose persistence is closely tied to abiotic conditions. Activity is a useful parameter for understanding the effects of climate change because activity is directly linked to fitness as it dictates foraging times, energy budgets, and mating opportunities. However, activity can be challenging to measure directly, especially for secretive organisms like plethodontid salamanders, which only become surface active when conditions are cool and moist because of their anatomical and physiological restrictions. We estimated abiotic predictors of surface activity for the seven species of the Plethodon jordani complex. Five independent data sets collected from 2004 to 2017 were used to determine the parameters driving salamander surface activity in the present day, which were then used to predict potential activity changes over the next 80 yrs. Average active seasonal temperature and vapor pressure deficit were the strongest predictors of salamander surface activity and, without physiological or behavioral modifications, salamanders were predicted to exhibit a higher probability of surface activity during peak active season under future climate conditions. Temperatures during the active season likely do not exceed salamander thermal maxima to cause activity suppression and, until physiological limits are reached, future conditions may continue to increase activity. Our model is the first comprehensive field-based study to assess current and future surface activity probability. Our study provides insights into how a key behavior driving fitness may be affected by climate change.},
	language = {en},
	number = {11},
	urldate = {2021-07-07},
	journal = {Ecology},
	author = {Gade, Meaghan R. and Connette, Grant M. and Crawford, John A. and Hocking, Daniel J. and Maerz, John C. and Milanovich, Joseph R. and Peterman, William E.},
	month = nov,
	year = {2020},
}

Wildlife are faced with numerous threats to survival, none more pressing than that of climate change. Understanding how species will respond behaviorally, physiologically, and demographically to a changing climate is a cornerstone of many contemporary ecological studies, especially for organisms, such as amphibians, whose persistence is closely tied to abiotic conditions. Activity is a useful parameter for understanding the effects of climate change because activity is directly linked to fitness as it dictates foraging times, energy budgets, and mating opportunities. However, activity can be challenging to measure directly, especially for secretive organisms like plethodontid salamanders, which only become surface active when conditions are cool and moist because of their anatomical and physiological restrictions. We estimated abiotic predictors of surface activity for the seven species of the Plethodon jordani complex. Five independent data sets collected from 2004 to 2017 were used to determine the parameters driving salamander surface activity in the present day, which were then used to predict potential activity changes over the next 80 yrs. Average active seasonal temperature and vapor pressure deficit were the strongest predictors of salamander surface activity and, without physiological or behavioral modifications, salamanders were predicted to exhibit a higher probability of surface activity during peak active season under future climate conditions. Temperatures during the active season likely do not exceed salamander thermal maxima to cause activity suppression and, until physiological limits are reached, future conditions may continue to increase activity. Our model is the first comprehensive field-based study to assess current and future surface activity probability. Our study provides insights into how a key behavior driving fitness may be affected by climate change.

@article{demi_experimental_2019,
	title = {Experimental {N} and {P} additions alter stream macroinvertebrate community composition via taxon-level responses to shifts in detrital resource stoichiometry},
	copyright = {All rights reserved},
	doi = {10.1111/1365-2435.13289},
	abstract = {Summary 1.Increases in nitrogen (N) and phosphorus (P) availability are changing animal communities, partly by altering stoichiometric imbalances between consumers and their food. Testing relationships between resource stoichiometry and consumer assemblage structure requires ecosystem‐level manipulations that have been lacking to date. 2.We analyzed patterns of macroinvertebrate community composition in five detritus‐based headwater streams subject to experimental whole‐stream N and P additions that spanned a steep gradient in dissolved N:P ratio (2:1, 8:1, 16:1, 32:1, 128:1) over two years, following a one‐year pre‐treatment period. 3.We predicted that shifts in leaf litter stoichiometry would drive overall patterns of community composition via greater responses of shredders to enrichment than other taxa, as shredders dominate primary consumer biomass and experience larger consumer‐resource elemental imbalances than other functional groups in stream ecosystems. Specifically, we expected litter C:P to be a significant predictor of shredder biomass given the greater relative imbalances between shredder and litter C:P than C:N. Finally, we tested whether shredder responses to enrichment were related to other taxon‐level traits, including body size and stoichiometry, larval lifespan and growth rate. 4.Whole‐community composition shifted similarly across the five streams after enrichment, largely driven by increased shredder and predator biomass. These shifts were limited to the autumn/winter seasons and related to decreased leaf litter C:P, highlighting important links between the quality of seasonal litter subsidies and community phenology. 5.Among 10 taxa that drove structural shifts, two declined while other taxa from the same functional/taxonomic groups responded positively, suggesting that specific life‐history traits may determine sensitivity to enrichment. 6.Increases in total shredder biomass, and in biomass of several common shredders, were associated with lower litter C:P. Body C:P did not predict shredder response to enrichment. However, weak negative relationships between shredder response and body size, and larval lifespan, suggest that small‐bodied and short‐lived taxa may be more responsive to shifting resource stoichiometry. 7.Moderate anthropogenic increases in N and P availability affect resource stoichiometry and can alter animal communities, influencing additional food‐web and ecosystem properties. We provide support for ecological stoichiometry as a framework for predicting such outcomes based on changes in the elemental composition of resource pools. This article is protected by copyright. All rights reserved.},
	number = {2019},
	journal = {Functional Ecology},
	author = {Demi, Lee M. and Benstead, Jonathan P. and Rosemond, Amy D. and Maerz, John C.},
	year = {2019},
	pages = {1--13},
}

Summary 1.Increases in nitrogen (N) and phosphorus (P) availability are changing animal communities, partly by altering stoichiometric imbalances between consumers and their food. Testing relationships between resource stoichiometry and consumer assemblage structure requires ecosystem‐level manipulations that have been lacking to date. 2.We analyzed patterns of macroinvertebrate community composition in five detritus‐based headwater streams subject to experimental whole‐stream N and P additions that spanned a steep gradient in dissolved N:P ratio (2:1, 8:1, 16:1, 32:1, 128:1) over two years, following a one‐year pre‐treatment period. 3.We predicted that shifts in leaf litter stoichiometry would drive overall patterns of community composition via greater responses of shredders to enrichment than other taxa, as shredders dominate primary consumer biomass and experience larger consumer‐resource elemental imbalances than other functional groups in stream ecosystems. Specifically, we expected litter C:P to be a significant predictor of shredder biomass given the greater relative imbalances between shredder and litter C:P than C:N. Finally, we tested whether shredder responses to enrichment were related to other taxon‐level traits, including body size and stoichiometry, larval lifespan and growth rate. 4.Whole‐community composition shifted similarly across the five streams after enrichment, largely driven by increased shredder and predator biomass. These shifts were limited to the autumn/winter seasons and related to decreased leaf litter C:P, highlighting important links between the quality of seasonal litter subsidies and community phenology. 5.Among 10 taxa that drove structural shifts, two declined while other taxa from the same functional/taxonomic groups responded positively, suggesting that specific life‐history traits may determine sensitivity to enrichment. 6.Increases in total shredder biomass, and in biomass of several common shredders, were associated with lower litter C:P. Body C:P did not predict shredder response to enrichment. However, weak negative relationships between shredder response and body size, and larval lifespan, suggest that small‐bodied and short‐lived taxa may be more responsive to shifting resource stoichiometry. 7.Moderate anthropogenic increases in N and P availability affect resource stoichiometry and can alter animal communities, influencing additional food‐web and ecosystem properties. We provide support for ecological stoichiometry as a framework for predicting such outcomes based on changes in the elemental composition of resource pools. This article is protected by copyright. All rights reserved.

@article{frelich_sideswiped_2019,
	title = {Side‐swiped: ecological cascades emanating from earthworm invasions},
	volume = {17},
	issn = {1540-9295, 1540-9309},
	shorttitle = {Side‐swiped},
	url = {https://onlinelibrary.wiley.com/doi/10.1002/fee.2099},
	doi = {10.1002/fee.2099},
	abstract = {Non-native, invasive earthworms are altering soils throughout the world. Ecological cascades emanating from these invasions stem from rapid consumption of leaf litter by earthworms. This occurs at a midpoint in the trophic pyramid, unlike the more familiar bottom-up or top-down cascades. These cascades cause fundamental changes (“microcascade effects”) in soil morphology, bulk density, and nutrient leaching, and a shift to warmer, drier soil surfaces with a loss of leaf litter. In North American temperate and boreal forests, microcascade effects can affect carbon sequestration, disturbance regimes, soil and water quality, forest productivity, plant communities, and wildlife habitat, and can facilitate other invasive species. These broader-scale changes (“macrocascade effects”) are of greater concern to society. Interactions among these fundamental changes and broader-scale effects create “cascade complexes” that interact with climate change and other environmental processes. The diversity of cascade effects, combined with the vast area invaded by earthworms, leads to regionally important changes in ecological functioning.},
	language = {en},
	number = {9},
	urldate = {2022-04-13},
	journal = {Frontiers in Ecology and the Environment},
	author = {Frelich, Lee E and Blossey, Bernd and Cameron, Erin K and Dávalos, Andrea and Eisenhauer, Nico and Fahey, Timothy and Ferlian, Olga and Groffman, Peter M and Larson, Evan and Loss, Scott R and Maerz, John C and Nuzzo, Victoria and Yoo, Kyungsoo and Reich, Peter B},
	month = nov,
	year = {2019},
	pages = {502--510},
}

Non-native, invasive earthworms are altering soils throughout the world. Ecological cascades emanating from these invasions stem from rapid consumption of leaf litter by earthworms. This occurs at a midpoint in the trophic pyramid, unlike the more familiar bottom-up or top-down cascades. These cascades cause fundamental changes (“microcascade effects”) in soil morphology, bulk density, and nutrient leaching, and a shift to warmer, drier soil surfaces with a loss of leaf litter. In North American temperate and boreal forests, microcascade effects can affect carbon sequestration, disturbance regimes, soil and water quality, forest productivity, plant communities, and wildlife habitat, and can facilitate other invasive species. These broader-scale changes (“macrocascade effects”) are of greater concern to society. Interactions among these fundamental changes and broader-scale effects create “cascade complexes” that interact with climate change and other environmental processes. The diversity of cascade effects, combined with the vast area invaded by earthworms, leads to regionally important changes in ecological functioning.

@article{mcentire_integrating_2019,
	title = {Integrating ecophysiological and agent-based models to simulate how behavior moderates salamander sensitivity to climate},
	volume = {7},
	copyright = {All rights reserved},
	doi = {10.3389/fevo.2019.00022},
	abstract = {Developing rigorous ecological models is a fundamental goal of conservation biologists seeking to forecast biotic responses to climate change. A limitation of many models is they are amechanistic and lack integration of behavior, which is fundamental to animal biology. We integrated biophysical and agent-based models (ABM) to examine how behavior could affect the sensitivity of Plethodontid salamander activity time to climate. Specifically, our model used a temperature differential to stimulate plant climbing, a widely observed behavior among salamanders, which would allow salamanders to reduce body temperatures and associated dehydration rates. Consistent with expectations, predicted activity time was positively correlated with precipitation. The model showed that climbing plants increased activity time in drier conditions, particularly for smaller salamanders. The predicted importance of climbing behavior, a form of behavioral plasticity, was highly sensitive to assumptions about the threshold of water loss an individual was willing to tolerate. Because activity time is associated with fitness, increased activity time as a consequence of climbing behavior could moderate salamander sensitivity to shifts in weather patterns. Our results demonstrate the potential and importance of integrating behaviors into ecophysiological models when evaluating a species’ potential sensitivity to climate. Keywords:},
	number = {February},
	journal = {Frontiers in Ecology and the Environment},
	author = {McEntire, Kira D. and Maerz, John C},
	year = {2019},
	keywords = {amphibian, conservation, ecology, individual-based models, management},
	pages = {1--10},
}

Developing rigorous ecological models is a fundamental goal of conservation biologists seeking to forecast biotic responses to climate change. A limitation of many models is they are amechanistic and lack integration of behavior, which is fundamental to animal biology. We integrated biophysical and agent-based models (ABM) to examine how behavior could affect the sensitivity of Plethodontid salamander activity time to climate. Specifically, our model used a temperature differential to stimulate plant climbing, a widely observed behavior among salamanders, which would allow salamanders to reduce body temperatures and associated dehydration rates. Consistent with expectations, predicted activity time was positively correlated with precipitation. The model showed that climbing plants increased activity time in drier conditions, particularly for smaller salamanders. The predicted importance of climbing behavior, a form of behavioral plasticity, was highly sensitive to assumptions about the threshold of water loss an individual was willing to tolerate. Because activity time is associated with fitness, increased activity time as a consequence of climbing behavior could moderate salamander sensitivity to shifts in weather patterns. Our results demonstrate the potential and importance of integrating behaviors into ecophysiological models when evaluating a species’ potential sensitivity to climate. Keywords:

@incollection{durso_natural_2019,
	edition = {3rd},
	title = {Natural {Behaviors}},
	copyright = {All rights reserved},
	booktitle = {Mader’s {Reptile} and {Amphibian} {Medicine}, 3rd {Edition}},
	publisher = {Elsevier},
	author = {Durso, Andrew M. and Maerz, John C.},
	editor = {Divers, S. and Stahl, S.},
	year = {2019},
}

@incollection{chambers_terrapin_2019,
	title = {Terrapin {Conservation}: {Fisheries} {Bycatch}},
	copyright = {All rights reserved},
	booktitle = {The {Ecology} and {Management} of {Diamondback} {Terrapins}},
	publisher = {Johns Hopkins University Press},
	author = {Chambers, Randolph M. and Maerz, John C.},
	editor = {Roosenburg, Willem M. and Kennedy, Victor S.},
	year = {2019},
	keywords = {bycatch},
	pages = {187--200},
}

@article{maerz_seasonal_2019,
	title = {Seasonal and plant specific vulnerability of amphibian tadpoles to the invasion of a novel cyanobacteria},
	volume = {21},
	copyright = {All rights reserved},
	issn = {1387-3547 1573-1464},
	doi = {10.1007/s10530-018-1861-6},
	abstract = {Aetokthonos hydrillicola (Ah) is a newly described cyanobacteria that forms dense colonies on aquatic macrophytes, primarily invasive Hydrilla verticillata, and is associated with mortality of fresh- water wildlife. Prior research shows that Ah growing on Hydrilla is potently toxic to waterbirds, turtles, and fish, suggesting potentially broad sensitivity among vertebrates. We tested whether amphibian tadpole species were affected by ingestion of Ah-positive Hydrilla, and whether season, host plant, or tadpole age/size affected tadpole vulnerability. For trials involving ranid tadpoles (Bullfrogs, Rana cates- beiana; Green frogs, R. clamitans; and Southern leopard frogs, R. sphenocephala), feeding on Ah- positive Hydrilla collected during October–November resulted in the development of lesions within brain tissue and significant mortality. Ranid tadpole sensi- tivity to Ah toxin did not vary with age or size, but vulnerability from ingestion of Ah-positive Hydrilla varied seasonally and between two syntopic host plants. An unexpected result of our study was the apparent insensitivity of Green treefrog tadpoles (Hyla cinerea) fed toxic, Ah-positive Hydrilla. In conjunc- tion with other studies, our results confirm wide but variable sensitivity among major vertebrate lineages to the Ah toxin. Differential sensitivity among species means that the introduction of Ah could alter intinteractions and structure within aquatic communities.},
	number = {3},
	journal = {Biological Invasions},
	author = {Maerz, John C and Wilde, Susan B and Terrell, Vanessa K and Haram, Brigette and Trimmer, R Clay and Nunez, Chelsea and Cork, Erin and Pessier, Allan and Lannoo, Sue and Lannoo, Michael J and Diamond, Sara L},
	year = {2019},
	pages = {821--831},
}

Aetokthonos hydrillicola (Ah) is a newly described cyanobacteria that forms dense colonies on aquatic macrophytes, primarily invasive Hydrilla verticillata, and is associated with mortality of fresh- water wildlife. Prior research shows that Ah growing on Hydrilla is potently toxic to waterbirds, turtles, and fish, suggesting potentially broad sensitivity among vertebrates. We tested whether amphibian tadpole species were affected by ingestion of Ah-positive Hydrilla, and whether season, host plant, or tadpole age/size affected tadpole vulnerability. For trials involving ranid tadpoles (Bullfrogs, Rana cates- beiana; Green frogs, R. clamitans; and Southern leopard frogs, R. sphenocephala), feeding on Ah- positive Hydrilla collected during October–November resulted in the development of lesions within brain tissue and significant mortality. Ranid tadpole sensi- tivity to Ah toxin did not vary with age or size, but vulnerability from ingestion of Ah-positive Hydrilla varied seasonally and between two syntopic host plants. An unexpected result of our study was the apparent insensitivity of Green treefrog tadpoles (Hyla cinerea) fed toxic, Ah-positive Hydrilla. In conjunc- tion with other studies, our results confirm wide but variable sensitivity among major vertebrate lineages to the Ah toxin. Differential sensitivity among species means that the introduction of Ah could alter intinteractions and structure within aquatic communities.

@incollection{maerz_terrapin_2019,
	title = {Terrapin {Conservation}: {Mitigating} {Habitat} {Loss}, {Road} {Mortality}, and {Subsidized} {Predators}},
	copyright = {All rights reserved},
	booktitle = {The {Ecology} and {Management} of {Diamondback} {Terrapins}},
	publisher = {Johns Hopkins University Press},
	author = {Maerz, John C. and Seigel, Richard A. and Crawford, Brian A.},
	editor = {Roosenburg, Willem M. and Kennedy, Victor S.},
	year = {2019},
	keywords = {Malaclemys terrapin},
	pages = {201--220},
}

@article{satterfield_migratory_2018,
	title = {Migratory monarchs that encounter resident monarchs show life-history differences and higher rates of parasite infection},
	volume = {21},
	copyright = {All rights reserved},
	issn = {1461-0248 (Electronic) 1461-023X (Linking)},
	url = {https://www.ncbi.nlm.nih.gov/pubmed/30152196},
	doi = {10.1111/ele.13144},
	abstract = {Environmental change induces some wildlife populations to shift from migratory to resident behaviours. Newly formed resident populations could influence the health and behaviour of remaining migrants. We investigated migrant-resident interactions among monarch butterflies and consequences for life history and parasitism. Eastern North American monarchs migrate annually to Mexico, but some now breed year-round on exotic milkweed in the southern US and experience high infection prevalence of protozoan parasites. Using stable isotopes (delta(2) H, delta(13) C) and cardenolide profiles to estimate natal origins, we show that migrant and resident monarchs overlap during fall and spring migration. Migrants at sites with residents were 13 times more likely to have infections and three times more likely to be reproductive (outside normal breeding season) compared to other migrants. Exotic milkweed might either attract migrants that are already infected or reproductive, or alternatively, induce these states. Increased migrant-resident interactions could affect monarch parasitism, migratory success and long-term conservation.},
	journal = {Ecology Letters},
	author = {Satterfield, D A and Maerz, J C and Hunter, M D and Flockhart, D T T and Hobson, K A and Norris, D R and Streit, H and de Roode, J C and Altizer, S},
	year = {2018},
	note = {Edition: 2018/08/29},
	keywords = {Asclepias curassavica, Danaus plexippus, Ophryocystis elektroscirrha, cardenolide profile, migrant-resident interactions, partial migration, reproductive diapause, stable isotopes, tropical milkweed},
	pages = {1670--1680},
}

Environmental change induces some wildlife populations to shift from migratory to resident behaviours. Newly formed resident populations could influence the health and behaviour of remaining migrants. We investigated migrant-resident interactions among monarch butterflies and consequences for life history and parasitism. Eastern North American monarchs migrate annually to Mexico, but some now breed year-round on exotic milkweed in the southern US and experience high infection prevalence of protozoan parasites. Using stable isotopes (delta(2) H, delta(13) C) and cardenolide profiles to estimate natal origins, we show that migrant and resident monarchs overlap during fall and spring migration. Migrants at sites with residents were 13 times more likely to have infections and three times more likely to be reproductive (outside normal breeding season) compared to other migrants. Exotic milkweed might either attract migrants that are already infected or reproductive, or alternatively, induce these states. Increased migrant-resident interactions could affect monarch parasitism, migratory success and long-term conservation.

@article{camp_life_2018,
	title = {Life history and habitat of the rare {Patch}-{Nosed} {Salamander} ({Urspelerpes} bruceii)},
	volume = {13},
	copyright = {All rights reserved},
	abstract = {We examined the life history and habitat characteristics for the Patch-nosed Salamander, Urspelerpes brucei. Body-size measurements of individuals captured using litter bags and by hand from 2008 to 2010 indicated that the larval period lasts at least 2 y, salamanders attain reproductive maturity at or shortly after metamorphosis, and adults have very little variation in body size. Occupied streams are characterized by small size, little water, and narrow, steep-walled ravines. Within occupied streams, larval capture rate was significantly and negatively related to mean water depth, underscoring the importance of protecting headwaters. We hypothesize that the only known population of U. brucei east of the Tugaloo River was isolated from the west-bank populations by the tremendous increase in water flow caused by the capture of the Tallulah and Chattooga rivers by the Tugaloo as recently as the Pleistocene.},
	number = {3},
	journal = {HERPETOLOGICAL CONSERVATION AND BIOLOGY},
	author = {Camp, Carlos D and Brock, Tyler L. and Pierson, Todd W and Milanovich, Joseph R. and Maerz, John C.},
	year = {2018},
	keywords = {amphibian, development, headwater, larvae, metamorphosis, plethodontid, salamander, stream capture},
	pages = {609--616},
}

We examined the life history and habitat characteristics for the Patch-nosed Salamander, Urspelerpes brucei. Body-size measurements of individuals captured using litter bags and by hand from 2008 to 2010 indicated that the larval period lasts at least 2 y, salamanders attain reproductive maturity at or shortly after metamorphosis, and adults have very little variation in body size. Occupied streams are characterized by small size, little water, and narrow, steep-walled ravines. Within occupied streams, larval capture rate was significantly and negatively related to mean water depth, underscoring the importance of protecting headwaters. We hypothesize that the only known population of U. brucei east of the Tugaloo River was isolated from the west-bank populations by the tremendous increase in water flow caused by the capture of the Tallulah and Chattooga rivers by the Tugaloo as recently as the Pleistocene.

@article{crawford_integrated_2018,
	title = {Integrated analysis for population estimation, management impact evaluation, and decision-making for a declining species},
	volume = {222},
	copyright = {All rights reserved},
	doi = {10.1016/j.biocon.2018.03.023},
	abstract = {A challenge for making conservation decisions is predicting how wildlife populations respond to multiple, concurrent threats and potential management strategies, usually under substantial uncertainty. Integrated modeling approaches can improve estimation of demographic rates necessary for making predictions, even for rare or cryptic species with sparse data, but their use in management applications is limited. We developed integrated models for a population of diamondback terrapins (Malaclemys terrapin) impacted by road-associated threats to (i) jointly estimate demographic rates from two mark-recapture datasets, while directly estimating road mortality and the impact of management actions deployed during the study; and (ii) project the population using population viability analysis under simulated management strategies to inform decision-making. Without management, population extirpation was nearly certain due to demographic impacts of road mortality, predators, and vegetation. Installation of novel flashing signage increased survival of terrapins that crossed roads by 30\%. Signage, along with small roadside barriers installed during the study, increased population persistence probability, but the population was still predicted to decline. Management strategies that included actions targeting multiple threats and demographic rates resulted in the highest persistence probability, and roadside barriers, which increased adult survival, were predicted to increase persistence more than other actions. Our results support earlier findings showing mitigation of multiple threats is likely required to increase the viability of declining populations. Our approach illustrates how integrated models may be adapted to use limited data efficiently, represent system complexity, evaluate impacts of threats and management actions, and provide decision-relevant information for conservation of at-risk populations.},
	journal = {Biological Conservation},
	author = {Crawford, Brian A. and Moore, Clinton T. and Norton, Terry M. and Maerz, John C.},
	year = {2018},
	keywords = {Bayesian inference, Diamondback terrapin, Mark-recapture, Multistate model, Population viability analysis, Road mortality},
	pages = {33--43},
}

A challenge for making conservation decisions is predicting how wildlife populations respond to multiple, concurrent threats and potential management strategies, usually under substantial uncertainty. Integrated modeling approaches can improve estimation of demographic rates necessary for making predictions, even for rare or cryptic species with sparse data, but their use in management applications is limited. We developed integrated models for a population of diamondback terrapins (Malaclemys terrapin) impacted by road-associated threats to (i) jointly estimate demographic rates from two mark-recapture datasets, while directly estimating road mortality and the impact of management actions deployed during the study; and (ii) project the population using population viability analysis under simulated management strategies to inform decision-making. Without management, population extirpation was nearly certain due to demographic impacts of road mortality, predators, and vegetation. Installation of novel flashing signage increased survival of terrapins that crossed roads by 30%. Signage, along with small roadside barriers installed during the study, increased population persistence probability, but the population was still predicted to decline. Management strategies that included actions targeting multiple threats and demographic rates resulted in the highest persistence probability, and roadside barriers, which increased adult survival, were predicted to increase persistence more than other actions. Our results support earlier findings showing mitigation of multiple threats is likely required to increase the viability of declining populations. Our approach illustrates how integrated models may be adapted to use limited data efficiently, represent system complexity, evaluate impacts of threats and management actions, and provide decision-relevant information for conservation of at-risk populations.

@article{cecala_multiple_2018,
	title = {Multiple drivers, scales, and interactions influence southern {Appalachian} stream salamander occupancy},
	volume = {9},
	copyright = {All rights reserved},
	doi = {10.1002/ecs2.2150},
	abstract = {Understanding how factors that vary in spatial scale relate to population abundance is vital to forecasting species responses to environmental change. Stream and river ecosystems are inherently hierar- chical, potentially resulting in organismal responses to fine-scale changes in patch characteristics that are conditional on the watershed context. Here, we address how populations of two salamander species are affected by interactions among hierarchical processes operating at different scales within a rapidly chang- ing landscape of the southern Appalachian Mountains. We modeled reach-level occupancy of larval and adult black-bellied salamanders (Desmognathus quadramaculatus) and larval Blue Ridge two-lined salaman- ders (Eurycea wilderae) as a function of 17 different terrestrial and aquatic predictor variables that varied in spatial extent. We found that salamander occurrence varied widely among streams within fully forested catchments, but also exhibited species-specific responses to changes in local conditions. While D. quadra- maculatus declined predictably in relation to losses in forest cover, larval occupancy exhibited the strongest negative response to forest loss as well as decreases in elevation. Conversely, occupancy of E. wilderae was unassociated with watershed conditions, only responding negatively to higher proportions of fast-flowing stream habitat types. Evaluation of hierarchical relationships demonstrated that most fine-scale variables were closely correlated with broad watershed-scale variables, suggesting that local reach-scale factors have relatively smaller effects within the context of the larger landscape. Our results imply that effective man- agement of southern Appalachian stream salamanders must first focus on the larger scale condition of watersheds before management of local-scale conditions should proceed. Our findings confirm the results of some studies while refuting the results of others, which may indicate that prescriptive recommendations for range-wide management of species or the application of a single management focus across large geo- graphic areas is inappropriate.},
	number = {3},
	journal = {Ecosphere},
	author = {Cecala, Kristen K and Maerz, John C and Halstead, Brian J and Frisch, John R and Gragson, Ted L and Hepinstall-Cymerman, Jeffrey and Leigh, David and Jackson, C Rhett and Peterson, James T and Pringle, Catherine M},
	year = {2018},
	keywords = {Appalachian Mountains, Blue Ridge, Desmognathus quadramaculatus, Eurycea wilderae, distribution, land- use change, occupancy, riparian, salamander, scale},
	pages = {e02150.--e02150.},
}

Understanding how factors that vary in spatial scale relate to population abundance is vital to forecasting species responses to environmental change. Stream and river ecosystems are inherently hierar- chical, potentially resulting in organismal responses to fine-scale changes in patch characteristics that are conditional on the watershed context. Here, we address how populations of two salamander species are affected by interactions among hierarchical processes operating at different scales within a rapidly chang- ing landscape of the southern Appalachian Mountains. We modeled reach-level occupancy of larval and adult black-bellied salamanders (Desmognathus quadramaculatus) and larval Blue Ridge two-lined salaman- ders (Eurycea wilderae) as a function of 17 different terrestrial and aquatic predictor variables that varied in spatial extent. We found that salamander occurrence varied widely among streams within fully forested catchments, but also exhibited species-specific responses to changes in local conditions. While D. quadra- maculatus declined predictably in relation to losses in forest cover, larval occupancy exhibited the strongest negative response to forest loss as well as decreases in elevation. Conversely, occupancy of E. wilderae was unassociated with watershed conditions, only responding negatively to higher proportions of fast-flowing stream habitat types. Evaluation of hierarchical relationships demonstrated that most fine-scale variables were closely correlated with broad watershed-scale variables, suggesting that local reach-scale factors have relatively smaller effects within the context of the larger landscape. Our results imply that effective man- agement of southern Appalachian stream salamanders must first focus on the larger scale condition of watersheds before management of local-scale conditions should proceed. Our findings confirm the results of some studies while refuting the results of others, which may indicate that prescriptive recommendations for range-wide management of species or the application of a single management focus across large geo- graphic areas is inappropriate.

@article{demi_litter_2018,
	title = {Litter {P} content drives consumer production in detritus-based streams spanning an experimental {N}:{P} gradient},
	volume = {99},
	copyright = {All rights reserved},
	issn = {0012-9658},
	doi = {10.1002/ecy.2118},
	abstract = {Ecological stoichiometry theory (EST) is a key framework for predicting how variation in N:P supply ratios influences biological processes, at molecular to ecosystem scales, by altering the availability of C, N, and P relative to organismal requirements. We tested EST predictions by fertilizing five forest streams at different dissolved molar N:P ratios (2, 8, 16, 32, 128) for two years and tracking responses of macroinvertebrate consumers to the resulting steep experimental gradient in basal resource stoichiometry (leaf litter \%N, \%P, and N:P). Nitrogen and P content of leaf litter, the dominant basal resource, increased in all five streams following enrichment, with steepest responses in litter \%P and N:P ratio. Additionally, increases in primary consumer biomass and production occurred in all five streams following N and P enrichment (averages across all streams: biomass by 1.2×, production by 1.6×). Patterns of both biomass and production were best predicted by leaf litter N:P and \%P and were unrelated to leaf litter \%N. Primary consumer production increased most in streams where decreases in leaf litter N:P were largest. Macroinvertebrate predator biomass and production were also strongly positively related to litter \%P, providing robust experimental evidence for the primacy of P limitation at multiple trophic levels in these ecosystems. However, production of predatory macroinvertebrates was not related directly to primary consumer production, suggesting the importance of additional controls for macroinvertebrates at upper trophic positions. Our results reveal potential drivers of animal production in detritus-based ecosystems, including the relative importance of resource quality vs. quantity. Our study also sheds light on the more general impacts of variation in N:P supply ratio on nutrient-poor ecosystems, providing strong empirical support for predictions that nutrient enrichment increases food web productivity whenever large elemental imbalances between basal resources and consumer demand are reduced.},
	number = {2},
	journal = {Ecology},
	author = {Demi, Lee M. and Benstead, Jonathan P. and Rosemond, Amy D. and Maerz, John C.},
	year = {2018},
	keywords = {carbon, detritus, ecological stoichiometry, nitrogen, nutrient enrichment, phosphorus, rivers, secondary production, streams},
	pages = {347--359},
}

Ecological stoichiometry theory (EST) is a key framework for predicting how variation in N:P supply ratios influences biological processes, at molecular to ecosystem scales, by altering the availability of C, N, and P relative to organismal requirements. We tested EST predictions by fertilizing five forest streams at different dissolved molar N:P ratios (2, 8, 16, 32, 128) for two years and tracking responses of macroinvertebrate consumers to the resulting steep experimental gradient in basal resource stoichiometry (leaf litter %N, %P, and N:P). Nitrogen and P content of leaf litter, the dominant basal resource, increased in all five streams following enrichment, with steepest responses in litter %P and N:P ratio. Additionally, increases in primary consumer biomass and production occurred in all five streams following N and P enrichment (averages across all streams: biomass by 1.2×, production by 1.6×). Patterns of both biomass and production were best predicted by leaf litter N:P and %P and were unrelated to leaf litter %N. Primary consumer production increased most in streams where decreases in leaf litter N:P were largest. Macroinvertebrate predator biomass and production were also strongly positively related to litter %P, providing robust experimental evidence for the primacy of P limitation at multiple trophic levels in these ecosystems. However, production of predatory macroinvertebrates was not related directly to primary consumer production, suggesting the importance of additional controls for macroinvertebrates at upper trophic positions. Our results reveal potential drivers of animal production in detritus-based ecosystems, including the relative importance of resource quality vs. quantity. Our study also sheds light on the more general impacts of variation in N:P supply ratio on nutrient-poor ecosystems, providing strong empirical support for predictions that nutrient enrichment increases food web productivity whenever large elemental imbalances between basal resources and consumer demand are reduced.

@article{bumpers_experimental_2017,
	title = {Experimental nutrient enrichment of forest streams increases energy flow to predators along greener food-web pathways},
	volume = {62},
	copyright = {All rights reserved},
	doi = {10.1111/fwb.12992},
	abstract = {1. Nutrient enrichment is a key stressor of lakes and streams globally, affecting the relative availability of important basal resources such as algae and detritus. These effects are controlled by responses of autotrophic and heterotrophic microorganisms that subsequently affect primary consumers and higher level predators. Despite the potential for propagation of these bottom-up effects, few studies have examined how nutrients affect “green” (autotrophic) versus “brown” (heterotrophic) energy pathways to predators via changes in the quantity or type of prey consumed. 

2. We studied the pathways by which nutrient enrichment affected two predatory salamander species (Desmognathus quadramaculatus and Eurycea wilderae) using detailed diet analyses before and during 2-year nutrient additions to five headwater forest streams. The streams were continuously enriched with different concentrations of dissolved nitrogen (N) and phosphorus (P), creating relatively greater N or P concentrations and distinct N:P ratios (2:1, 8:1, 16:1, 32:1 and 128:1) in each stream. 

3. Nutrient addition resulted in greater prey number, size and biomass consumed by D. quadramaculatus, an effect driven more by P than by N additions. Some of these effects were greater in the second year of enrichment and were greater for larger individuals. Shifts in the prey composition of D. quadramaculatus included increases in algivores and decreases in detritivores, tracking observed treatment effects on basal resource quantity (e.g. algivore abundance in guts was related to algal biomass, which increased with enrichment, and detritivore abundance in guts was related to detrital standing stocks, which declined with enrichment). For E. wilderae diets, there was limited evidence for increased prey size and number, or for alteration of prey composition with enrichment despite evidence of increased larval growth. We hypothesise that body size differences between the two salamander species partially explain their different dietary responses to enrichment. 

4. Our results show that nutrient addition, primarily of P, affected the quantity and composition of predator diets in our nutrient-poor streams. These effects on diet were consistent with concurrent studies showing that P enrichment resulted in faster growth of salamanders and occurred partly via effects on algal biofilm or “green” food-web pathways, despite the dominance of detrital or “brown” resources in our heavily shaded forest stream sites. Thus, nutrient enrichment},
	number = {10},
	journal = {Freshwater Biology},
	author = {Bumpers, P.M. and Rosemond, A.D. and Maerz, J.C. and Benstead, J.P.},
	year = {2017},
	keywords = {Desmognathus quadramaculatus, Eurycea wilderae, food webs, nutrients, salamanders},
	pages = {1794--1805},
}

1. Nutrient enrichment is a key stressor of lakes and streams globally, affecting the relative availability of important basal resources such as algae and detritus. These effects are controlled by responses of autotrophic and heterotrophic microorganisms that subsequently affect primary consumers and higher level predators. Despite the potential for propagation of these bottom-up effects, few studies have examined how nutrients affect “green” (autotrophic) versus “brown” (heterotrophic) energy pathways to predators via changes in the quantity or type of prey consumed. 2. We studied the pathways by which nutrient enrichment affected two predatory salamander species (Desmognathus quadramaculatus and Eurycea wilderae) using detailed diet analyses before and during 2-year nutrient additions to five headwater forest streams. The streams were continuously enriched with different concentrations of dissolved nitrogen (N) and phosphorus (P), creating relatively greater N or P concentrations and distinct N:P ratios (2:1, 8:1, 16:1, 32:1 and 128:1) in each stream. 3. Nutrient addition resulted in greater prey number, size and biomass consumed by D. quadramaculatus, an effect driven more by P than by N additions. Some of these effects were greater in the second year of enrichment and were greater for larger individuals. Shifts in the prey composition of D. quadramaculatus included increases in algivores and decreases in detritivores, tracking observed treatment effects on basal resource quantity (e.g. algivore abundance in guts was related to algal biomass, which increased with enrichment, and detritivore abundance in guts was related to detrital standing stocks, which declined with enrichment). For E. wilderae diets, there was limited evidence for increased prey size and number, or for alteration of prey composition with enrichment despite evidence of increased larval growth. We hypothesise that body size differences between the two salamander species partially explain their different dietary responses to enrichment. 4. Our results show that nutrient addition, primarily of P, affected the quantity and composition of predator diets in our nutrient-poor streams. These effects on diet were consistent with concurrent studies showing that P enrichment resulted in faster growth of salamanders and occurred partly via effects on algal biofilm or “green” food-web pathways, despite the dominance of detrital or “brown” resources in our heavily shaded forest stream sites. Thus, nutrient enrichment

@article{crawford_mitigating_2017,
	title = {Mitigating road mortality of {Diamond}-backed {Terrapins} ({Malaclemys} terrapin) with hybrid barriers at crossing hot spots},
	volume = {12},
	copyright = {All rights reserved},
	abstract = {Roads represent a pervasive feature on most landscapes that can pose multiple threats to wildlife populations and substantial challenges for management. To be effective, management strategies must often target where threats are most concentrated. Road mortality and nest predation are well-documented threats to Diamondbacked Terrapins (Malaclemys terrapin) across the majority of their range, including the 8.7-km causeway to Jekyll Island, Georgia, USA, where both are predicted to contribute to population declines if left unmitigated. From 2009 to 2014, we used intensive road surveying to identify spatial peaks (hot spots) of terrapin crossing activity and road mortality and exploit these as targets for management. In 2011, we deployed a hybrid barrier composed of nest boxes, which were designed to prevent terrapins from accessing the road and mitigate nest predation, at one hot spot while leaving two other hot spots unmanaged. We evaluated the impact of the barrier on terrapin emergences on the causeway under a Before-After-Control-Impact (BACI) design, and a companion study evaluated the effects of nest boxes on nest predation rates. We estimated a 57\% reduction in annual terrapin emergences at the barrier site compared to no measurable change at control hot spots. Our findings support the use of hybrid barriers for simultaneously addressing road mortality and nest predation for other terrapin populations at risk to these threats. Our approach highlights the need to design feasible but robust management strategies that target spatial peaks of road mortality while addressing additional threats contributing to population declines of terrapins and other species.},
	number = {1},
	journal = {Herpetological Conservation and Biology},
	author = {Crawford, B.A. and Moore, C.T. and Norton, T.M. and Maerz, J.C.},
	year = {2017},
	keywords = {Before-After-Control-Impact (BACI), Conservation management, Nest predation, Turtle, Wildlife-vehicle collision},
	pages = {202--211},
}

Roads represent a pervasive feature on most landscapes that can pose multiple threats to wildlife populations and substantial challenges for management. To be effective, management strategies must often target where threats are most concentrated. Road mortality and nest predation are well-documented threats to Diamondbacked Terrapins (Malaclemys terrapin) across the majority of their range, including the 8.7-km causeway to Jekyll Island, Georgia, USA, where both are predicted to contribute to population declines if left unmitigated. From 2009 to 2014, we used intensive road surveying to identify spatial peaks (hot spots) of terrapin crossing activity and road mortality and exploit these as targets for management. In 2011, we deployed a hybrid barrier composed of nest boxes, which were designed to prevent terrapins from accessing the road and mitigate nest predation, at one hot spot while leaving two other hot spots unmanaged. We evaluated the impact of the barrier on terrapin emergences on the causeway under a Before-After-Control-Impact (BACI) design, and a companion study evaluated the effects of nest boxes on nest predation rates. We estimated a 57% reduction in annual terrapin emergences at the barrier site compared to no measurable change at control hot spots. Our findings support the use of hybrid barriers for simultaneously addressing road mortality and nest predation for other terrapin populations at risk to these threats. Our approach highlights the need to design feasible but robust management strategies that target spatial peaks of road mortality while addressing additional threats contributing to population declines of terrapins and other species.

@article{fouts_lizard_2017,
	title = {Lizard activity and abundance greater in burned habitat of a xeric montane forest},
	volume = {8},
	copyright = {All rights reserved},
	doi = {10.3996/042016-JFWM-031},
	abstract = {Restoring the natural or historical state of ecosystems is a common objective among resource managers, but determining whether desired system responses to management actions are occurring is often protracted and challenging. For wildlife, the integration of mechanistic habitat modeling with population monitoring may provide expedited measures of management effectiveness and improve understanding of how management actions succeed or fail to recover populations. Southern Appalachia is a region of high biodiversity that has undergone dramatic change as a result of human activities such as historic logging, exotic invasions, and alteration of disturbance regimes—including reduction in application of fire. Contemporary efforts to restore fire-maintained ecosystems within southern Appalachian forests require tools to assess the effects of fire management practices on individual animal fitness and relate them to corresponding influences on species abundance. Using automated sensing equipment, we investigated the effects of burned forests on reptile habitat suitability within the western portion of Great Smoky Mountains National Park, Tennessee. Specifically, we used microclimate measurements to model northern fence lizard Sceloporus undulatus hyacinthinus diurnal activity budgets in unburned and variable burn age (327-y) forest stands. We estimated northern fence lizard occurrence and abundance along transects through burned and unburned forests. Burned forest stands had microclimates that resulted in longer modeled daily activity periods under most conditions during summer. S. undulatus abundance was 4.75 times greater on burned stands compared to paired unburned stands, although the relationship between burn age and abundance was not well determined. Results suggest the more open habitat structure of burned areas within these xeric pine–oak forests may benefit S. undulatus.},
	number = {1},
	journal = {Journal of Fish and Wildlife Management},
	author = {Fouts, K.L. and Moore, C.T. and Johnson, K.D. and Maerz, J.C.},
	year = {2017},
	keywords = {Bayesian abundance estimation, Fire management, Operative temperature and activity modeling, Sceloporus, Southern Appalachians},
	pages = {181--192},
}

Restoring the natural or historical state of ecosystems is a common objective among resource managers, but determining whether desired system responses to management actions are occurring is often protracted and challenging. For wildlife, the integration of mechanistic habitat modeling with population monitoring may provide expedited measures of management effectiveness and improve understanding of how management actions succeed or fail to recover populations. Southern Appalachia is a region of high biodiversity that has undergone dramatic change as a result of human activities such as historic logging, exotic invasions, and alteration of disturbance regimes—including reduction in application of fire. Contemporary efforts to restore fire-maintained ecosystems within southern Appalachian forests require tools to assess the effects of fire management practices on individual animal fitness and relate them to corresponding influences on species abundance. Using automated sensing equipment, we investigated the effects of burned forests on reptile habitat suitability within the western portion of Great Smoky Mountains National Park, Tennessee. Specifically, we used microclimate measurements to model northern fence lizard Sceloporus undulatus hyacinthinus diurnal activity budgets in unburned and variable burn age (327-y) forest stands. We estimated northern fence lizard occurrence and abundance along transects through burned and unburned forests. Burned forest stands had microclimates that resulted in longer modeled daily activity periods under most conditions during summer. S. undulatus abundance was 4.75 times greater on burned stands compared to paired unburned stands, although the relationship between burn age and abundance was not well determined. Results suggest the more open habitat structure of burned areas within these xeric pine–oak forests may benefit S. undulatus.

@article{vanni_global_2017,
	title = {A global database of nitrogen and phosphorus excretion rates of aquatic animals},
	volume = {98},
	copyright = {All rights reserved},
	doi = {10.1002/ecy.1792},
	abstract = {Animals can be important in modulating ecosystem-level nutrient cycling, although their importance varies greatly among species and ecosystems. Nutrient cycling rates of individual animals represent valuable data for testing the predictions of important frameworks such as the Metabolic Theory of Ecology (MTE) and ecological stoichiometry (ES). They also represent an important set of functional traits that may reflect both environmental and phylogenetic influences. Over the past two decades, studies of animal-mediated nutrient cycling have increased dramatically, especially in aquatic ecosystems. Here we present a global compilation of aquatic animal nutrient excretion rates. The dataset includes 10,534 observations from freshwater and marine animals of N and/or P excretion rates. These observations represent 491 species, including most aquatic phyla. Coverage varies greatly among phyla and other taxonomic levels. The dataset includes information on animal body size, ambient temperature, taxonomic affiliations, and animal body N:P. This data set was used to test predictions of MTE and ES, as described in Vanni and McIntyre (2016; Ecology DOI: 10.1002/ecy.1582).},
	number = {5},
	journal = {Ecology},
	author = {Vanni, M.J. and McIntyre, P.B. and Allen, D. and Arnott, D.L. and Benstead, J.P. and Berg, D.J. and Brabrand, Å. and Brosse, S. and Bukaveckas, P.A. and Caliman, A. and Capps, K.A. and Carneiro, L.S. and Chadwick, N.E. and Christian, A.D. and Clarke, A. and Conroy, J.D. and Cross, W.F. and Culver, D.A. and Dalton, C.M. and Devine, J.A. and Domine, L.M. and Evans-White, M.A. and Faafeng, B.A. and Flecker, A.S. and Gido, K.B. and Godinot, C. and Guariento, R.D. and Haertel-Borer, S. and Hall, R.O. and Henry, R. and Herwig, B.R. and Hicks, B.J. and Higgins, K.A. and Hood, J.M. and Hopton, M.E. and Ikeda, T. and James, W.F. and Jansen, H.M. and Johnson, C.R. and Koch, B.J. and Lamberti, G.A. and Lessard-Pilon, S. and Maerz, J.C. and Mather, M.E. and McManamay, R.A. and Milanovich, J.R. and Morgan, D.K.J. and Moslemi, J.M. and Naddafi, R. and Nilssen, J.P. and Pagano, M. and Pilati, A. and Post, D.M. and Roopin, M. and Rugenski, A.T. and Schaus, M.H. and Shostell, J. and Small, G.E. and Solomon, C.T. and Sterrett, S.C. and Strand, Ø. and Tarvainen, M. and Taylor, J.M. and Torres-Gerald, L.E. and Turner, C.B. and Urabe, J. and Uye, S.-I. and Ventelä, A.-M. and Villeger, S. and Whiles, M.R. and Wilhelm, F.M. and Wilson, H.F. and Xenopoulos, M.A. and Zimmer, K.D.},
	year = {2017},
	keywords = {body size, ecological stoichiometry, freshwater and marine ecosystems (lakes, invertebrates, metabolic ecology, nitrogen excretion, nutrient cycling, phosphorus excretion, rivers an, temperature, vertebrates},
}

Animals can be important in modulating ecosystem-level nutrient cycling, although their importance varies greatly among species and ecosystems. Nutrient cycling rates of individual animals represent valuable data for testing the predictions of important frameworks such as the Metabolic Theory of Ecology (MTE) and ecological stoichiometry (ES). They also represent an important set of functional traits that may reflect both environmental and phylogenetic influences. Over the past two decades, studies of animal-mediated nutrient cycling have increased dramatically, especially in aquatic ecosystems. Here we present a global compilation of aquatic animal nutrient excretion rates. The dataset includes 10,534 observations from freshwater and marine animals of N and/or P excretion rates. These observations represent 491 species, including most aquatic phyla. Coverage varies greatly among phyla and other taxonomic levels. The dataset includes information on animal body size, ambient temperature, taxonomic affiliations, and animal body N:P. This data set was used to test predictions of MTE and ES, as described in Vanni and McIntyre (2016; Ecology DOI: 10.1002/ecy.1582).

@article{mckee_habitat_2017,
	title = {Habitat predictors of genetic diversity for two sympatric wetland-breeding amphibian species},
	volume = {7},
	copyright = {All rights reserved},
	doi = {10.1002/ece3.3203},
	abstract = {Population genetic diversity is widely accepted as important to the conservation and management of wildlife. However, habitat features may differentially affect evolutionary processes that facilitate population genetic diversity among sympatric species. We measured genetic diversity for two pond-breeding amphibian species (Dwarf salamanders, Eurycea quadridigitata; and Southern Leopard frogs, Lithobates sphenocephalus) to understand how habitat characteristics and spatial scale affect genetic diversity across a landscape. Samples were collected from wetlands on a longleaf pine reserve in Georgia. We genotyped microsatellite loci for both species to assess population structures and determine which habitat features were most closely associated with observed heterozygosity and rarefied allelic richness. Both species exhibited significant population genetic structure; however, structure in Southern Leopard frogs was driven primarily by one outlier site. Dwarf salamander allelic richness was greater at sites with less surrounding road area within 0.5 km and more wetland area within 1.0 and 2.5 km, and heterozygosity was greater at sites with more wetland area within 0.5 km. In contrast, neither measure of Southern Leopard frog genetic diversity was associated with any habitat features at any scale we evaluated. Genetic diversity in the Dwarf salamander was strongly associated with land cover variables up to 2.5 km away from breeding wetlands, and/or results suggest that minimizing roads in wetland buffers may be beneficial to the maintenance of population genetic diversity. This study suggests that patterns of genetic differentiation and genetic diversity have associations with different habitat features across different spatial scales for two syntopic pond-breeding amphibian species.},
	number = {16},
	journal = {Ecology and Evolution},
	author = {McKee, A.M. and Maerz, J.C. and Smith, L.L. and Glenn, T.C.},
	year = {2017},
	keywords = {Eurycea, Lithobates (Rana), allelic richness, heterozygosity, isolated wetlands, landscape genetics, longleaf pine, microsatellite},
	pages = {1--13},
}

Population genetic diversity is widely accepted as important to the conservation and management of wildlife. However, habitat features may differentially affect evolutionary processes that facilitate population genetic diversity among sympatric species. We measured genetic diversity for two pond-breeding amphibian species (Dwarf salamanders, Eurycea quadridigitata; and Southern Leopard frogs, Lithobates sphenocephalus) to understand how habitat characteristics and spatial scale affect genetic diversity across a landscape. Samples were collected from wetlands on a longleaf pine reserve in Georgia. We genotyped microsatellite loci for both species to assess population structures and determine which habitat features were most closely associated with observed heterozygosity and rarefied allelic richness. Both species exhibited significant population genetic structure; however, structure in Southern Leopard frogs was driven primarily by one outlier site. Dwarf salamander allelic richness was greater at sites with less surrounding road area within 0.5 km and more wetland area within 1.0 and 2.5 km, and heterozygosity was greater at sites with more wetland area within 0.5 km. In contrast, neither measure of Southern Leopard frog genetic diversity was associated with any habitat features at any scale we evaluated. Genetic diversity in the Dwarf salamander was strongly associated with land cover variables up to 2.5 km away from breeding wetlands, and/or results suggest that minimizing roads in wetland buffers may be beneficial to the maintenance of population genetic diversity. This study suggests that patterns of genetic differentiation and genetic diversity have associations with different habitat features across different spatial scales for two syntopic pond-breeding amphibian species.

@article{cohen_color_2016,
	title = {Color perception influences microhabitat selection of refugia and affects monitoring success for a cryptic anuran species},
	volume = {164},
	copyright = {All rights reserved},
	doi = {10.1016/j.physbeh.2016.05.042},
	abstract = {Perceptual-biases are important for understanding an animal's natural history, identifying potential ecological traps, and for developing effective means to monitor individuals and populations. Despite research demonstrating anurans having a positive phototactic response towards blue colors, we do not yet understand if color cues are used functionally beyond sexual selection. The aim of our study was to determine if color cues are used in selecting microhabitat, and if anuran's blue-positive phototactic response could increase selection of artificial PVC refugia used to monitor cryptic camouflaging anuran species. We captured 32 Cope's Gray Treefrogs and placed them in mesh enclosures with three PVC tubes painted blue, brown, and white. Concurrently, we placed blue, brown, or unpainted white PVC tubes in stratified arrays around a treefrog breeding pond, and counted the number of occasions treefrogs occupied different colored PVC tubes. In the confined choice experiment, treefrogs selected blue tubes (48.3\%) significantly more often than brown (28.5\%) or white (23.2\%) tubes. Our field experiment mirrored these findings (52.0\% of capture events in blue, 29.0\% in brown, and 19.0\% in unpainted white tubes). Our results suggest color influences Cope's Gray Treefrog microhabitat selection, and they utilize color vision when choosing refugia. We demonstrate simple, small changes based on perceptual-biases can induce behaviors that may in turn have large impacts on sampling techniques used in monitoring and inventorying. Incorporating non-traditional physiological measures into animal inventorying and monitoring programs can be used in the future to improve conservation efforts.},
	journal = {Physiology and Behavior},
	author = {Cohen, B.S. and MacKenzie, M.L. and Maerz, J.C. and Farrell, C.B. and Castleberry, S.B.},
	year = {2016},
	keywords = {Detection, Hyla chrysoscelis, Micro, [Color vision},
	pages = {54--57},
}

Perceptual-biases are important for understanding an animal's natural history, identifying potential ecological traps, and for developing effective means to monitor individuals and populations. Despite research demonstrating anurans having a positive phototactic response towards blue colors, we do not yet understand if color cues are used functionally beyond sexual selection. The aim of our study was to determine if color cues are used in selecting microhabitat, and if anuran's blue-positive phototactic response could increase selection of artificial PVC refugia used to monitor cryptic camouflaging anuran species. We captured 32 Cope's Gray Treefrogs and placed them in mesh enclosures with three PVC tubes painted blue, brown, and white. Concurrently, we placed blue, brown, or unpainted white PVC tubes in stratified arrays around a treefrog breeding pond, and counted the number of occasions treefrogs occupied different colored PVC tubes. In the confined choice experiment, treefrogs selected blue tubes (48.3%) significantly more often than brown (28.5%) or white (23.2%) tubes. Our field experiment mirrored these findings (52.0% of capture events in blue, 29.0% in brown, and 19.0% in unpainted white tubes). Our results suggest color influences Cope's Gray Treefrog microhabitat selection, and they utilize color vision when choosing refugia. We demonstrate simple, small changes based on perceptual-biases can induce behaviors that may in turn have large impacts on sampling techniques used in monitoring and inventorying. Incorporating non-traditional physiological measures into animal inventorying and monitoring programs can be used in the future to improve conservation efforts.

@article{craven_unseen_2016,
	title = {The unseen invaders: introduced earthworms as drivers of change in plant communities in {North} {American} forests (a meta-analysis)},
	volume = {2016},
	copyright = {All rights reserved},
	issn = {1365-2486 (Electronic) 1354-1013 (Linking)},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/27590777},
	doi = {10.1111/gcb.13446},
	abstract = {Globally, biological invasions can have strong impacts on biodiversity as well as ecosystem functioning. While less conspicuous than introduced aboveground organisms, introduced belowground organisms may have similarly strong effects. Here, we synthesize for the first time the impacts of introduced earthworms on plant diversity and community composition in North American forests. We conducted a meta-analysis using a total of 645 observations to quantify mean effect sizes of associations between introduced earthworm communities and plant diversity, cover of plant functional groups, and cover of native and non-native plants. We found that plant diversity significantly declined with increasing richness of introduced earthworm ecological groups. While plant species richness or evenness did not change with earthworm invasion, our results indicate clear changes in plant community composition: cover of graminoids and non-native plant species significantly increased, and cover of native plant species (of all functional groups) tended to decrease, with increasing earthworm biomass. Overall, these findings support the hypothesis that introduced earthworms facilitate particular plant species adapted to the abiotic conditions of earthworm-invaded forests. Further, our study provides evidence that introduced earthworms are associated with declines in plant diversity in North American forests. Changing plant functional composition in these forests may have long-lasting effects on ecosystem functioning.},
	journal = {Glob Chang Biol},
	author = {Craven, D. and Thakur, M. P. and Cameron, E. K. and Frelich, Lee E. and Beausejour, R. and Blair, R. B. and Blossey, Bernd and Burtis, J. and Choi, A. and Davalos, Andrea and Fahey, Timothy J. and Fisichelli, N. A. and Gibson, K. and Handa, I. T. and Hopfensperger, K. and Loss, Scott R. and Nuzzo, Victoria and Maerz, John C. and Sackett, T. and Scharenbroch, B. C. and Smith, S. M. and Vellend, Mark and Umek, L. G. and Eisenhauer, N.},
	year = {2016},
	keywords = {biological invasions, community composition, earthworm invasion, introduced earthworms, meta-analysis, plant communities, plant diversity},
	pages = {1--10},
}

Globally, biological invasions can have strong impacts on biodiversity as well as ecosystem functioning. While less conspicuous than introduced aboveground organisms, introduced belowground organisms may have similarly strong effects. Here, we synthesize for the first time the impacts of introduced earthworms on plant diversity and community composition in North American forests. We conducted a meta-analysis using a total of 645 observations to quantify mean effect sizes of associations between introduced earthworm communities and plant diversity, cover of plant functional groups, and cover of native and non-native plants. We found that plant diversity significantly declined with increasing richness of introduced earthworm ecological groups. While plant species richness or evenness did not change with earthworm invasion, our results indicate clear changes in plant community composition: cover of graminoids and non-native plant species significantly increased, and cover of native plant species (of all functional groups) tended to decrease, with increasing earthworm biomass. Overall, these findings support the hypothesis that introduced earthworms facilitate particular plant species adapted to the abiotic conditions of earthworm-invaded forests. Further, our study provides evidence that introduced earthworms are associated with declines in plant diversity in North American forests. Changing plant functional composition in these forests may have long-lasting effects on ecosystem functioning.

@article{eberhard_possible_2016,
	title = {Possible role of fish and frogs as paratenic hosts of {Dracunculus} medinensis, {Chad}},
	volume = {22},
	copyright = {All rights reserved},
	doi = {10.3201/eid2208.160043},
	abstract = {Copepods	infected with Dracunculus medinensis larvae collected	from	infected dogs in Chad were fed to 2 species of fish and tadpoles. Although they	readily ingested copepods, neither species of fish, Nile tilapia (Oreochromis niloticus) nor fathead minnow (Pimephalis promelas), were found to harbor Dracunculus larvae when examined 2–3	weeks later. Tadpoles ingested copepods much more slowly; however, upon examination at the same time	interval, tadpoles of green frogs (Lithobates [Rana] clamitans)	were	found to harbor small numbers of Dracunculus larvae. Two ferrets (Mustela putorius furo) were fed fish	or tadpoles that had been exposed to infected	copepods.	 Only	the ferret fed tadpoles harbored developing Dracunculus larvae at necropsy 70–80 days postexposure. These observations confirm that D. medinensis, like other species in the genus Dracunculus, can readily survive and remain infective in potential paratenic hosts, especially tadpoles.},
	number = {8},
	journal = {Emerging Infectious Diseases},
	author = {Eberhard, M.L. and Yabsley, M.J. and Zirimwabagabo, H. and Bishop, H. and Cleveland, C.A. and Maerz, J.C. and Bringolf, R. and Ruiz-Tiben, E.},
	year = {2016},
	pages = {1428--1430},
}

Copepods infected with Dracunculus medinensis larvae collected from infected dogs in Chad were fed to 2 species of fish and tadpoles. Although they readily ingested copepods, neither species of fish, Nile tilapia (Oreochromis niloticus) nor fathead minnow (Pimephalis promelas), were found to harbor Dracunculus larvae when examined 2–3 weeks later. Tadpoles ingested copepods much more slowly; however, upon examination at the same time interval, tadpoles of green frogs (Lithobates [Rana] clamitans) were found to harbor small numbers of Dracunculus larvae. Two ferrets (Mustela putorius furo) were fed fish or tadpoles that had been exposed to infected copepods. Only the ferret fed tadpoles harbored developing Dracunculus larvae at necropsy 70–80 days postexposure. These observations confirm that D. medinensis, like other species in the genus Dracunculus, can readily survive and remain infective in potential paratenic hosts, especially tadpoles.

@article{frisch_patch_2016,
	title = {Patch occupancy of stream fauna across a land cover gradient in the southern {Appalachians}, {USA}},
	volume = {773},
	copyright = {All rights reserved},
	doi = {10.1007/s10750-016-2695-9},
	abstract = {We modeled patch occupancy to examine factors that best predicted the prevalence of four functionally important focal stream consumers (Tallaperla spp., Cambarus spp., Pleurocera proxima, and Cottus bairdi) among 37 reaches within the Little Tennessee River basin of the southern Appalachian Mountains, USA. We compared 34 models of patch occupancy to examine the association of catchment and reach scale factors that varied as a result of converting forest to agricultural or urban land use. Occupancy of our taxa was linked to parameters reflecting both catchment and reach extent characteristics. At the catchment level, forest cover or its conversion to agriculture was a major determinant of occupancy for all four taxa. Patch occupancies of Tallaperla, Cambarus, and C. bairdi were positively, and Pleurocera negatively, correlated with forest cover. Secondarily at the reach level, local availability of large woody debris was important for Cambarus, availability of large cobble substrate was important for C. bairdi, and stream calcium concentration was important for P. proxima. Our results show the abundance of stream organisms was determined by the taxon-dependent interplay between catchmentand reach-level factors.},
	number = {1},
	journal = {Hydrobiologia},
	author = {Frisch, J.R. and Peterson, J.T. and Cecala, K.K. and Maerz, J.C. and Jackson, C.R. and Gragson, T.L. and Pringle, C.M.},
	year = {2016},
	keywords = {Consumers, Land use, Patch occupanc, [Appalachians},
	pages = {163--175},
}

We modeled patch occupancy to examine factors that best predicted the prevalence of four functionally important focal stream consumers (Tallaperla spp., Cambarus spp., Pleurocera proxima, and Cottus bairdi) among 37 reaches within the Little Tennessee River basin of the southern Appalachian Mountains, USA. We compared 34 models of patch occupancy to examine the association of catchment and reach scale factors that varied as a result of converting forest to agricultural or urban land use. Occupancy of our taxa was linked to parameters reflecting both catchment and reach extent characteristics. At the catchment level, forest cover or its conversion to agriculture was a major determinant of occupancy for all four taxa. Patch occupancies of Tallaperla, Cambarus, and C. bairdi were positively, and Pleurocera negatively, correlated with forest cover. Secondarily at the reach level, local availability of large woody debris was important for Cambarus, availability of large cobble substrate was important for C. bairdi, and stream calcium concentration was important for P. proxima. Our results show the abundance of stream organisms was determined by the taxon-dependent interplay between catchmentand reach-level factors.

@article{manning_convergence_2016,
	title = {Convergence of detrital stoichiometry predicts thresholds of nutrient-stimulated breakdown in streams},
	volume = {26},
	copyright = {All rights reserved},
	doi = {10.1890/15-1217.1},
	abstract = {Nutrient enrichment of detritus-based streams increases detrital resource quality for consumers and stimulates breakdown rates of particulate organic carbon (C). The relative importance of dissolved inorganic nitrogen (N) vs. phosphorus (P) for detrital quality and their effects on microbial- vs. detritivore-mediated detrital breakdown are poorly understood. We tested effects of experimental N and P additions on detrital stoichiometry (C:N, C:P) and total and microbial breakdown (i.e., with and without detritivorous shredders, respectively) of five detritus types (four leaf litter species and wood) with different initial C: nutrient content. We enriched five headwater streams continuously for two years at different relative availabilities of N and P and compared breakdown rates and detrital stoichiometry to pretreatment conditions. Total breakdown rates increased with nutrient enrichment and were predicted by altered detrital stoichiometry. Streamwater N and P, fungal biomass, and their interactions affected stoichiometry of detritus. Streamwater N and P decreased detrital C:N, whereas streamwater P had stronger negative effects on detrital C:P. Nutrient addition and fungal biomass reduced C:N by 70\% and C:P by 83\% on average after conditioning, compared to only 26\% for C:N and 10\% for C:P under pretreatment conditions. Detritus with lowest initial nutrient content changed the most and had greatest increases in total breakdown rates. Detrital stoichiometry was reduced and differences among detritus types were homogenized by nutrient enrichment. With enrichment, detrital nutrient content approached detritivore nutritional requirements and stimulated greater detritivore vs. microbial litter breakdown. We used breakpoint regression to estimate values of detrital stoichiometry that can potentially be used to indicate elevated breakdown rates. Breakpoint ratios for total breakdown were 41 (C:N) and 1518 (C:P), coinciding with total breakdown rates that were {\textasciitilde}1.9 times higher when C:N or C:P fell below these breakpoints. Microbial and shredder-mediated breakdown rates both increased when C:N and C:P were reduced, suggesting that detrital stoichiometry is useful for predicting litter breakdown dominated by either microbial or shredder activity. Our results show strong effects of nutrient enrichment on detrital stoichiometry and offer a robust link between a potential holistic nutrient loading metric (decreased and homogenized detrital stoichiometry) and increased C loss from stream ecosystems.},
	number = {6},
	journal = {Ecological Applications},
	author = {Manning, D.W.P. and Rosemond, A.D. and Gulis, V. and Benstead, J.P. and Kominoski, J.S. and Maerz, J.C.},
	year = {2016},
	keywords = {Breakpoint regression, Car, [Appalachian mountains},
	pages = {1745--1757},
}

Nutrient enrichment of detritus-based streams increases detrital resource quality for consumers and stimulates breakdown rates of particulate organic carbon (C). The relative importance of dissolved inorganic nitrogen (N) vs. phosphorus (P) for detrital quality and their effects on microbial- vs. detritivore-mediated detrital breakdown are poorly understood. We tested effects of experimental N and P additions on detrital stoichiometry (C:N, C:P) and total and microbial breakdown (i.e., with and without detritivorous shredders, respectively) of five detritus types (four leaf litter species and wood) with different initial C: nutrient content. We enriched five headwater streams continuously for two years at different relative availabilities of N and P and compared breakdown rates and detrital stoichiometry to pretreatment conditions. Total breakdown rates increased with nutrient enrichment and were predicted by altered detrital stoichiometry. Streamwater N and P, fungal biomass, and their interactions affected stoichiometry of detritus. Streamwater N and P decreased detrital C:N, whereas streamwater P had stronger negative effects on detrital C:P. Nutrient addition and fungal biomass reduced C:N by 70% and C:P by 83% on average after conditioning, compared to only 26% for C:N and 10% for C:P under pretreatment conditions. Detritus with lowest initial nutrient content changed the most and had greatest increases in total breakdown rates. Detrital stoichiometry was reduced and differences among detritus types were homogenized by nutrient enrichment. With enrichment, detrital nutrient content approached detritivore nutritional requirements and stimulated greater detritivore vs. microbial litter breakdown. We used breakpoint regression to estimate values of detrital stoichiometry that can potentially be used to indicate elevated breakdown rates. Breakpoint ratios for total breakdown were 41 (C:N) and 1518 (C:P), coinciding with total breakdown rates that were ~1.9 times higher when C:N or C:P fell below these breakpoints. Microbial and shredder-mediated breakdown rates both increased when C:N and C:P were reduced, suggesting that detrital stoichiometry is useful for predicting litter breakdown dominated by either microbial or shredder activity. Our results show strong effects of nutrient enrichment on detrital stoichiometry and offer a robust link between a potential holistic nutrient loading metric (decreased and homogenized detrital stoichiometry) and increased C loss from stream ecosystems.

@article{murphy_evaporative_2016,
	title = {Evaporative {Water} {Loss} {Rates} of {Four} {Species} of {Aquatic} {Turtles} from the {Coastal} {Plain} of the {Southeastern} {United} {States}},
	volume = {50},
	copyright = {All rights reserved},
	doi = {10.1670/15-124},
	abstract = {Many isolated wetlands in the southeastern United States are naturally ephemeral, productive habitats that can support a high diversity of aquatic reptiles. As wetlands begin to dry, reptile species exhibit different behavioral responses including overland dispersal and terrestrial aestivation. Regardless of strategy, one of the greatest risks to individual survival is desiccation. We measured evaporative water loss rates (EWL; \% body mass lost per hour) and total \% body mass lost over 24 h in four species of semiaquatic turtles that frequent isolated wetlands in the southeastern United States: Chicken Turtles (Deirochelys reticularia), Eastern Mud Turtles (Kinosternon subrubrum), Common Musk Turtles (Sternotherus odoratus), and Yellow-Bellied Sliders (Trachemys scripta scripta). Mean percent body mass lost over 24 h ranged from 4.44–10.26\% among individuals, was negatively correlated with body mass and varied among species, with higher EWL rates occurring in species with reduced shell robustness (the amount of the body covered by the shell). Mean EWL rates were highest in S. odoratus, lowest in K. subrubrum, and intermediate in D. reticularia and T. scripta. The EWL rates corresponded to species’ natural history traits and behavioral adaptations to drought. Species with higher EWL rates could be more vulnerable to increased drought duration and frequency resulting from either climate change or anthropogenic modification of wetland hydrology, and easily measured traits such as shell robustness and body mass may be useful in predicting EWL rates and desiccation risk for particular age classes and other species of turtles.},
	number = {3},
	journal = {Journal of Herpetology},
	author = {Murphy, C.M. and Tuberville, T.D. and Maerz, J.C. and Andrews, K.M.},
	year = {2016},
	pages = {457--463},
}

Many isolated wetlands in the southeastern United States are naturally ephemeral, productive habitats that can support a high diversity of aquatic reptiles. As wetlands begin to dry, reptile species exhibit different behavioral responses including overland dispersal and terrestrial aestivation. Regardless of strategy, one of the greatest risks to individual survival is desiccation. We measured evaporative water loss rates (EWL; % body mass lost per hour) and total % body mass lost over 24 h in four species of semiaquatic turtles that frequent isolated wetlands in the southeastern United States: Chicken Turtles (Deirochelys reticularia), Eastern Mud Turtles (Kinosternon subrubrum), Common Musk Turtles (Sternotherus odoratus), and Yellow-Bellied Sliders (Trachemys scripta scripta). Mean percent body mass lost over 24 h ranged from 4.44–10.26% among individuals, was negatively correlated with body mass and varied among species, with higher EWL rates occurring in species with reduced shell robustness (the amount of the body covered by the shell). Mean EWL rates were highest in S. odoratus, lowest in K. subrubrum, and intermediate in D. reticularia and T. scripta. The EWL rates corresponded to species’ natural history traits and behavioral adaptations to drought. Species with higher EWL rates could be more vulnerable to increased drought duration and frequency resulting from either climate change or anthropogenic modification of wetland hydrology, and easily measured traits such as shell robustness and body mass may be useful in predicting EWL rates and desiccation risk for particular age classes and other species of turtles.

@article{pierson_detection_2016,
	title = {Detection of an enigmatic plethodontid salamander using environmental {DNA}},
	volume = {2016},
	copyright = {All rights reserved},
	doi = {10.1643/CH-14-202},
	abstract = {The isolation and identification of environmental DNA (eDNA) offers a non-invasive and efficient method for the detection of rare and secretive aquatic wildlife, and it is being widely integrated into inventory and monitoring efforts. The Patch-Nosed Salamander (Urspelerpes brucei) is a tiny, recently discovered species of plethodontid salamander known only from headwater streams in a small region of Georgia and South Carolina. Here, we present results of a quantitative PCR-based eDNA assay capable of detecting Urspelerpes in more than 75\% of 33 samples from five confirmed streams. We deployed the method at 31 additional streams and located three previously undocumented populations of Urspelerpes. We compare the results of our eDNA assay with our attempt to use aquatic leaf litterbags for the rapid detection of Urspelerpes and demonstrate the relative efficacy of the eDNA assay. We suggest that eDNA offers great potential for use in detecting other aquatic and semi-aquatic plethodontid salamanders.},
	number = {1},
	journal = {Copeia},
	author = {Pierson, T.W. and McKee, A.M. and Spear, S.F. and Maerz, J.C. and Camp, C.D. and Glenn, T.C.},
	year = {2016},
	pages = {78--82},
}

The isolation and identification of environmental DNA (eDNA) offers a non-invasive and efficient method for the detection of rare and secretive aquatic wildlife, and it is being widely integrated into inventory and monitoring efforts. The Patch-Nosed Salamander (Urspelerpes brucei) is a tiny, recently discovered species of plethodontid salamander known only from headwater streams in a small region of Georgia and South Carolina. Here, we present results of a quantitative PCR-based eDNA assay capable of detecting Urspelerpes in more than 75% of 33 samples from five confirmed streams. We deployed the method at 31 additional streams and located three previously undocumented populations of Urspelerpes. We compare the results of our eDNA assay with our attempt to use aquatic leaf litterbags for the rapid detection of Urspelerpes and demonstrate the relative efficacy of the eDNA assay. We suggest that eDNA offers great potential for use in detecting other aquatic and semi-aquatic plethodontid salamanders.

@article{cecala_context-dependent_2016,
	title = {Context-dependent responses to light contribute to responses by {Black}-bellied {Salamanders} ({Desmognathusquadramaculatus}) to landscape disturbances},
	volume = {94},
	copyright = {All rights reserved},
	issn = {0008-4301 1480-3283},
	doi = {10.1139/cjz-2015-0111},
	abstract = {Behaviour often regulates population responses to environmental change, but linking behavioural responses to population patterns can be challenging because behavioural responses are often context-dependent, have an instinctive component, and yet may be modified by experience. Black-bellied Salamanders (Desmognathus quadramaculatus (Holbrook, 1840)) occupy forested streams where dense canopies create cool, dark environments. Because riparian deforestation negatively affects salamander-population connectivity yet some individuals choose to persist in these gaps, we sought to evaluate whether phototaxis could explain these patterns and whether phototactic behaviour would be influenced by experience (capture from forested or deforested areas) or context (refuge type and availability). Our results demonstrated that larval D. quadramaculatus exhibited negative phototaxis, but that larvae from forested streams exhibited stronger negative phototaxis than individuals from deforested streams. Larvae also selected habitat closer to light when refuge was available. Our results show that light alters habitat use by larval D. quadramaculatus, but the magnitude of that effect depends on refuge availability and experience with well-lit conditions associated with forest removal. As human activities reduce canopy cover and refuge availability, negative phototaxis may be one explanation for behavioural barriers to movement. Ultimately, the ability of salamanders to exhibit behavioural plasticity will determine their potential for local adaptation facilitating persistence in the face of environmental change.},
	number = {1},
	journal = {Canadian Journal of Zoology},
	author = {Cecala, K K and Maerz, J C},
	year = {2016},
	pages = {7--13},
}

Behaviour often regulates population responses to environmental change, but linking behavioural responses to population patterns can be challenging because behavioural responses are often context-dependent, have an instinctive component, and yet may be modified by experience. Black-bellied Salamanders (Desmognathus quadramaculatus (Holbrook, 1840)) occupy forested streams where dense canopies create cool, dark environments. Because riparian deforestation negatively affects salamander-population connectivity yet some individuals choose to persist in these gaps, we sought to evaluate whether phototaxis could explain these patterns and whether phototactic behaviour would be influenced by experience (capture from forested or deforested areas) or context (refuge type and availability). Our results demonstrated that larval D. quadramaculatus exhibited negative phototaxis, but that larvae from forested streams exhibited stronger negative phototaxis than individuals from deforested streams. Larvae also selected habitat closer to light when refuge was available. Our results show that light alters habitat use by larval D. quadramaculatus, but the magnitude of that effect depends on refuge availability and experience with well-lit conditions associated with forest removal. As human activities reduce canopy cover and refuge availability, negative phototaxis may be one explanation for behavioural barriers to movement. Ultimately, the ability of salamanders to exhibit behavioural plasticity will determine their potential for local adaptation facilitating persistence in the face of environmental change.

@article{satterfield_migratory_2016,
	title = {Migratory monarchs wintering in {California} experience low infection risk compared to monarchs breeding year-round on non-native milkweed},
	volume = {56},
	copyright = {All rights reserved},
	issn = {1557-7023 (Electronic) 1540-7063 (Linking)},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/27252207},
	doi = {10.1093/icb/icw030},
	abstract = {Long-distance migration can lower infection risk for animal populations by removing infected individuals during strenuous journeys, spatially separating susceptible age classes, or allowing migrants to periodically escape from contaminated habitats. Many seasonal migrations are changing due to human activities including climate change and habitat alteration. Moreover, for some migratory populations, sedentary behaviors are becoming more common as migrants abandon or shorten their journeys in response to supplemental feeding or warming temperatures. Exploring the consequences of reduced movement for host-parasite interactions is needed to predict future responses of animal pathogens to anthropogenic change. Monarch butterflies (Danaus plexippus) and their specialist protozoan parasite Ophryocystis elektroscirrha (OE) provide a model system for examining how long-distance migration affects infectious disease processes in a rapidly changing world. Annual monarch migration from eastern North America to Mexico is known to reduce protozoan infection prevalence, and more recent work suggests that monarchs that forego migration to breed year-round on non-native milkweeds in the southeastern and south central Unites States face extremely high risk of infection. Here, we examined the prevalence of OE infection from 2013 to 2016 in western North America, and compared monarchs exhibiting migratory behavior (overwintering annually along the California coast) with those that exhibit year-round breeding. Data from field collections and a joint citizen science program of Monarch Health and Monarch Alert showed that infection frequency was over nine times higher for monarchs sampled in gardens with year-round milkweed as compared to migratory monarchs sampled at overwintering sites. Results here underscore the importance of animal migrations for lowering infection risk and motivate future studies of pathogen transmission in migratory species affected by environmental change.},
	number = {2},
	journal = {Integr Comp Biol},
	author = {Satterfield, D A and Villablanca, F X and Maerz, J C and Altizer, S},
	year = {2016},
	pages = {343--352},
}

Long-distance migration can lower infection risk for animal populations by removing infected individuals during strenuous journeys, spatially separating susceptible age classes, or allowing migrants to periodically escape from contaminated habitats. Many seasonal migrations are changing due to human activities including climate change and habitat alteration. Moreover, for some migratory populations, sedentary behaviors are becoming more common as migrants abandon or shorten their journeys in response to supplemental feeding or warming temperatures. Exploring the consequences of reduced movement for host-parasite interactions is needed to predict future responses of animal pathogens to anthropogenic change. Monarch butterflies (Danaus plexippus) and their specialist protozoan parasite Ophryocystis elektroscirrha (OE) provide a model system for examining how long-distance migration affects infectious disease processes in a rapidly changing world. Annual monarch migration from eastern North America to Mexico is known to reduce protozoan infection prevalence, and more recent work suggests that monarchs that forego migration to breed year-round on non-native milkweeds in the southeastern and south central Unites States face extremely high risk of infection. Here, we examined the prevalence of OE infection from 2013 to 2016 in western North America, and compared monarchs exhibiting migratory behavior (overwintering annually along the California coast) with those that exhibit year-round breeding. Data from field collections and a joint citizen science program of Monarch Health and Monarch Alert showed that infection frequency was over nine times higher for monarchs sampled in gardens with year-round milkweed as compared to migratory monarchs sampled at overwintering sites. Results here underscore the importance of animal migrations for lowering infection risk and motivate future studies of pathogen transmission in migratory species affected by environmental change.

@article{bumpers_salamander_2015,
	title = {Salamander growth rates increase along an experimental stream phosphorus gradient},
	volume = {96},
	copyright = {All rights reserved},
	doi = {10.1890/14-1772.1.sm},
	abstract = {Nutrient-driven perturbations to the resource base of food webs are predicted to attenuate with trophic distance, so it is unclear whether higher-level consumers will generally respond to anthropogenic nutrient loading. Few studies have tested whether nutrient (specifically, nitrogen [N] and phosphorus [P]) enrichment of aquatic ecosystems propagates through multiple trophic levels to affect predators, or whether N vs. P is relatively more important in driving effects on food webs. We conducted two-year whole-stream N and P additions to five streams to generate gradients in N and P concentration and N:P ratio (target N:P ¼ 2, 8, 16, 32, 128). Larval salamanders are vertebrate predators of primary and secondary macroinvertebrate consumers in many heterotrophic headwater streams in which the basal resources are detritus and associated microorganisms. We determined the effects of N and P on the growth rates of caged and free-roaming larval Desmognathus quadramaculatus and the average body size of larval Eurycea wilderae. Growth rates and average body size increased by up to 40\% and 60\%, respectively, with P concentration and were negatively related to N:P ratio. These findings were consistent across both species of salamanders using different methodologies (cage vs. free-roaming) and at different temporal scales (3 months vs. 2 yr). Nitrogen concentration was not significantly related to increased growth rate or body size of the salamander species tested. Our findings suggest that salamander growth responds to the relaxation of ecosystem-level P limitation and that moderate P enrichment can have relatively large effects on vertebrate predators in detritus-based food webs.},
	number = {11},
	journal = {Ecology},
	author = {Bumpers, P.M. and Maerz, J.C. and Rosemond, A.D. and Benstead, J.P.},
	year = {2015},
	keywords = {Desmognathus, Detritus, Ecological sto, [Bottom-up},
	pages = {2994--3004},
}

Nutrient-driven perturbations to the resource base of food webs are predicted to attenuate with trophic distance, so it is unclear whether higher-level consumers will generally respond to anthropogenic nutrient loading. Few studies have tested whether nutrient (specifically, nitrogen [N] and phosphorus [P]) enrichment of aquatic ecosystems propagates through multiple trophic levels to affect predators, or whether N vs. P is relatively more important in driving effects on food webs. We conducted two-year whole-stream N and P additions to five streams to generate gradients in N and P concentration and N:P ratio (target N:P ¼ 2, 8, 16, 32, 128). Larval salamanders are vertebrate predators of primary and secondary macroinvertebrate consumers in many heterotrophic headwater streams in which the basal resources are detritus and associated microorganisms. We determined the effects of N and P on the growth rates of caged and free-roaming larval Desmognathus quadramaculatus and the average body size of larval Eurycea wilderae. Growth rates and average body size increased by up to 40% and 60%, respectively, with P concentration and were negatively related to N:P ratio. These findings were consistent across both species of salamanders using different methodologies (cage vs. free-roaming) and at different temporal scales (3 months vs. 2 yr). Nitrogen concentration was not significantly related to increased growth rate or body size of the salamander species tested. Our findings suggest that salamander growth responds to the relaxation of ecosystem-level P limitation and that moderate P enrichment can have relatively large effects on vertebrate predators in detritus-based food webs.

@article{crawford_when_2015,
	title = {When drivers and terrapins collide: {Assessing} stakeholder attitudes toward wildlife management on the {Jekyll} {Island} causeway},
	volume = {20},
	copyright = {All rights reserved},
	doi = {10.1080/10871209.2014.948103},
	abstract = {Roads are a pervasive fixture on most landscapes and frequently impact wildlife. Management of road effects on wildlife should consider the attitudes and areas of contention among various stakeholders using the road. To inform future management of road impacts on the diamondback terrapin (Malaclemys terrapin), a species of conservation concern, we surveyed stakeholder groups on Jekyll Island, Georgia, USA to measure overall attitudes and value orientations relating to terrapin management and to evaluate the acceptability and potential for conflict among user groups regarding specific management alternatives. A majority of respondents supported the protection of terrapins, although support varied by group membership and value orientation. Specific actions that did not impact speed limits or road aesthetics were most acceptable, but substantial conflict existed for most strategies. We intend to use these results to improve communication and buy-in of stakeholders as we develop management alternatives for the diamondback terrapin on Jekyll Island.},
	journal = {Human Dimensions of Wildlife},
	author = {Crawford, B.A. and Poudyal, N.C. and Maerz, J.C.},
	year = {2015},
	keywords = {attitudes, diamondback terrapin (Malaclemys terrapin), potential for conflict index, road management},
	pages = {1--14},
}

Roads are a pervasive fixture on most landscapes and frequently impact wildlife. Management of road effects on wildlife should consider the attitudes and areas of contention among various stakeholders using the road. To inform future management of road impacts on the diamondback terrapin (Malaclemys terrapin), a species of conservation concern, we surveyed stakeholder groups on Jekyll Island, Georgia, USA to measure overall attitudes and value orientations relating to terrapin management and to evaluate the acceptability and potential for conflict among user groups regarding specific management alternatives. A majority of respondents supported the protection of terrapins, although support varied by group membership and value orientation. Specific actions that did not impact speed limits or road aesthetics were most acceptable, but substantial conflict existed for most strategies. We intend to use these results to improve communication and buy-in of stakeholders as we develop management alternatives for the diamondback terrapin on Jekyll Island.

@article{groffman_earthworms_2015,
	title = {Earthworms increase soil microbial biomass carrying capacity and nitrogen retention in northern hardwood forests},
	volume = {87},
	copyright = {All rights reserved},
	doi = {10.1016/j.soilbio.2015.03.025},
	abstract = {Earthworms have been shown to produce contrasting effects on soil carbon (C) and nitrogen (N) pools and dynamics. We measured soil C and N pools and processes and traced the flow of 13Cand15N from sugar maple (Acer saccharum Marsh.) litter into soil microbial biomass and respirable C and mineralizable and inorganic N pools in mature northern hardwood forest plots with variable earthworm communities. Previous studies have shown that plots dominated by either Lumbricus rubellus or Lumbricus terrestris have markedly lower total soil C than uncolonized plots. Here we show that total soil N pools in earthworm colonized plots were reduced much less than C, but significantly so in plots dominated by contain L. rubellus. Pools of microbial biomass C and N were higher in earthworm-colonized (especially those dominated by L. rubellus) plots and more 13C and 15N were recovered in microbial biomass and less was recovered in mineralizable and inorganic N pools in these plots. These plots also had lower rates of potential net N mineralization and nitrification than uncolonized reference plots. These results suggest that earthworm stimulation of microbial biomass and activity underlie depletion of soil C and retention and maintenance of soil N pools, at least in northern hardwood forests. Earthworms increase the carrying capacity of soil for microbial biomass and facilitate the flow of N from litter into stable soil organic matter. However, declines in soil C and C:N ratio may increase the potential for hydrologic and gaseous losses in earthworm-colonized sites under changing environmental conditions.},
	journal = {Soil Biology and Biochemistry},
	author = {Groffman, Peter M. and Fahey, Timothy J. and Fisk, Melany C. and Yavitt, Joseph B. and Sherman, Ruth E. and Bohlen, Patrick J. and Maerz, John C.},
	year = {2015},
	keywords = {Earthworms, Isotopes, Microbial biomass, [Carbon},
	pages = {51--58},
}

Earthworms have been shown to produce contrasting effects on soil carbon (C) and nitrogen (N) pools and dynamics. We measured soil C and N pools and processes and traced the flow of 13Cand15N from sugar maple (Acer saccharum Marsh.) litter into soil microbial biomass and respirable C and mineralizable and inorganic N pools in mature northern hardwood forest plots with variable earthworm communities. Previous studies have shown that plots dominated by either Lumbricus rubellus or Lumbricus terrestris have markedly lower total soil C than uncolonized plots. Here we show that total soil N pools in earthworm colonized plots were reduced much less than C, but significantly so in plots dominated by contain L. rubellus. Pools of microbial biomass C and N were higher in earthworm-colonized (especially those dominated by L. rubellus) plots and more 13C and 15N were recovered in microbial biomass and less was recovered in mineralizable and inorganic N pools in these plots. These plots also had lower rates of potential net N mineralization and nitrification than uncolonized reference plots. These results suggest that earthworm stimulation of microbial biomass and activity underlie depletion of soil C and retention and maintenance of soil N pools, at least in northern hardwood forests. Earthworms increase the carrying capacity of soil for microbial biomass and facilitate the flow of N from litter into stable soil organic matter. However, declines in soil C and C:N ratio may increase the potential for hydrologic and gaseous losses in earthworm-colonized sites under changing environmental conditions.

@article{grosse_effects_2015,
	title = {Effects of vegetation structure and artificial nesting habitats on hatchling sex determination and nest survival of diamondback terrapins},
	volume = {6},
	copyright = {All rights reserved},
	doi = {10.3996/082014-JFWM-063},
	abstract = {It is often the case that multiple factors contribute to wildlife population declines such that management will require simultaneous, integrated interventions to stabilize and recover populations. Diamondback terrapins Malaclemys terrapin are a species of high conservation priority, and local populations can be threatened by multiple factors, including bycatch in commercial and recreational crab pots, vehicle strikes on coastal roads, nest depredation from subsidized and introduced predators, and terrestrial habitat alteration. Mitigation of just one of these factors will often be insufficient for recovering at-risk populations; thus, information to manage multiple threats is needed. We measured the effects of natural vegetation structure and constructed (artificial) nesting habitat on hatchling sex ratios and nest depredation for a declining terrapin population on Jekyll Island, Georgia. Nest temperatures were highest on constructed nesting mounds, intermediate in open grass areas, and coolest under the shrub-dominated hedgerows. Higher nest temperatures led to shorter incubation times for nests on mounds and open habitat, such that all surviving nests on nesting mounds and open areas produced female hatchlings. In contrast, surviving nests under hedge produced 85\% male hatchlings. Raccoon Procyon lotor predation rates of simulated (chicken egg) nests were highest on nesting mounds (95.3\%), followed by hedge (84.4\%) and open habitats (45.2\%). Our results demonstrate that vegetation management can positively affect both production of female hatchlings and nest survival. Artificial nest mounds were successful at producing female hatchlings, but we documented high predation of simulated (chicken egg) nests despite structures to exclude predators. Further modifications to nest boxes atop constructed nesting mounds are needed for these devices to effectively contribute to population management. We suggest the relatively low cost and maintenance associated with removing shrubs and trees can be a viable strategy to manage large areas of nesting habitat for the increased production of female turtles, and to reduce the impacts of subsidized predators.},
	number = {1},
	journal = {Journal of Fish and Wildlife Management},
	author = {Grosse, A.M. and Crawford, B.A. and Maerz, J.C. and Buhlmann, K.A. and Norton, T. and Kaylor, M. and Tuberville, T.D.},
	year = {2015},
	keywords = {Diamondback terrapin, Nest survival, Nesting habitat, Predation, Sex determination},
	pages = {19--28},
}

It is often the case that multiple factors contribute to wildlife population declines such that management will require simultaneous, integrated interventions to stabilize and recover populations. Diamondback terrapins Malaclemys terrapin are a species of high conservation priority, and local populations can be threatened by multiple factors, including bycatch in commercial and recreational crab pots, vehicle strikes on coastal roads, nest depredation from subsidized and introduced predators, and terrestrial habitat alteration. Mitigation of just one of these factors will often be insufficient for recovering at-risk populations; thus, information to manage multiple threats is needed. We measured the effects of natural vegetation structure and constructed (artificial) nesting habitat on hatchling sex ratios and nest depredation for a declining terrapin population on Jekyll Island, Georgia. Nest temperatures were highest on constructed nesting mounds, intermediate in open grass areas, and coolest under the shrub-dominated hedgerows. Higher nest temperatures led to shorter incubation times for nests on mounds and open habitat, such that all surviving nests on nesting mounds and open areas produced female hatchlings. In contrast, surviving nests under hedge produced 85% male hatchlings. Raccoon Procyon lotor predation rates of simulated (chicken egg) nests were highest on nesting mounds (95.3%), followed by hedge (84.4%) and open habitats (45.2%). Our results demonstrate that vegetation management can positively affect both production of female hatchlings and nest survival. Artificial nest mounds were successful at producing female hatchlings, but we documented high predation of simulated (chicken egg) nests despite structures to exclude predators. Further modifications to nest boxes atop constructed nesting mounds are needed for these devices to effectively contribute to population management. We suggest the relatively low cost and maintenance associated with removing shrubs and trees can be a viable strategy to manage large areas of nesting habitat for the increased production of female turtles, and to reduce the impacts of subsidized predators.

@article{manning_detrital_2015,
	title = {Detrital stoichiometry as a critical nexus for the effects of streamwater nutrients on leaf litter breakdown rates},
	volume = {96},
	copyright = {All rights reserved},
	abstract = {Nitrogen (N) and phosphorus (P) concentrations are elevated in many freshwater systems, stimulating breakdown rates of terrestrially derived plant litter; however, the relative importance of N and P in driving litter breakdown via microbial and detritivore processing are not fully understood. Here, we determined breakdown rates of two litter species, Acer rubrum (maple) and Rhododendron maximum (rhododendron), before (PRE) and during two years (YR1, YR2) of experimental N and P additions to five streams, and quantified the relative importance of hypothesized factors contributing to breakdown. Treatment streams received a gradient of P additions (low to high soluble reactive phosphorus [SRP]; ;10–85 lg/L) crossed with a gradient of N additions (high to low dissolved inorganic nitrogen [DIN]; ;472–96 lg/L) to achieve target molar N:P ratios ranging from 128 to 2. Litter breakdown rates increased above pre-treatment levels by an average of 1.1–2.23 for maple, and 2.7–4.93 for rhododendron in YR1 and YR2. We used path analysis to compare fungal biomass, shredder biomass, litter stoichiometry (nutrient content as C:N or C:P), discharge, and streamwater temperature as predictors of breakdown rates and compared models containing streamwater N, P or N þ P and litter C:N or C:P using model selection criteria. Litter breakdown rates were predicted equally with either streamwater N or P (R2 ¼ 0.57). In models with N or P, fungal biomass, litter stoichiometry, discharge, and shredder biomass predicted breakdown rates; litter stoichiometry and fungal biomass were most important for model fit. However, N and P effects may have occurred via subtly different pathways. Litter N content increased with fungal biomass (N-driven effects) and litter P content increased with streamwater P availability (P-driven effects), presumably via P storage in fungal biomass. In either case, the effects of N and P through these pathways were associated with higher shredder biomass and breakdown rates. Our results suggest that N and P stimulate litter breakdown rates via mechanisms in which litter stoichiometry is an important nexus for associated microbial and detritivore effects.},
	number = {8},
	journal = {Ecology},
	author = {Manning, D.W.P. and Rosemond, A.D. and Kominoski, J.S. and Gulis, V. and Benstead, J.P. and Maerz, J.C.},
	year = {2015},
	keywords = {Decomposition, Detritus, Ecological, [Carbon loss},
	pages = {2214--2224},
}

Nitrogen (N) and phosphorus (P) concentrations are elevated in many freshwater systems, stimulating breakdown rates of terrestrially derived plant litter; however, the relative importance of N and P in driving litter breakdown via microbial and detritivore processing are not fully understood. Here, we determined breakdown rates of two litter species, Acer rubrum (maple) and Rhododendron maximum (rhododendron), before (PRE) and during two years (YR1, YR2) of experimental N and P additions to five streams, and quantified the relative importance of hypothesized factors contributing to breakdown. Treatment streams received a gradient of P additions (low to high soluble reactive phosphorus [SRP]; ;10–85 lg/L) crossed with a gradient of N additions (high to low dissolved inorganic nitrogen [DIN]; ;472–96 lg/L) to achieve target molar N:P ratios ranging from 128 to 2. Litter breakdown rates increased above pre-treatment levels by an average of 1.1–2.23 for maple, and 2.7–4.93 for rhododendron in YR1 and YR2. We used path analysis to compare fungal biomass, shredder biomass, litter stoichiometry (nutrient content as C:N or C:P), discharge, and streamwater temperature as predictors of breakdown rates and compared models containing streamwater N, P or N þ P and litter C:N or C:P using model selection criteria. Litter breakdown rates were predicted equally with either streamwater N or P (R2 ¼ 0.57). In models with N or P, fungal biomass, litter stoichiometry, discharge, and shredder biomass predicted breakdown rates; litter stoichiometry and fungal biomass were most important for model fit. However, N and P effects may have occurred via subtly different pathways. Litter N content increased with fungal biomass (N-driven effects) and litter P content increased with streamwater P availability (P-driven effects), presumably via P storage in fungal biomass. In either case, the effects of N and P through these pathways were associated with higher shredder biomass and breakdown rates. Our results suggest that N and P stimulate litter breakdown rates via mechanisms in which litter stoichiometry is an important nexus for associated microbial and detritivore effects.

@article{milanovich_stoichiometry_2015,
	title = {Stoichiometry and estimates of nutrient standing stocks of larval salamanders in {Appalachian} headwater streams},
	volume = {60},
	copyright = {All rights reserved},
	doi = {10.1111/fwb.12572},
	abstract = {Summary: Because of their longevity and skeletal phosphorus demand, vertebrates can have distinct influences on the uptake, storage and recycling of nutrients in ecosystems. Quantification of body stoichiometry, combined with estimates of abundance or biomass, can provide insights into the effect of vertebrates on nutrient cycling. We measured the nutrient content and estimated the abundance and biomass of the larvae of three salamander species to characterise the factors that influence larval salamander stoichiometry and estimate the contribution of larval salamanders to nutrient standing stock and recycling in five southern Appalachian headwaters. The proportion and ratios of carbon (C), nitrogen (N), phosphorus (P) and calcium (Ca) in larval salamanders varied with size within and among species. We found negative relationships between body size and whole-body \%N, C : P and N : P and positive relationships between body size and whole-body \%P and C : N. Mean estimated larval salamander density was 58 m-2 and mean estimated dry biomass was 2813 mg m-2. Estimated standing stock of N, P and Ca were 332, 81 and 103 mg m-2, respectively, which was 1.1 ? and 4.6 ? greater than estimated amounts of N and P reported for macroinvertebrate taxa in similar streams within the region and was higher than in many other consumers in freshwater habitats. Using data from previous studies, we estimate that the mean ingestion rate of N and P by plethodontids is 0.000001 and 0.00001 g-1 day-1, respectively, while excretion rates of both are {\textless}0.00001 g day-1. Salamanders are the only abundant vertebrates within headwater Appalachian streams, and our results show that larval salamanders represent a large standing stock of N, P and Ca in these streams. These findings complement other recent research demonstrating the effects of larval stream salamanders on macroinvertebrate abundance and seasonal nutrient supply in Appalachian headwaters and stress the importance of plethodontid salamanders to headwater stream processes.},
	journal = {Freshwater Biology},
	author = {Milanovich, J.R. and Maerz, J.C. and Rosemond, A.D.},
	year = {2015},
	keywords = {Density, Ecological role, Plethodontid, [Biomass},
	pages = {12572},
}

Summary: Because of their longevity and skeletal phosphorus demand, vertebrates can have distinct influences on the uptake, storage and recycling of nutrients in ecosystems. Quantification of body stoichiometry, combined with estimates of abundance or biomass, can provide insights into the effect of vertebrates on nutrient cycling. We measured the nutrient content and estimated the abundance and biomass of the larvae of three salamander species to characterise the factors that influence larval salamander stoichiometry and estimate the contribution of larval salamanders to nutrient standing stock and recycling in five southern Appalachian headwaters. The proportion and ratios of carbon (C), nitrogen (N), phosphorus (P) and calcium (Ca) in larval salamanders varied with size within and among species. We found negative relationships between body size and whole-body %N, C : P and N : P and positive relationships between body size and whole-body %P and C : N. Mean estimated larval salamander density was 58 m-2 and mean estimated dry biomass was 2813 mg m-2. Estimated standing stock of N, P and Ca were 332, 81 and 103 mg m-2, respectively, which was 1.1 ? and 4.6 ? greater than estimated amounts of N and P reported for macroinvertebrate taxa in similar streams within the region and was higher than in many other consumers in freshwater habitats. Using data from previous studies, we estimate that the mean ingestion rate of N and P by plethodontids is 0.000001 and 0.00001 g-1 day-1, respectively, while excretion rates of both are \textless0.00001 g day-1. Salamanders are the only abundant vertebrates within headwater Appalachian streams, and our results show that larval salamanders represent a large standing stock of N, P and Ca in these streams. These findings complement other recent research demonstrating the effects of larval stream salamanders on macroinvertebrate abundance and seasonal nutrient supply in Appalachian headwaters and stress the importance of plethodontid salamanders to headwater stream processes.

@article{satterfield_loss_2015,
	title = {Loss of migratory behaviour increases infection risk for a butterfly host},
	volume = {282},
	copyright = {All rights reserved},
	doi = {10.1098/rspb.2014.1734},
	abstract = {Long-distance animal migrations have important consequences for infectious disease dynamics. In some cases, migration lowers pathogen transmission by removing infected individuals during strenuous journeys and allowing animals to periodically escape contaminated habitats. Human activities are now causing some migratory animals to travel shorter distances or form sedentary (non-migratory) populations. We focused on North American monarch butterflies and a specialist protozoan parasite to investigate how the loss of migratory behaviours affects pathogen spread and evolution. Each autumn, monarchs migrate from breeding grounds in the eastern US and Canada to wintering sites in central Mexico. However, some monarchs have become non-migratory and breed year-round on exotic milkweed in the southern US. We used field sampling, citizen science data and experimental inoculations to quantify infection prevalence and parasite virulence among migratory and sedentary populations. Infection prevalence was markedly higher among sedentary monarchs compared with migratory monarchs, indicating that diminished migration increases infection risk. Virulence differed among parasite strains but was similar between migratory and sedentary populations, potentially owing to high gene flow or insufficient time for evolutionary divergence. More broadly, our findings suggest that human activities that alter animal migrations can influence pathogen dynamics, with implications for wildlife conservation and future disease risks.},
	journal = {Proceedings of the Royal Society B: Biological Sciences},
	author = {Satterfield, D.A. and Maerz, J.C. and Altizer, S.},
	year = {2015},
	keywords = {Infectious disease, Long-distan, [Danaus plexippus},
	pages = {20141734},
}

Long-distance animal migrations have important consequences for infectious disease dynamics. In some cases, migration lowers pathogen transmission by removing infected individuals during strenuous journeys and allowing animals to periodically escape contaminated habitats. Human activities are now causing some migratory animals to travel shorter distances or form sedentary (non-migratory) populations. We focused on North American monarch butterflies and a specialist protozoan parasite to investigate how the loss of migratory behaviours affects pathogen spread and evolution. Each autumn, monarchs migrate from breeding grounds in the eastern US and Canada to wintering sites in central Mexico. However, some monarchs have become non-migratory and breed year-round on exotic milkweed in the southern US. We used field sampling, citizen science data and experimental inoculations to quantify infection prevalence and parasite virulence among migratory and sedentary populations. Infection prevalence was markedly higher among sedentary monarchs compared with migratory monarchs, indicating that diminished migration increases infection risk. Virulence differed among parasite strains but was similar between migratory and sedentary populations, potentially owing to high gene flow or insufficient time for evolutionary divergence. More broadly, our findings suggest that human activities that alter animal migrations can influence pathogen dynamics, with implications for wildlife conservation and future disease risks.

@article{sterrett_spatial_2015,
	title = {Spatial ecology of female {Barbour}'s {Map} {Turtles} ({Graptemys} barbouri) in {Ichawaynochaway} {Creek}, {Georgia}},
	volume = {103},
	copyright = {All rights reserved},
	doi = {10.1643/CH-13-162},
	abstract = {Quantifying patterns of habitat use by riverine species is logistically challenging, yet instream habitat characteristics are likely important in explaining the distribution of species. We integrated radiotelemetry and sonar habitat mapping to quantify instream habitat use by female Barbour’s Map Turtles (Graptemys barbouri) in Ichawaynochaway Creek, a tributary to the Flint River. We used logistic regression and a Bayesian information-theoretic approach to evaluate habitat use relative to habitat availability based on random locations. Over the two-year study period, turtles used an average of 839±199 m of creek length and exhibited site fidelity (mean 50\% kernel density = 0.23±0.05 ha). Substrate was generally more predictive of habitat use of female G. barbouri compared to large woody debris and water depth. Turtles generally used deeper habitats close to rocky-boulder and rocky-fine substrate with greater amounts of large woody debris. Estimates of home range size and habitat use found in this study improve our understanding of the spatial ecology of G. barbouri and provide a baseline for their habitat use in a relatively undisturbed section of stream. It is imperative to understand the spatial ecology of species, such as map turtles, that are particularly vulnerable to indirect effects of habitat modifications caused by impoundments, sedimentation, pollution, and snagging.},
	number = {2},
	journal = {Copeia},
	author = {Sterrett, S.C. and Kaeser, A.J. and Katz, R.A. and Smith, L.L. and Brock, J.C. and Maerz, J.C.},
	year = {2015},
	pages = {263--271},
}

Quantifying patterns of habitat use by riverine species is logistically challenging, yet instream habitat characteristics are likely important in explaining the distribution of species. We integrated radiotelemetry and sonar habitat mapping to quantify instream habitat use by female Barbour’s Map Turtles (Graptemys barbouri) in Ichawaynochaway Creek, a tributary to the Flint River. We used logistic regression and a Bayesian information-theoretic approach to evaluate habitat use relative to habitat availability based on random locations. Over the two-year study period, turtles used an average of 839±199 m of creek length and exhibited site fidelity (mean 50% kernel density = 0.23±0.05 ha). Substrate was generally more predictive of habitat use of female G. barbouri compared to large woody debris and water depth. Turtles generally used deeper habitats close to rocky-boulder and rocky-fine substrate with greater amounts of large woody debris. Estimates of home range size and habitat use found in this study improve our understanding of the spatial ecology of G. barbouri and provide a baseline for their habitat use in a relatively undisturbed section of stream. It is imperative to understand the spatial ecology of species, such as map turtles, that are particularly vulnerable to indirect effects of habitat modifications caused by impoundments, sedimentation, pollution, and snagging.

@article{sterrett_what_2015,
	title = {What can turtles teach us about the theory of ecological stoichiometry?},
	volume = {60},
	copyright = {All rights reserved},
	doi = {10.1111/fwb.12516},
	abstract = {1. Vertebrate skeletons have high phosphorus (P) content relative to other tissues. Variation in skeletal investment within and among species is hypothesised to predict variation in P demand, standing stock and recycling. These relationships have been examined among fish, but not in vertebrates with more robust skeletons, such as turtles. 

2. Our objectives were to (i) describe freshwater turtle stoichiometry relative to skeletal mass, (ii) compare turtle body and excreta stoichiometry to patterns among fish and (iii) relate turtle skeletal stoichiometry to turtle nutrient storage and recycling. 

3. Skeleton constituted 82\% of turtle dry mass. Total body \%P increased ontogenetically with turtle mass and 93\% of all P resided in the skeleton. Phosphorus storage within turtle assemblages was high (0.2–0.45 kg ha 1). Turtles excreted lower concentrations of P than fish. Excreta N:P was positively correlated with body N:P, suggesting that increased skeletal P investment was inversely related to P demand. 

4. Our results demonstrate that P stored in the bone of turtles can represent a large standing stock of P in fresh waters. Further, our work suggests skeletal investment alone is not sufficient to predict an animal’s P demand and, by extension, their effects on nutrient recycling. Instead, our results indicate P demand is determined by both skeletal investment and growth rate. Consequently, taxa with high body P, extreme longevity and slow growth rates, such as adult turtles, may serve as stable standing stocks of nutrients while also contributing proportionately to nutrient remineralisation.},
	number = {3},
	journal = {Freshwater Biology},
	author = {Sterrett, S.C. and Maerz, J.C. and Katz, R.A.},
	year = {2015},
	keywords = {Nutrient storage, Phosphorus, [Nutrient recycling},
	pages = {443--455},
}

1. Vertebrate skeletons have high phosphorus (P) content relative to other tissues. Variation in skeletal investment within and among species is hypothesised to predict variation in P demand, standing stock and recycling. These relationships have been examined among fish, but not in vertebrates with more robust skeletons, such as turtles. 2. Our objectives were to (i) describe freshwater turtle stoichiometry relative to skeletal mass, (ii) compare turtle body and excreta stoichiometry to patterns among fish and (iii) relate turtle skeletal stoichiometry to turtle nutrient storage and recycling. 3. Skeleton constituted 82% of turtle dry mass. Total body %P increased ontogenetically with turtle mass and 93% of all P resided in the skeleton. Phosphorus storage within turtle assemblages was high (0.2–0.45 kg ha 1). Turtles excreted lower concentrations of P than fish. Excreta N:P was positively correlated with body N:P, suggesting that increased skeletal P investment was inversely related to P demand. 4. Our results demonstrate that P stored in the bone of turtles can represent a large standing stock of P in fresh waters. Further, our work suggests skeletal investment alone is not sufficient to predict an animal’s P demand and, by extension, their effects on nutrient recycling. Instead, our results indicate P demand is determined by both skeletal investment and growth rate. Consequently, taxa with high body P, extreme longevity and slow growth rates, such as adult turtles, may serve as stable standing stocks of nutrients while also contributing proportionately to nutrient remineralisation.

@article{trice_diet_2015,
	title = {Diet composition of two larval headwater stream salamanders and spatial distribution of prey},
	volume = {60},
	copyright = {All rights reserved},
	doi = {10.1111/fwb.12669},
	abstract = {1. Interspecific overlap in resource use can determine the degree to which different presumed guild members have distinct or similar effects on ecosystem processes or responses to environmental change. Many headwater streams of North America support multiple species of larval salamanders commonly defined as a single guild that can influence macroinvertebrate communities and nutrient dynamics and are sensitive to stream alteration. 

2. We explored macroinvertebrate distributions in conjunction with stable isotope and gut content analyses of salamanders to examine similarities in diet between two sympatric larval salamander species (Desmognathus quadramaculatus and Eurycea cirrigera) in four headwater streams. We determined the degree to which larval salamanders used similar prey functional feeding groups (FFGs) and taxa and determined the primary source habitat (pools versus riffles) of prey. 

3. Stable isotopes of carbon (d13C) and nitrogen (d15N) suggest the two salamander species occupied similar trophic positions and individual-based stable isotope mixing models indicated similar use of macroinvertebrate predators and filterers by both species. Diet analyses were generally consistent with stable isotope results in identifying prey FFGs that composed the largest biomass of salamander diets. However, despite similarities in diet at the resolution of FFGs, there was little overlap in the specific taxa consumed by the two salamander species: 52 prey taxa were consumed over all samples, with only 16 taxa in common. Further, only five prey taxa were common in dominating diet biomass of both species; there was more overlap in taxa in terms of diet abundance. 

4. We assessed patterns in benthic macroinvertebrate biomass and compared the biomass of taxa that were in pools versus riffles to the biomass and abundance of taxa in salamander diets. Total macroinvertebrate biomass was generally higher in pools; however, the majority of salamander prey biomass was from riffle habitats, a trend that was stronger for D. quadramaculatus than for E. cirrigera. There was greater similarity in taxa comprising diet by abundance with the majority of prey items originating from pools. 

5. The larval salamander species used similar prey FFGs but differed significantly in specific prey taxa. We hypothesise that species differences in diets were most likely a function of differences in larval size and microhabitat use. Consequently, the treatment of larval salamanders as a guild is probably inadequate for predicting the effect of larval salamander diversity on some stream processes, and species may differ in how they respond to factors affecting prey assemblages.},
	number = {11},
	journal = {Freshwater Biology},
	author = {Trice, A.E. and Rosemond, A.D. and Maerz, J.C.},
	year = {2015},
	keywords = {Headwater stream, Mixing model, Salaman, [Food web},
	pages = {2424--2434},
}

1. Interspecific overlap in resource use can determine the degree to which different presumed guild members have distinct or similar effects on ecosystem processes or responses to environmental change. Many headwater streams of North America support multiple species of larval salamanders commonly defined as a single guild that can influence macroinvertebrate communities and nutrient dynamics and are sensitive to stream alteration. 2. We explored macroinvertebrate distributions in conjunction with stable isotope and gut content analyses of salamanders to examine similarities in diet between two sympatric larval salamander species (Desmognathus quadramaculatus and Eurycea cirrigera) in four headwater streams. We determined the degree to which larval salamanders used similar prey functional feeding groups (FFGs) and taxa and determined the primary source habitat (pools versus riffles) of prey. 3. Stable isotopes of carbon (d13C) and nitrogen (d15N) suggest the two salamander species occupied similar trophic positions and individual-based stable isotope mixing models indicated similar use of macroinvertebrate predators and filterers by both species. Diet analyses were generally consistent with stable isotope results in identifying prey FFGs that composed the largest biomass of salamander diets. However, despite similarities in diet at the resolution of FFGs, there was little overlap in the specific taxa consumed by the two salamander species: 52 prey taxa were consumed over all samples, with only 16 taxa in common. Further, only five prey taxa were common in dominating diet biomass of both species; there was more overlap in taxa in terms of diet abundance. 4. We assessed patterns in benthic macroinvertebrate biomass and compared the biomass of taxa that were in pools versus riffles to the biomass and abundance of taxa in salamander diets. Total macroinvertebrate biomass was generally higher in pools; however, the majority of salamander prey biomass was from riffle habitats, a trend that was stronger for D. quadramaculatus than for E. cirrigera. There was greater similarity in taxa comprising diet by abundance with the majority of prey items originating from pools. 5. The larval salamander species used similar prey FFGs but differed significantly in specific prey taxa. We hypothesise that species differences in diets were most likely a function of differences in larval size and microhabitat use. Consequently, the treatment of larval salamanders as a guild is probably inadequate for predicting the effect of larval salamander diversity on some stream processes, and species may differ in how they respond to factors affecting prey assemblages.

@article{wyderko_variable_2015,
	title = {Variable infection of stream salamanders in the southern {Appalachians} by the trematode {Metagonimoides} oregonensis (family: {Heterophyidae})},
	volume = {114},
	copyright = {All rights reserved},
	doi = {10.1007/s00436-015-4550-8},
	abstract = {Many factors contribute to parasites varying in host specificity and distribution among potential hosts. Metagonimoides oregonensis is a digenetic trematode that uses stream-dwelling plethodontid salamanders as second intermediate hosts in the Eastern US. We completed a field survey to identify which stream salamander species, at a regional level, are most likely to be important for transmission to raccoon definitive hosts. We surveyed six plethodontid species (N=289 salamanders) from 23 Appalachian headwater sites in North Carolina: Desmognathus quadramaculatus (n=69), Eurycea wilderae (n=160), Desmognathus ocoee (n =31), Desmognathus monticola (n =3), Eurycea guttolineata (n=7), and Gyrinophilus porphyriticus (n=19). We found infection in all species except D. monticola. Further analysis focused on comparing infection in the two most abundant species, D. quadramaculatus and E. wilderae.We found that D. quadramaculatus had significantly higher infection prevalence and intensity, probably due to a longer aquatic larval period and larger body sizes and thus greater cumulative exposure to the parasite.},
	number = {8},
	journal = {Parasitology Research},
	author = {Wyderko, J.A. and Benfield, E.F. and Maerz, J.C. and Cecala, K.C. and Belden, L.K.},
	year = {2015},
	keywords = {Elimia, Eurycea, Heterophyid, Pleth, [Desmognathus},
	pages = {3159--3165},
}

Many factors contribute to parasites varying in host specificity and distribution among potential hosts. Metagonimoides oregonensis is a digenetic trematode that uses stream-dwelling plethodontid salamanders as second intermediate hosts in the Eastern US. We completed a field survey to identify which stream salamander species, at a regional level, are most likely to be important for transmission to raccoon definitive hosts. We surveyed six plethodontid species (N=289 salamanders) from 23 Appalachian headwater sites in North Carolina: Desmognathus quadramaculatus (n=69), Eurycea wilderae (n=160), Desmognathus ocoee (n =31), Desmognathus monticola (n =3), Eurycea guttolineata (n=7), and Gyrinophilus porphyriticus (n=19). We found infection in all species except D. monticola. Further analysis focused on comparing infection in the two most abundant species, D. quadramaculatus and E. wilderae.We found that D. quadramaculatus had significantly higher infection prevalence and intensity, probably due to a longer aquatic larval period and larger body sizes and thus greater cumulative exposure to the parasite.

@article{grosse_effects_2015,
	title = {Effects of vegetation and artifical habitat management on the nesting success and sex ratios of {Carolina} diamondback terrapins ({Malaclemys} terrapin)},
	volume = {6},
	copyright = {All rights reserved},
	abstract = {It is often the case that multiple factors contribute to wildlife population declines such that management will require simultaneous, integrated interventions to stabilize and recover populations. Diamondback terrapins Malaclemys terrapin are a species of high conservation priority, and local populations can be threatened by multiple factors, including bycatch in commercial and recreational crab pots, vehicle strikes on coastal roads, nest depredation from subsidized and introduced predators, and terrestrial habitat alteration. Mitigation of just one of these factors will often be insufficient for recovering at-risk populations; thus, information to manage multiple threats is needed. We measured the effects of natural vegetation structure and constructed (artificial) nesting habitat on hatchling sex ratios and nest depredation for a declining terrapin population on Jekyll Island, Georgia. Nest temperatures were highest on constructed nesting mounds, intermediate in open grass areas, and coolest under the shrub-dominated hedgerows. Higher nest temperatures led to shorter incubation times for nests on mounds and open habitat, such that all surviving nests on nesting mounds and open areas produced female hatchlings. In contrast, surviving nests under hedge produced 85\% male hatchlings. Raccoon Procyon lotor predation rates of simulated (chicken egg) nests were highest on nesting mounds (95.3\%), followed by hedge (84.4\%) and open habitats (45.2\%). Our results demonstrate that vegetation management can positively affect both production of female hatchlings and nest survival. Artificial nest mounds were successful at producing female hatchlings, but we documented high predation of simulated (chicken egg) nests despite structures to exclude predators. Further modifications to nest boxes atop constructed nesting mounds are needed for these devices to effectively contribute to population management. We suggest the relatively low cost and maintenance associated with removing shrubs and trees can be a viable strategy to manage large areas of nesting habitat for the increased production of female turtles, and to reduce the impacts of subsidized predators.},
	journal = {Journal of Fish and Wildlife Management},
	author = {Grosse, Andrew M and Crawford, Brian A and Maerz, John C and Buhlmann, K A and Norton, Terry M and Kaylor, Michelle and Tuberville, Tracey D},
	year = {2015},
	pages = {19--28},
}

It is often the case that multiple factors contribute to wildlife population declines such that management will require simultaneous, integrated interventions to stabilize and recover populations. Diamondback terrapins Malaclemys terrapin are a species of high conservation priority, and local populations can be threatened by multiple factors, including bycatch in commercial and recreational crab pots, vehicle strikes on coastal roads, nest depredation from subsidized and introduced predators, and terrestrial habitat alteration. Mitigation of just one of these factors will often be insufficient for recovering at-risk populations; thus, information to manage multiple threats is needed. We measured the effects of natural vegetation structure and constructed (artificial) nesting habitat on hatchling sex ratios and nest depredation for a declining terrapin population on Jekyll Island, Georgia. Nest temperatures were highest on constructed nesting mounds, intermediate in open grass areas, and coolest under the shrub-dominated hedgerows. Higher nest temperatures led to shorter incubation times for nests on mounds and open habitat, such that all surviving nests on nesting mounds and open areas produced female hatchlings. In contrast, surviving nests under hedge produced 85% male hatchlings. Raccoon Procyon lotor predation rates of simulated (chicken egg) nests were highest on nesting mounds (95.3%), followed by hedge (84.4%) and open habitats (45.2%). Our results demonstrate that vegetation management can positively affect both production of female hatchlings and nest survival. Artificial nest mounds were successful at producing female hatchlings, but we documented high predation of simulated (chicken egg) nests despite structures to exclude predators. Further modifications to nest boxes atop constructed nesting mounds are needed for these devices to effectively contribute to population management. We suggest the relatively low cost and maintenance associated with removing shrubs and trees can be a viable strategy to manage large areas of nesting habitat for the increased production of female turtles, and to reduce the impacts of subsidized predators.

@article{kominoski_low--moderate_2015,
	title = {Low-to-moderate nitrogen and phosphorus concentrations accelerate microbially driven litter breakdown rates},
	volume = {25},
	copyright = {All rights reserved},
	abstract = {Particulate organic matter (POM) processing is an important driver of aquatic ecosystem productivity that is sensitive to nutrient enrichment and drives ecosystem carbon (C) loss. Although studies of single concentrations of nitrogen (N) or phosphorus (P) have shown effects at relatively low concentrations, responses of litter breakdown rates along gradients of low-to-moderate N and P concentrations are needed to establish likely interdependent effects of dual N and P enrichment on baseline activity in stream ecosystems. We established 25 combinations of dissolved inorganic N (DIN; 55–545 lg/L) and soluble reactive P (SRP; 4–86 lg/L) concentrations with corresponding N:P molar ratios of 2–127 in experimental stream channels. We excluded macroinvertebrates, focusing on microbially driven breakdown of maple (Acer rubrum L.) and rhododendron (Rhododendron maximum L.) leaf litter. Breakdown rates, k, per day (d 1) and per degree-day (dd 1), increased by up to 63 for maple and 123 for rhododendron over our N and P enrichment gradient compared to rates at low ambient N and P concentrations. The best models of k (d 1 and dd 1) included litter species identity and N and P concentrations; there was evidence for both additive and interactive effects of N and P. Models explaining variation in k dd 1 were supported by N and P for both maple and rhododendron (R2adj 1⁄4 0.67 and 0.33, respectively). Residuals in the relationship between k dd 1 and N concentration were largely explained by P, but residuals for k dd 1 and P concentration were less adequately explained by N. Breakdown rates were more closely related to nutrient concentrations than variables associated with measurements of two mechanistic parameters associated with C loss (fungal biomass and microbial respiration rate). We also determined the effects of nutrient addition on litter C:nutrient stoichiometry and found reductions in litter C:N and C:P along our experimental nutrient gradient. Our results indicate that microbially driven litter processing rates increase across low-to-moderate nutrient gradients that are now common throughout human-modified landscapes.},
	number = {3},
	journal = {Ecological Applications},
	author = {Kominoski, J S and Rosemond, A D and Benstead, J P and Gulis, Vladislav and Maerz, John C and Manning, David W P},
	year = {2015},
	pages = {856--865},
}

Particulate organic matter (POM) processing is an important driver of aquatic ecosystem productivity that is sensitive to nutrient enrichment and drives ecosystem carbon (C) loss. Although studies of single concentrations of nitrogen (N) or phosphorus (P) have shown effects at relatively low concentrations, responses of litter breakdown rates along gradients of low-to-moderate N and P concentrations are needed to establish likely interdependent effects of dual N and P enrichment on baseline activity in stream ecosystems. We established 25 combinations of dissolved inorganic N (DIN; 55–545 lg/L) and soluble reactive P (SRP; 4–86 lg/L) concentrations with corresponding N:P molar ratios of 2–127 in experimental stream channels. We excluded macroinvertebrates, focusing on microbially driven breakdown of maple (Acer rubrum L.) and rhododendron (Rhododendron maximum L.) leaf litter. Breakdown rates, k, per day (d 1) and per degree-day (dd 1), increased by up to 63 for maple and 123 for rhododendron over our N and P enrichment gradient compared to rates at low ambient N and P concentrations. The best models of k (d 1 and dd 1) included litter species identity and N and P concentrations; there was evidence for both additive and interactive effects of N and P. Models explaining variation in k dd 1 were supported by N and P for both maple and rhododendron (R2adj 1⁄4 0.67 and 0.33, respectively). Residuals in the relationship between k dd 1 and N concentration were largely explained by P, but residuals for k dd 1 and P concentration were less adequately explained by N. Breakdown rates were more closely related to nutrient concentrations than variables associated with measurements of two mechanistic parameters associated with C loss (fungal biomass and microbial respiration rate). We also determined the effects of nutrient addition on litter C:nutrient stoichiometry and found reductions in litter C:N and C:P along our experimental nutrient gradient. Our results indicate that microbially driven litter processing rates increase across low-to-moderate nutrient gradients that are now common throughout human-modified landscapes.

@article{lee_writing_2015,
	title = {Writing stories in the sciences},
	volume = {44},
	copyright = {All rights reserved},
	abstract = {Writing stories is advocated as an excellent means of learning the process of science; however, little is understood about students’ experiences of engaging in story writing in postsecondary science courses. Our study was designed to improve the practice of using stories in the sciences by examining students’ lived experience through interviews, surveys, and observations. Students perceived the learning goal as public outreach and networking with the science community rather than learning the process of science. They reported dif culty blending science into narratives and requested structured guidance throughout the process. Without such guidance, some found it dif cult to engage in this autonomous, nontraditional assignment. We integrated students’ suggestions into the next implementation while keeping some elements open-ended. Narrative writing holds potential for gaining more hands-on knowledge of the processes of science and communicating scienti c  ndings to a general audience, as well as enhancing self-knowledge about academic interests.},
	number = {4},
	journal = {Journal of College Science Teaching},
	author = {Lee, Eunbae and Maerz, John C},
	year = {2015},
	pages = {36--45},
}

Writing stories is advocated as an excellent means of learning the process of science; however, little is understood about students’ experiences of engaging in story writing in postsecondary science courses. Our study was designed to improve the practice of using stories in the sciences by examining students’ lived experience through interviews, surveys, and observations. Students perceived the learning goal as public outreach and networking with the science community rather than learning the process of science. They reported dif culty blending science into narratives and requested structured guidance throughout the process. Without such guidance, some found it dif cult to engage in this autonomous, nontraditional assignment. We integrated students’ suggestions into the next implementation while keeping some elements open-ended. Narrative writing holds potential for gaining more hands-on knowledge of the processes of science and communicating scienti c ndings to a general audience, as well as enhancing self-knowledge about academic interests.

@article{mckee_processes_2015,
	title = {Processes that regulate patterns of species and genetic diversity},
	volume = {10},
	copyright = {All rights reserved},
	url = {http://www.esa.org/tiee/vol/v10/experiments/mckee/pdf/mckee.pdf},
	abstract = {During a single lab period, students simulate colonization and drift in artificial communities to understand how these processes affect distributions of biodiversity in small versus large communities with varying degrees of isolation. Plastic bins represent islands, and are situated to represent different degrees of isolation. Ziploc bags of candy represent individuals in the communities and different candies inside the bags represent the genetic composition of the individuals. Students simulate colonization and drift in communities by tossing, replicating, and removing individuals from their communities. Students record which individuals and candies are removed from and added to their communities over time, graph their data, and discuss results.},
	journal = {Teaching Issues and Experiments in Ecology},
	author = {McKee, Anna M and Green, Gary T and Maerz, John C},
	year = {2015},
	note = {Edition: January 20},
	pages = {1--44},
}

During a single lab period, students simulate colonization and drift in artificial communities to understand how these processes affect distributions of biodiversity in small versus large communities with varying degrees of isolation. Plastic bins represent islands, and are situated to represent different degrees of isolation. Ziploc bags of candy represent individuals in the communities and different candies inside the bags represent the genetic composition of the individuals. Students simulate colonization and drift in communities by tossing, replicating, and removing individuals from their communities. Students record which individuals and candies are removed from and added to their communities over time, graph their data, and discuss results.

@article{maerz_detecting_2015,
	title = {Detecting enigmatic declines of a once common salamander in the {Coastal} {Plain} of {Georgia}},
	volume = {14},
	copyright = {All rights reserved},
	abstract = {For amphibian species suspected of undergoing enigmatic declines, it is impor- tant to determine the effort required to con dently establish species absence. Desmognathus auriculatus (Southern Dusky Salamander) has purportedly gone from being quite common throughout the southeastern US Coastal Plain to now being enigmatically rare. We used repeated standardized surveys of 5 historically occupied streams and their adjacent riparian zones between 2007 and 2010 to estimate detection rate of Southern Dusky Salamanders. We detected Southern Dusky Salamanders at 3 of 5 historic sites. Mean detection rate across streams known to be occupied at least once during the study was moderately low (mean ± 1 SE = 0.20 ± 0.12 for a double-sampled 50-m survey), improved at 2 sites with increasing time since drought, and varied among streams. For comparison, we evaluated detection rates of several other stream salamanders and found those rates to range from 0.37 (± 0.07) for Eurycea quadridigitata (Dwarf Salamander) to 0.08 (± 0.01) for Siren intermedia (Lesser Siren). Based on mark–recapture along a 200-m section of stream and the associated ripar- ian habitat at the site where Southern Dusky Salamanders were most often detected, we estimated 43 (± 15) and 97 (± 161) individuals to be present February–May 2009 and Oc- tober 2009–May 2010, respectively. Despite abundant adults, Southern Dusky Salamanders were the only species that we failed to detect as larvae; however, we observed many newly metamorphosed Southern Dusky Salamanders—usually under logs with saturated soil and often near entrances to cray sh burrows. Our results generally support the characterizations of Southern Dusky Salamanders as having become enigmatically uncommon. Because land- cover change in the study area has been minimal, we suspect habitat damage from Sus scrofa (Feral Pig) may be responsible for the variation in Southern Dusky Salamander presence and abundance among sites. Because of the low detectability of Southern Dusky Salaman- ders, future work to identify factors driving Southern Dusky Salamander distribution and abundance will require intensive sampling at sites to provide robust estimates of occupancy or population size.},
	journal = {Southeastern Naturalist},
	author = {Maerz, John C and Barrett, R Kyle and Cecala, Kristen K and DeVore, Jayna L},
	year = {2015},
	pages = {771--784},
}

For amphibian species suspected of undergoing enigmatic declines, it is impor- tant to determine the effort required to con dently establish species absence. Desmognathus auriculatus (Southern Dusky Salamander) has purportedly gone from being quite common throughout the southeastern US Coastal Plain to now being enigmatically rare. We used repeated standardized surveys of 5 historically occupied streams and their adjacent riparian zones between 2007 and 2010 to estimate detection rate of Southern Dusky Salamanders. We detected Southern Dusky Salamanders at 3 of 5 historic sites. Mean detection rate across streams known to be occupied at least once during the study was moderately low (mean ± 1 SE = 0.20 ± 0.12 for a double-sampled 50-m survey), improved at 2 sites with increasing time since drought, and varied among streams. For comparison, we evaluated detection rates of several other stream salamanders and found those rates to range from 0.37 (± 0.07) for Eurycea quadridigitata (Dwarf Salamander) to 0.08 (± 0.01) for Siren intermedia (Lesser Siren). Based on mark–recapture along a 200-m section of stream and the associated ripar- ian habitat at the site where Southern Dusky Salamanders were most often detected, we estimated 43 (± 15) and 97 (± 161) individuals to be present February–May 2009 and Oc- tober 2009–May 2010, respectively. Despite abundant adults, Southern Dusky Salamanders were the only species that we failed to detect as larvae; however, we observed many newly metamorphosed Southern Dusky Salamanders—usually under logs with saturated soil and often near entrances to cray sh burrows. Our results generally support the characterizations of Southern Dusky Salamanders as having become enigmatically uncommon. Because land- cover change in the study area has been minimal, we suspect habitat damage from Sus scrofa (Feral Pig) may be responsible for the variation in Southern Dusky Salamander presence and abundance among sites. Because of the low detectability of Southern Dusky Salaman- ders, future work to identify factors driving Southern Dusky Salamander distribution and abundance will require intensive sampling at sites to provide robust estimates of occupancy or population size.

@article{crawford_hot_2014,
	title = {Hot spots and hot moments of diamondback terrapin road-crossing activity},
	volume = {51},
	copyright = {All rights reserved},
	doi = {10.1111/1365-2664.12195},
	abstract = {Summary: Road mortality is a major component of human impacts on wildlife populations, and the pervasiveness of roads on the landscape presents a substantial challenge for managing those impacts. The feasibility of methods to reduce road mortality depends on the degree to which this threat is spatially or temporally concentrated, which can be based on habitat, human activities or species' ecology. Diamondback terrapins Malaclemys terrapin are a species of conservation concern across their range, and road mortality is a major threat contributing to local population declines. We used intensive road surveys of the 8?7-km Downing-Musgrove Causeway to Jekyll Island, Georgia, USA, over 2 years to determine whether road activity and mortality was diffused or concentrated spatially (hot spots) or temporally (hot moments) in order to guide efficient management. In 2009 and 2010, we documented 636 terrapin crossings that were temporally and spatially condensed. Temporally, there was a 70-80\% chance of a terrapin occurring on the road within a 3-h period around the diurnal high tide and within the first 30 days of the ?75 day nesting season. Over the two nesting seasons, 52\% of terrapin occurrences on the road occurred within the 3-h period around high tide. Spatially, 30\% of terrapins were observed crossing in three hot spots that composed less than 10\% of the length of the entire causeway, and the percentage of unvegetated high marsh was negatively associated with the number of terrapins that occurred on a section of road. Synthesis and applications. Our results demonstrate that hot spots and hot moments can be identified for species at finer scales than those found by other studies and are related, strongly or weakly, to specific temporal processes or habitat features. We found patterns of road mortality, like most threats, can be diffused or concentrated; therefore, complementary management tools that focus on hot spots or moments and also address the more diffused component of road mortality will be required to reduce this threat for at-risk wildlife. Our results demonstrate that hot spots and hot moments can be identified for species at finer scales than those found by other studies and are related, strongly or weakly, to specific temporal processes or habitat features. We found patterns of road mortality, like most threats, can be diffused or concentrated; therefore, complementary management tools that focus on hot spots or moments and also address the more diffused component of road mortality will be required to reduce this threat for at-risk wildlife. ? 2013 British Ecological Society.},
	number = {2},
	journal = {Journal of Applied Ecology},
	author = {Crawford, B.A. and Maerz, J.C. and Nibbelink, N.P. and Buhlmann, K.A. and Norton, T.M. and Albeke, S.E.},
	year = {2014},
	keywords = {Georgia, Hot moment, Hot sp, [Diamondback terrapin},
	pages = {367--375},
}

Summary: Road mortality is a major component of human impacts on wildlife populations, and the pervasiveness of roads on the landscape presents a substantial challenge for managing those impacts. The feasibility of methods to reduce road mortality depends on the degree to which this threat is spatially or temporally concentrated, which can be based on habitat, human activities or species' ecology. Diamondback terrapins Malaclemys terrapin are a species of conservation concern across their range, and road mortality is a major threat contributing to local population declines. We used intensive road surveys of the 8?7-km Downing-Musgrove Causeway to Jekyll Island, Georgia, USA, over 2 years to determine whether road activity and mortality was diffused or concentrated spatially (hot spots) or temporally (hot moments) in order to guide efficient management. In 2009 and 2010, we documented 636 terrapin crossings that were temporally and spatially condensed. Temporally, there was a 70-80% chance of a terrapin occurring on the road within a 3-h period around the diurnal high tide and within the first 30 days of the ?75 day nesting season. Over the two nesting seasons, 52% of terrapin occurrences on the road occurred within the 3-h period around high tide. Spatially, 30% of terrapins were observed crossing in three hot spots that composed less than 10% of the length of the entire causeway, and the percentage of unvegetated high marsh was negatively associated with the number of terrapins that occurred on a section of road. Synthesis and applications. Our results demonstrate that hot spots and hot moments can be identified for species at finer scales than those found by other studies and are related, strongly or weakly, to specific temporal processes or habitat features. We found patterns of road mortality, like most threats, can be diffused or concentrated; therefore, complementary management tools that focus on hot spots or moments and also address the more diffused component of road mortality will be required to reduce this threat for at-risk wildlife. Our results demonstrate that hot spots and hot moments can be identified for species at finer scales than those found by other studies and are related, strongly or weakly, to specific temporal processes or habitat features. We found patterns of road mortality, like most threats, can be diffused or concentrated; therefore, complementary management tools that focus on hot spots or moments and also address the more diffused component of road mortality will be required to reduce this threat for at-risk wildlife. ? 2013 British Ecological Society.

@article{devore_grass_2014,
	title = {Grass invasion increases top-down pressure on an amphibian via structurally mediated effects on an intraguild predator},
	volume = {95},
	copyright = {All rights reserved},
	doi = {10.1890/13-1715.1},
	abstract = {Plants serve as both basal resources and ecosystem engineers, so plant invasion may exert trophic influences on consumers both via bottom-up processes and by altering the environmental context in which trophic interactions occur. To determine how these mechanisms affect a native predator we used a mark-recapture study in eight pairs of 58- m2 field enclosures to measure the influence of Japanese stilt grass invasion on 3200 recently metamorphosed American toads. Toad survivorship was lower in invaded habitats despite abiotic effects that favor amphibians. Prey densities were also lower in invaded habitats, but growth was unaffected. Frequent spider predation events in invaded habitats led us to use factorial field cage manipulations of stilt grass and lycosid spiders to determine if invasion increases predation rates. Spiders persisted at higher densities in the presence of stilt grass, and toad survival was lowest in cages with both grass and spiders. Invasion alone did not significantly reduce toad survival. Our results demonstrate that despite prey reductions and abiotic effects, it is increased spider persistence that reduces toad survival in invaded habitats. Invasion therefore affects resident forest floor consumers by modifying trophic interactions between native species, causing structurally mediated reductions in intraguild predation rates among spiders, with cascading implications for toad survival. ? 2014 by the Ecological Society of America.},
	number = {7},
	journal = {Ecology},
	author = {Devore, J.L. and Maerz, J.C.},
	year = {2014},
	keywords = {Ecosystem Engineer, Food Web, [Anaxyrus Americanus},
	pages = {1724--1730},
}

Plants serve as both basal resources and ecosystem engineers, so plant invasion may exert trophic influences on consumers both via bottom-up processes and by altering the environmental context in which trophic interactions occur. To determine how these mechanisms affect a native predator we used a mark-recapture study in eight pairs of 58- m2 field enclosures to measure the influence of Japanese stilt grass invasion on 3200 recently metamorphosed American toads. Toad survivorship was lower in invaded habitats despite abiotic effects that favor amphibians. Prey densities were also lower in invaded habitats, but growth was unaffected. Frequent spider predation events in invaded habitats led us to use factorial field cage manipulations of stilt grass and lycosid spiders to determine if invasion increases predation rates. Spiders persisted at higher densities in the presence of stilt grass, and toad survival was lowest in cages with both grass and spiders. Invasion alone did not significantly reduce toad survival. Our results demonstrate that despite prey reductions and abiotic effects, it is increased spider persistence that reduces toad survival in invaded habitats. Invasion therefore affects resident forest floor consumers by modifying trophic interactions between native species, causing structurally mediated reductions in intraguild predation rates among spiders, with cascading implications for toad survival. ? 2014 by the Ecological Society of America.

@article{gilbert_exploring_2014,
	title = {Exploring carbon flow through the root channel in a temperate forest soil food web},
	volume = {76},
	copyright = {All rights reserved},
	doi = {10.1016/j.soilbio.2014.05.005},
	abstract = {Soil food webs play an important role in forest ecosystem functions that may be sensitive to global environmental change. We traced a pulse of 13C from the root systems of young sugar maple stands through the soil food web to explore energy flow from roots to soil heterotrophs. Invasive earthworms (Lumbricidae) were the most highly-enriched taxa sampled, indicating that they were consuming significant quantities of live fine roots and mycorrhizae and assimilating significant amounts of root-derived C. Another invasive invertebrate, a weevil (Barypeithes pellucidus) also appeared to consume significant amounts of roots or root-derived C. High isotope enrichment in ants (Formicidae) may reflect their feeding on phloem-sucking coccids in soil. All the predators collected from the litter layer also exhibited high isotope enrichment, including the salamander Plethodon cinereus. Moreover, in the absence of invasive earthworms all the taxa of animals collected from surface soil were similarly highly-enriched in root-derived isotopes. The apparent importance of the root channel in supplying energy to the soil food web suggests that forest ecosystem functions could be highly sensitive to global changes that alter proportional tree C allocation belowground. ? 2014 Elsevier Ltd.},
	journal = {Soil Biology and Biochemistry},
	author = {Gilbert, Kadeem J. and Fahey, Timothy J. and Maerz, John C. and Sherman, Ruth E. and Bohlen, Patrick J. and Dombroskie, J. J. and Groffman, Peter M. and Yavitt, Joseph B.},
	year = {2014},
	keywords = {Carbon, Earthworms, Energy flow, Invasive s, [Ants},
	pages = {45--52},
}

Soil food webs play an important role in forest ecosystem functions that may be sensitive to global environmental change. We traced a pulse of 13C from the root systems of young sugar maple stands through the soil food web to explore energy flow from roots to soil heterotrophs. Invasive earthworms (Lumbricidae) were the most highly-enriched taxa sampled, indicating that they were consuming significant quantities of live fine roots and mycorrhizae and assimilating significant amounts of root-derived C. Another invasive invertebrate, a weevil (Barypeithes pellucidus) also appeared to consume significant amounts of roots or root-derived C. High isotope enrichment in ants (Formicidae) may reflect their feeding on phloem-sucking coccids in soil. All the predators collected from the litter layer also exhibited high isotope enrichment, including the salamander Plethodon cinereus. Moreover, in the absence of invasive earthworms all the taxa of animals collected from surface soil were similarly highly-enriched in root-derived isotopes. The apparent importance of the root channel in supplying energy to the soil food web suggests that forest ecosystem functions could be highly sensitive to global changes that alter proportional tree C allocation belowground. ? 2014 Elsevier Ltd.

@article{mcentire_eurycea_2014,
	title = {Eurycea cirrigera ({Southern} two-lined salamander). {Paedomorphosis}},
	volume = {45},
	copyright = {All rights reserved},
	abstract = {On 19 January 2014, we discovered what appeared to be a large (SVL = 38 mm; total length = 75 mm), but typically marked, E. cirrigera larva in a small, impounded stream in Athens, Clarke Co., Georgia, USA (33.8909°N, 83.3624°W; datum: WGS84). However, the larva was visibly gravid; developing ova could be seen through her transparent ventral skin. The salamander was euthanized and dissected and found to have 27 distinct ova in her right oviduct and 24 ova in her left oviduct. This falls within the typical clutch size of the species (Petranka 1998. Salamanders of the United States and Canada. Smithsonian Institution Press, Washington, DC. 587 pp.). Tissues from the female and her eggs were preserved in 95\% EtOH, and deposited as GMNH 50696. To the best of our knowledge, the only other report of neoteny in E. cirrigera was from Mount (1975. The Amphibians and Reptiles of Alabama. University of Alabama Press. 268 pp.), who described it as “not uncommon” in Alabama. Rose and Bush (1963. Tulane Stud. Zool. 10:121–128) describe several male and female E. aquatica with well-developed testes and ova, but report that all had typical adult coloration and classify their status as representative of “precocious reproductive development and not true neoteny”. No other published accounts of neoteny in the Eurycea bislineata complex exist. We revisited the site of collection and nearby streams on 26 January 2014 and collected 53 E. cirrigera larvae, but all were smaller than the gravid female and none had visible developing ova. Metamorphosed adult female E. cirrigera were gravid during this time. Additionally, we examined 74 E. cirrigera larvae of at least 30 mm SVL in the GMNH collection, and none of them appeared to be gravid females.},
	number = {3},
	journal = {Herpetological Review},
	author = {McEntire, Kira D and Pierson, Todd W and Maerz, John C},
	year = {2014},
	pages = {473--473},
}

On 19 January 2014, we discovered what appeared to be a large (SVL = 38 mm; total length = 75 mm), but typically marked, E. cirrigera larva in a small, impounded stream in Athens, Clarke Co., Georgia, USA (33.8909°N, 83.3624°W; datum: WGS84). However, the larva was visibly gravid; developing ova could be seen through her transparent ventral skin. The salamander was euthanized and dissected and found to have 27 distinct ova in her right oviduct and 24 ova in her left oviduct. This falls within the typical clutch size of the species (Petranka 1998. Salamanders of the United States and Canada. Smithsonian Institution Press, Washington, DC. 587 pp.). Tissues from the female and her eggs were preserved in 95% EtOH, and deposited as GMNH 50696. To the best of our knowledge, the only other report of neoteny in E. cirrigera was from Mount (1975. The Amphibians and Reptiles of Alabama. University of Alabama Press. 268 pp.), who described it as “not uncommon” in Alabama. Rose and Bush (1963. Tulane Stud. Zool. 10:121–128) describe several male and female E. aquatica with well-developed testes and ova, but report that all had typical adult coloration and classify their status as representative of “precocious reproductive development and not true neoteny”. No other published accounts of neoteny in the Eurycea bislineata complex exist. We revisited the site of collection and nearby streams on 26 January 2014 and collected 53 E. cirrigera larvae, but all were smaller than the gravid female and none had visible developing ova. Metamorphosed adult female E. cirrigera were gravid during this time. Additionally, we examined 74 E. cirrigera larvae of at least 30 mm SVL in the GMNH collection, and none of them appeared to be gravid females.

@article{mercurio_experimental_2014,
	title = {Experimental feeding of {Hydrilla} verticillata colonized by stigonematales cyanobacteria induces vacuolar myelinopathy in painted turtles ({Chrysemys} picta)},
	volume = {9},
	copyright = {All rights reserved},
	doi = {10.1371/journal.pone.0093295},
	abstract = {Vacuolar myelinopathy (VM) is a neurologic disease primarily found in birds that occurs when wildlife ingest submerged aquatic vegetation colonized by an uncharacterized toxin-producing cyanobacterium (hereafter "UCB" for "uncharacterized cyanobacterium"). Turtles are among the closest extant relatives of birds and many species directly and/or indirectly consume aquatic vegetation. However, it is unknown whether turtles can develop VM. We conducted a feeding trial to determine whether painted turtles (Chrysemys picta) would develop VM after feeding on Hydrilla (Hydrilla verticillata), colonized by the UCB (Hydrilla is the most common "host" of UCB). We hypothesized turtles fed Hydrilla colonized by the UCB would exhibit neurologic impairment and vacuolation of nervous tissues, whereas turtles fed Hydrilla free of the UCB would not. The ability of Hydrilla colonized by the UCB to cause VM (hereafter, "toxicity") was verified by feeding it to domestic chickens (Gallus gallus domesticus) or necropsy of field collected American coots (Fulica americana) captured at the site of Hydrilla collections. We randomly assigned ten wild-caught turtles into toxic or non-toxic Hydrilla feeding groups and delivered the diets for up to 97 days. Between days 82 and 89, all turtles fed toxic Hydrilla displayed physical and/or neurologic impairment. Histologic examination of the brain and spinal cord revealed vacuolations in all treatment turtles. None of the control turtles exhibited neurologic impairment or had detectable brain or spinal cord vacuolations. This is the first evidence that freshwater turtles can become neurologically impaired and develop vacuolations after consuming toxic Hydrilla colonized with the UCB. The southeastern United States, where outbreaks of VM occur regularly and where vegetation colonized by the UCB is common, is also a global hotspot of freshwater turtle diversity. Our results suggest that further investigations into the effect of the putative UCB toxin on wild turtles in situ are warranted. ? 2014 Mercurio et al.},
	number = {4},
	journal = {PLoS ONE},
	author = {Mercurio, A.D. and Hernandez, S.M. and Maerz, J.C. and Yabsley, M.J. and Ellis, A.E. and Coleman, A.L. and Shelnutt, L.M. and Fischer, J.R. and Wilde, S.B.},
	year = {2014},
	pages = {e93295},
}

Vacuolar myelinopathy (VM) is a neurologic disease primarily found in birds that occurs when wildlife ingest submerged aquatic vegetation colonized by an uncharacterized toxin-producing cyanobacterium (hereafter "UCB" for "uncharacterized cyanobacterium"). Turtles are among the closest extant relatives of birds and many species directly and/or indirectly consume aquatic vegetation. However, it is unknown whether turtles can develop VM. We conducted a feeding trial to determine whether painted turtles (Chrysemys picta) would develop VM after feeding on Hydrilla (Hydrilla verticillata), colonized by the UCB (Hydrilla is the most common "host" of UCB). We hypothesized turtles fed Hydrilla colonized by the UCB would exhibit neurologic impairment and vacuolation of nervous tissues, whereas turtles fed Hydrilla free of the UCB would not. The ability of Hydrilla colonized by the UCB to cause VM (hereafter, "toxicity") was verified by feeding it to domestic chickens (Gallus gallus domesticus) or necropsy of field collected American coots (Fulica americana) captured at the site of Hydrilla collections. We randomly assigned ten wild-caught turtles into toxic or non-toxic Hydrilla feeding groups and delivered the diets for up to 97 days. Between days 82 and 89, all turtles fed toxic Hydrilla displayed physical and/or neurologic impairment. Histologic examination of the brain and spinal cord revealed vacuolations in all treatment turtles. None of the control turtles exhibited neurologic impairment or had detectable brain or spinal cord vacuolations. This is the first evidence that freshwater turtles can become neurologically impaired and develop vacuolations after consuming toxic Hydrilla colonized with the UCB. The southeastern United States, where outbreaks of VM occur regularly and where vegetation colonized by the UCB is common, is also a global hotspot of freshwater turtle diversity. Our results suggest that further investigations into the effect of the putative UCB toxin on wild turtles in situ are warranted. ? 2014 Mercurio et al.

@article{barrett_identifying_2014,
	title = {Identifying {Priority} {Species} and {Conservation} {Opportunities} {Under} {Future} {Climate} {Scenarios}: {Amphibians} in a {Biodiversity} {Hotspot}},
	volume = {5},
	copyright = {All rights reserved},
	doi = {10.3996/022014-JFWM-015},
	abstract = {Climate change is driving shifts in the distribution of plants and animals, and prioritizing management actions for such shifts is a necessary but technically difficult challenge. We worked with state agencies in the southeastern United States to identify high-priority amphibian species, to model the vulnerabilities of those species to regional climate change, and to identify long-term climatic refugia within the context of existing conservation lands. Directly interfacing with state natural resource experts ensured that 1) species prioritization schemes extend beyond political boundaries and 2) our models resulted in conservation-relevant applications. We used a correlative model to project midcentury distributions of suitable climate for priority species and to evaluate each species' vulnerability to climate change. Using spatially explicit projected climate distributions, we ranked existing protected areas relative to their ability to provide climatic refugia for priority species in 2050. We identified 21 species as regional high-priority species. Fifteen of the 21 species are forecast to lose more than 85\% of their climatically suitable habitat. Regions in the Appalachian Mountains, the Florida Panhandle, and the north-central region of Alabama are projected to lose the most climatic habitat for priority amphibian species. We identified many existing protected areas as midcentury climatic refugia in the Appalachians; however, our projections indicated refugia in the Southeast Coastal Plain to be exceedingly scarce. Although the topographic relief present in the Appalachians appears to provide future conservation opportunities via climatic refugia, the Coastal Plain affords fewer such opportunities and conservation of amphibians in that region is likely to be more challenging. The approach outlined here could be applied across a broad range of taxa and regions.},
	number = {2},
	journal = {Journal of Fish and Wildlife Management},
	author = {Barrett, Kyle and Nibbelink, Nathan P and Maerz, John C},
	year = {2014},
	keywords = {Appalachian Mountains, Coastal Plain, climatic niche, frog, salamander},
	pages = {282--297},
}

Climate change is driving shifts in the distribution of plants and animals, and prioritizing management actions for such shifts is a necessary but technically difficult challenge. We worked with state agencies in the southeastern United States to identify high-priority amphibian species, to model the vulnerabilities of those species to regional climate change, and to identify long-term climatic refugia within the context of existing conservation lands. Directly interfacing with state natural resource experts ensured that 1) species prioritization schemes extend beyond political boundaries and 2) our models resulted in conservation-relevant applications. We used a correlative model to project midcentury distributions of suitable climate for priority species and to evaluate each species' vulnerability to climate change. Using spatially explicit projected climate distributions, we ranked existing protected areas relative to their ability to provide climatic refugia for priority species in 2050. We identified 21 species as regional high-priority species. Fifteen of the 21 species are forecast to lose more than 85% of their climatically suitable habitat. Regions in the Appalachian Mountains, the Florida Panhandle, and the north-central region of Alabama are projected to lose the most climatic habitat for priority amphibian species. We identified many existing protected areas as midcentury climatic refugia in the Appalachians; however, our projections indicated refugia in the Southeast Coastal Plain to be exceedingly scarce. Although the topographic relief present in the Appalachians appears to provide future conservation opportunities via climatic refugia, the Coastal Plain affords fewer such opportunities and conservation of amphibians in that region is likely to be more challenging. The approach outlined here could be applied across a broad range of taxa and regions.

@article{cecala_riparian_2014,
	title = {Riparian disturbance restricts in-stream movement of salamanders},
	volume = {59},
	copyright = {All rights reserved},
	doi = {10.1111/fwb.12439},
	abstract = {Long-term population persistence or population rescue require dispersal from other source populations. Barriers to movement can effectively fragment and isolate populations, reducing persistence and recolonisation. For stream organisms that depend heavily on movement within dendritic networks, research is needed to identify and estimate the effects of such barriers on connectivity. We used capture–mark–recapture of displaced larval and adult salamanders to estimate return rates across gaps (length 13–85 m) in the riparian canopy and thus to assess the fragmentation of salamander populations within otherwise fully forested catchments. Relative to salamanders in fully forested reaches, displaced salamanders were 86\% less likely to return to their capture location when required to cross gaps in the canopy as short as 13 m, and the likelihood of return declined with increasing gap length. The effects of gaps on return rates were consistent among life stages and for up- and downstream movement. Our study suggests that riparian disturbance can reduce permeability to salamanders, even in the absence of additional land-use change. Because anthropogenic features, such as roads and powerlines, frequently cross small streams, the accumulation of apparently small land-cover changes has the potential to reduce continuous populations to small fragments with limited connectivity.},
	number = {11},
	journal = {Freshwater Biology},
	author = {Cecala, Kristen K. and Lowe, Winsor H. and Maerz, John C.},
	year = {2014},
	keywords = {Behaviour, Connectivity, Dispersal, Fragmentation, Phototaxis},
	pages = {2354--2364},
}

Long-term population persistence or population rescue require dispersal from other source populations. Barriers to movement can effectively fragment and isolate populations, reducing persistence and recolonisation. For stream organisms that depend heavily on movement within dendritic networks, research is needed to identify and estimate the effects of such barriers on connectivity. We used capture–mark–recapture of displaced larval and adult salamanders to estimate return rates across gaps (length 13–85 m) in the riparian canopy and thus to assess the fragmentation of salamander populations within otherwise fully forested catchments. Relative to salamanders in fully forested reaches, displaced salamanders were 86% less likely to return to their capture location when required to cross gaps in the canopy as short as 13 m, and the likelihood of return declined with increasing gap length. The effects of gaps on return rates were consistent among life stages and for up- and downstream movement. Our study suggests that riparian disturbance can reduce permeability to salamanders, even in the absence of additional land-use change. Because anthropogenic features, such as roads and powerlines, frequently cross small streams, the accumulation of apparently small land-cover changes has the potential to reduce continuous populations to small fragments with limited connectivity.

@article{fahey_earthworm_2013,
	title = {Earthworm effects on the incorporation of litter {C} and {N} into soil organic matter in a sugar maple forest},
	volume = {23},
	copyright = {All rights reserved},
	doi = {10.1890/12-1760.1},
	abstract = {To examine the mechanisms of earthworm effects on forest soil C and N, we double-labeled leaf litter with 13C and 15N, applied it to sugar maple forest plots with and without earthworms, and traced isotopes into soil pools. The experimental design included forest plots with different earthworm community composition (dominated by Lumbricus terrestris or L. rubellus). Soil carbon pools were 37\% lower in earthworm-invaded plots largely because of the elimination of the forest floor horizons, and mineral soil C:N was lower in earthworm plots despite the mixing of high C:N organic matter into soil by earthworms. Litter disappearance over the first winter-spring was highest in the L. terrestris (T) plots, but during the warm season, rapid loss of litter was observed in both L. rubellus (R) and T plots. After two years, 22.0\% ? 5.4\% of 13C released from litter was recovered in soil with no significant differences among plots. Total recovery of added 13C (decaying litter plus soil) was much higher in no-worm (NW) plots (61-68\%) than in R and T plots (20-29\%) as much of the litter remained in the former whereas it had disappeared in the latter. Much higher percentage recovery of 15N than 13C was observed, with significantly lower values for T than R and NW plots. Higher overwinter earthworm activity in T plots contributed to lower soil N recovery. In earthworm-invaded plots isotope enrichment was highest in macroaggregates and microaggregates whereas in NW plots silt plus clay fractions were most enriched. The net effect of litter mixing and priming of recalcitrant soil organic matter (SOM), stabilization of SOM in soil aggregates, and alteration of the soil microbial community by earthworm activity results in loss of SOM and lowering of the C:N ratio. We suggest that earthworm stoichiometry plays a fundamental role in regulating C and N dynamics of forest SOM. ? 2013 by the Ecological Society of America.},
	number = {5},
	journal = {Ecological Applications},
	author = {Fahey, Timothy J. and Yavitt, Joseph B. and Sherman, Ruth E. and Maerz, John C. and Groffman, Peter M. and Fisk, Melany C. and Bohlen, Patrick J.},
	year = {2013},
	keywords = {C:N ratio, Decomposition, Litter, Lumb, [Aggregate},
	pages = {1185--1201},
}

To examine the mechanisms of earthworm effects on forest soil C and N, we double-labeled leaf litter with 13C and 15N, applied it to sugar maple forest plots with and without earthworms, and traced isotopes into soil pools. The experimental design included forest plots with different earthworm community composition (dominated by Lumbricus terrestris or L. rubellus). Soil carbon pools were 37% lower in earthworm-invaded plots largely because of the elimination of the forest floor horizons, and mineral soil C:N was lower in earthworm plots despite the mixing of high C:N organic matter into soil by earthworms. Litter disappearance over the first winter-spring was highest in the L. terrestris (T) plots, but during the warm season, rapid loss of litter was observed in both L. rubellus (R) and T plots. After two years, 22.0% ? 5.4% of 13C released from litter was recovered in soil with no significant differences among plots. Total recovery of added 13C (decaying litter plus soil) was much higher in no-worm (NW) plots (61-68%) than in R and T plots (20-29%) as much of the litter remained in the former whereas it had disappeared in the latter. Much higher percentage recovery of 15N than 13C was observed, with significantly lower values for T than R and NW plots. Higher overwinter earthworm activity in T plots contributed to lower soil N recovery. In earthworm-invaded plots isotope enrichment was highest in macroaggregates and microaggregates whereas in NW plots silt plus clay fractions were most enriched. The net effect of litter mixing and priming of recalcitrant soil organic matter (SOM), stabilization of SOM in soil aggregates, and alteration of the soil microbial community by earthworm activity results in loss of SOM and lowering of the C:N ratio. We suggest that earthworm stoichiometry plays a fundamental role in regulating C and N dynamics of forest SOM. ? 2013 by the Ecological Society of America.

@article{fahey_earthworms_2013,
	title = {Earthworms, litter and soil carbon in a northern hardwood forest},
	volume = {114},
	copyright = {All rights reserved},
	doi = {10.1007/s10533-012-9808-y},
	abstract = {The important role of soil carbon (C) in the global C cycle has stimulated interest in better understanding the mechanisms regulating soil C storage and its stabilization. Exotic earthworm invasion of northern forest soils in North America can affect soil C pools, and we examined their effects on these mechanisms by adding 13C labeled leaf litter to adjacent northern hardwood forests with and without earthworms. Two types of labeled litter were produced, one with the 13C more concentrated in structural (S) components and the other in non-structural (NS) components, to evaluate the role of biochemical differences in soil C stabilization. Earthworm invasions have reduced soil C storage in the upper 20 cm of the soil profile by 37 \%, mostly by eliminating surface organic horizons. Despite rapid mixing of litter into mineral soil and its incorporation into aggregates, mineral soil C has not increased in the presence of earthworms. Incorporation of litter C into soil and microbial biomass was not affected by biochemical differences between S versus NS labeled litter although NS litter C was assimilated more readily into earthworm biomass and S litter C into fungal hyphae. Apparently, the net effect of earthworm mixing of litter and forest floor C into mineral soil, plus stabilization of that C in aggregates, is counterbalanced by earthworm bioturbation and possible priming effects. Our results support recent arguments that biochemical recalcitrance is not a major contributor to the stabilization of soil C. ? 2012 Springer Science+Business Media Dordrecht.},
	journal = {Biogeochemistry},
	author = {Fahey, Timothy J. and Yavitt, Joseph B. and Sherman, Ruth E. and Maerz, John C. and Groffman, Peter M. and Fisk, Melany C. and Bohlen, Patrick J.},
	year = {2013},
	keywords = {Decomposition, Fungal hyphae, Isotop, [Aggregation},
	pages = {DOI 10.1007/s10533--012--9808--y},
}

The important role of soil carbon (C) in the global C cycle has stimulated interest in better understanding the mechanisms regulating soil C storage and its stabilization. Exotic earthworm invasion of northern forest soils in North America can affect soil C pools, and we examined their effects on these mechanisms by adding 13C labeled leaf litter to adjacent northern hardwood forests with and without earthworms. Two types of labeled litter were produced, one with the 13C more concentrated in structural (S) components and the other in non-structural (NS) components, to evaluate the role of biochemical differences in soil C stabilization. Earthworm invasions have reduced soil C storage in the upper 20 cm of the soil profile by 37 %, mostly by eliminating surface organic horizons. Despite rapid mixing of litter into mineral soil and its incorporation into aggregates, mineral soil C has not increased in the presence of earthworms. Incorporation of litter C into soil and microbial biomass was not affected by biochemical differences between S versus NS labeled litter although NS litter C was assimilated more readily into earthworm biomass and S litter C into fungal hyphae. Apparently, the net effect of earthworm mixing of litter and forest floor C into mineral soil, plus stabilization of that C in aggregates, is counterbalanced by earthworm bioturbation and possible priming effects. Our results support recent arguments that biochemical recalcitrance is not a major contributor to the stabilization of soil C. ? 2012 Springer Science+Business Media Dordrecht.

@article{fahey_erratum_2013,
	title = {Erratum to: {Earthworms}, litter and soil carbon in a northern hardwood forest ({Biogeochemistry}, 10.1007/s10533-012-9808-y)},
	volume = {115},
	copyright = {All rights reserved},
	doi = {10.1007/s10533-013-9867-8},
	journal = {Biogeochemistry},
	author = {Fahey, Timothy J. and Yavitt, Joseph B. and Sherman, Ruth E. and Maerz, John C. and Groffman, Peter M. and Fisk, Melany C. and Bohlen, Patrick J.},
	year = {2013},
	pages = {431},
}

@article{milanovich_realistic_2013,
	title = {Realistic fasting does not affect stable isotope levels of a metabolically efficient salamander},
	volume = {47},
	copyright = {All rights reserved},
	doi = {10.1670/12-223},
	abstract = {Stable isotopes are commonly used to examine various aspects of animal ecology. The use of stable isotopes generally proceeds under the implicit assumption that resource use is the only factor driving variation in stable isotope levels; however, a wealth of studies demonstrate that a range of common ecological factors can affect the behavior of stable isotopes in animal tissues and potentially confound inferences. For example, studies of some invertebrates and endothermic vertebrates show that animals fasted for ecologically realistic time periods have higher nitrogen (?15N) or lower carbon (?13C). We examined whether realistic fasting would influence the stable isotope composition of one of the most metabolically efficient ectothermic vertebrates, the Eastern Red-backed Salamander, Plethodon cinereus. We fasted salamanders for 7, 14, 21, 28, or 35-day intervals and examined whether ?15N or ?13C levels of tissues changed between fasted and fed animals. We investigated whether body condition (body mass to length and C:N an index of lipid levels) declined in fasted animals and whether there was a relationship between C:N and ?15N or ?13C. Body mass to length index and C:N, ?13C, and ?15N of tail and liver tissues did not differ between fasted and fed animals between 7 and 35 days. Because of their extreme metabolic efficiency, vertebrate ectotherms such as lungless salamanders (Plethodontidae) may not show the effects of fasting on stable isotopes observed in endothermic vertebrates and some invertebrates. This difference should lead to simpler interpretation of stable isotope results from field studies of these animals. ? 2013 Society for the Study of Amphibians and Reptiles.},
	number = {4},
	journal = {Journal of Herpetology},
	author = {Milanovich, J.R. and Maerz, J.C.},
	year = {2013},
	pages = {544--548},
}

Stable isotopes are commonly used to examine various aspects of animal ecology. The use of stable isotopes generally proceeds under the implicit assumption that resource use is the only factor driving variation in stable isotope levels; however, a wealth of studies demonstrate that a range of common ecological factors can affect the behavior of stable isotopes in animal tissues and potentially confound inferences. For example, studies of some invertebrates and endothermic vertebrates show that animals fasted for ecologically realistic time periods have higher nitrogen (?15N) or lower carbon (?13C). We examined whether realistic fasting would influence the stable isotope composition of one of the most metabolically efficient ectothermic vertebrates, the Eastern Red-backed Salamander, Plethodon cinereus. We fasted salamanders for 7, 14, 21, 28, or 35-day intervals and examined whether ?15N or ?13C levels of tissues changed between fasted and fed animals. We investigated whether body condition (body mass to length and C:N an index of lipid levels) declined in fasted animals and whether there was a relationship between C:N and ?15N or ?13C. Body mass to length index and C:N, ?13C, and ?15N of tail and liver tissues did not differ between fasted and fed animals between 7 and 35 days. Because of their extreme metabolic efficiency, vertebrate ectotherms such as lungless salamanders (Plethodontidae) may not show the effects of fasting on stable isotopes observed in endothermic vertebrates and some invertebrates. This difference should lead to simpler interpretation of stable isotope results from field studies of these animals. ? 2013 Society for the Study of Amphibians and Reptiles.

@article{crawford_estimating_2013,
	title = {Estimating the consequences of multiple threats and management strategies for semi-aquatic turtles},
	volume = {51},
	copyright = {All rights reserved},
	doi = {10.1111/1365-2664.12194},
	abstract = {Summary: Roads are pervasive fixtures on most landscapes but are typically among many factors contributing to wildlife population declines. Addressing road mortality as part of larger conservation efforts is challenging because it can be difficult to measure per capita mortality from roads and other concurrent threats. We used 4 years of mark-recapture-recovery data for diamondback terrapins Malaclemys terrapin on a causeway in Georgia, USA, to directly estimate threats of adult road mortality and nest predation, contrast the consequences to population growth using stage-based matrix models and make management recommendations to stabilize the population. Mean estimated annual adult road mortality was 11?1\% (range = 4?4-16?4\%). Estimated annual nest predation was 61?9\%. We estimated that the population was declining (? {\textless} 0?98) in all scenarios where both threats were included. Variation in adult survival was the most influential (highest elasticity) contributor to population growth relative to other demographic rates; however, ? would remain below 1 with any nest predation rate exceeding our estimate even if actions to mitigate road mortality were 100\% effective. Synthesis and applications. Our study provides some of the first direct estimates of vehicle mortality rates and shows that mortality can remain sufficiently high among years to cause population declines. We also demonstrate that management actions focused on singular threats are inadequate for recovering populations. We conclude that integrated road and predator management is necessary to conserve turtle populations, and we suggest alternative strategies to compensate for some vehicle mortality and nest depredation. Our study provides some of the first direct estimates of vehicle mortality rates and shows that mortality can remain sufficiently high among years to cause population declines. We also demonstrate that management actions focused on singular threats are inadequate for recovering populations. We conclude that integrated road and predator management is necessary to conserve turtle populations, and we suggest alternative strategies to compensate for some vehicle mortality and nest depredation. ? 2013 British Ecological Society.},
	number = {2},
	journal = {Journal of Applied Ecology},
	author = {Crawford, B.A. and Maerz, J.C. and Nibbelink, N.P. and Buhlmann, K.A. and Norton, T.M.},
	year = {2013},
	keywords = {Malaclemys terrapin, Matrix, [Diamondback terrapin},
}

Summary: Roads are pervasive fixtures on most landscapes but are typically among many factors contributing to wildlife population declines. Addressing road mortality as part of larger conservation efforts is challenging because it can be difficult to measure per capita mortality from roads and other concurrent threats. We used 4 years of mark-recapture-recovery data for diamondback terrapins Malaclemys terrapin on a causeway in Georgia, USA, to directly estimate threats of adult road mortality and nest predation, contrast the consequences to population growth using stage-based matrix models and make management recommendations to stabilize the population. Mean estimated annual adult road mortality was 11?1% (range = 4?4-16?4%). Estimated annual nest predation was 61?9%. We estimated that the population was declining (? \textless 0?98) in all scenarios where both threats were included. Variation in adult survival was the most influential (highest elasticity) contributor to population growth relative to other demographic rates; however, ? would remain below 1 with any nest predation rate exceeding our estimate even if actions to mitigate road mortality were 100% effective. Synthesis and applications. Our study provides some of the first direct estimates of vehicle mortality rates and shows that mortality can remain sufficiently high among years to cause population declines. We also demonstrate that management actions focused on singular threats are inadequate for recovering populations. We conclude that integrated road and predator management is necessary to conserve turtle populations, and we suggest alternative strategies to compensate for some vehicle mortality and nest depredation. Our study provides some of the first direct estimates of vehicle mortality rates and shows that mortality can remain sufficiently high among years to cause population declines. We also demonstrate that management actions focused on singular threats are inadequate for recovering populations. We conclude that integrated road and predator management is necessary to conserve turtle populations, and we suggest alternative strategies to compensate for some vehicle mortality and nest depredation. ? 2013 British Ecological Society.

@article{bradford_root_2012,
	title = {Root carbon flow from an invasive plant to belowground foodwebs},
	volume = {359},
	copyright = {All rights reserved},
	doi = {10.1007/s11104-012-1210-y},
	abstract = {Aims: Soil foodwebs are based on plant production. This production enters belowground foodwebs via numerous pathways, with root pathways likely dominating supply. Indeed, root exudation may fuel 30-50 \% of belowground activity with photosynthate fixed only hours earlier. Yet we have limited knowledge of root fluxes of recent-photosynthate from invasive plants to belowground foodwebs. Methods: Using stable isotopes, we quantify the proportion of recent-photosynthate transferred belowground from the invasive grass Microstegium vimineum A. Camus, a widespread invader of forest understory. Given its minimal root biomass ({\textasciitilde}8 \% of individual mass), we expected exudation to contribute little to belowground foodwebs. Results: Within 2 days of 13C-labeling, we recover {\textasciitilde}15 \% of photosynthate carbon in microbial biomass. Recovery in root and dissolved organic carbon pools is consistently low ({\textless}2 \%), suggesting these pools operate as 'pipelines' for carbon transport to soil microbes. The recovery of the label in wolf spiders - forest floor predators that feed on soil animals - highlights that root inputs of recent photosynthate can propagate rapidly through belowground foodwebs. Conclusions: Our results suggest that root carbon-exudation, an unexplored process of invasive grass inputs to forest foodwebs, may be an important pathway through which invasive species affect the structure and function of recipient ecosystems. ? 2012 Springer Science+Business Media B.V.},
	number = {1-2},
	journal = {Plant and Soil},
	author = {Bradford, M.A. and Strickland, M.S. and DeVore, J.L. and Maerz, J.C.},
	year = {2012},
	keywords = {Exotic species, Microstegium vi, [Detrital foodweb},
	pages = {233--244},
}

Aims: Soil foodwebs are based on plant production. This production enters belowground foodwebs via numerous pathways, with root pathways likely dominating supply. Indeed, root exudation may fuel 30-50 % of belowground activity with photosynthate fixed only hours earlier. Yet we have limited knowledge of root fluxes of recent-photosynthate from invasive plants to belowground foodwebs. Methods: Using stable isotopes, we quantify the proportion of recent-photosynthate transferred belowground from the invasive grass Microstegium vimineum A. Camus, a widespread invader of forest understory. Given its minimal root biomass (~8 % of individual mass), we expected exudation to contribute little to belowground foodwebs. Results: Within 2 days of 13C-labeling, we recover ~15 % of photosynthate carbon in microbial biomass. Recovery in root and dissolved organic carbon pools is consistently low (\textless2 %), suggesting these pools operate as 'pipelines' for carbon transport to soil microbes. The recovery of the label in wolf spiders - forest floor predators that feed on soil animals - highlights that root inputs of recent photosynthate can propagate rapidly through belowground foodwebs. Conclusions: Our results suggest that root carbon-exudation, an unexplored process of invasive grass inputs to forest foodwebs, may be an important pathway through which invasive species affect the structure and function of recipient ecosystems. ? 2012 Springer Science+Business Media B.V.

@article{cohen_traits_2012,
	title = {Traits, not origin, explain impacts of plants on larval amphibians},
	volume = {22},
	copyright = {All rights reserved},
	doi = {10.1890/11-0078.1},
	abstract = {Managing habitats for the benefit of native fauna is a priority for many government and private agencies. Often, these agencies view nonnative plants as a threat to wildlife habitat, and they seek to control or eradicate nonnative plant populations. However, little is known about how nonnative plant invasions impact native fauna, and it is unclear whether managing these plants actually improves habitat quality for resident animals. Here, we compared the impacts of native and nonnative wetland plants on three species of native larval amphibians; we also examined whether plant traits explain the observed impacts. Specifically, we measured plant litter quality (carbon: nitrogen: phosphorus ratios, and percentages of lignin and soluble phenolics) and biomass, along with a suite of environmental conditions known to affect larval amphibians (hydroperiod, temperature, dissolved oxygen, and pH). Hydroperiod and plant traits, notably soluble phenolics, litter C:N ratio, and litter N:P ratio, impacted the likelihood that animals metamorphosed, the number of animals that metamorphosed, and the length of larval period. As hydroperiod decreased, the likelihood that amphibians achieved metamorphosis and the percentage of tadpoles that successfully metamorphosed also decreased. Increases in soluble phenolics, litter N:P ratio, and litter C:N ratio decreased the likelihood that tadpoles achieved metamorphosis, decreased the percentage of tadpoles metamorphosing, decreased metamorph production (total metamorph biomass), and increased the length of larval period. Interestingly, we found no difference in metamorphosis rates and length of larval period between habitats dominated by native and nonnative plants. Our findings have important implications for habitat management. We suggest that to improve habitats for native fauna, managers should focus on assembling a plant community with desirable traits rather than focusing only on plant origin. ? 2012 by the Ecological Society of America.},
	number = {1},
	journal = {Ecological Applications},
	author = {Cohen, J.S. and Maerz, J.C. and Blossey, B.},
	year = {2012},
	keywords = {Benthic environment, Central, [Anaxyrus americanus},
	pages = {218--228},
}

Managing habitats for the benefit of native fauna is a priority for many government and private agencies. Often, these agencies view nonnative plants as a threat to wildlife habitat, and they seek to control or eradicate nonnative plant populations. However, little is known about how nonnative plant invasions impact native fauna, and it is unclear whether managing these plants actually improves habitat quality for resident animals. Here, we compared the impacts of native and nonnative wetland plants on three species of native larval amphibians; we also examined whether plant traits explain the observed impacts. Specifically, we measured plant litter quality (carbon: nitrogen: phosphorus ratios, and percentages of lignin and soluble phenolics) and biomass, along with a suite of environmental conditions known to affect larval amphibians (hydroperiod, temperature, dissolved oxygen, and pH). Hydroperiod and plant traits, notably soluble phenolics, litter C:N ratio, and litter N:P ratio, impacted the likelihood that animals metamorphosed, the number of animals that metamorphosed, and the length of larval period. As hydroperiod decreased, the likelihood that amphibians achieved metamorphosis and the percentage of tadpoles that successfully metamorphosed also decreased. Increases in soluble phenolics, litter N:P ratio, and litter C:N ratio decreased the likelihood that tadpoles achieved metamorphosis, decreased the percentage of tadpoles metamorphosing, decreased metamorph production (total metamorph biomass), and increased the length of larval period. Interestingly, we found no difference in metamorphosis rates and length of larval period between habitats dominated by native and nonnative plants. Our findings have important implications for habitat management. We suggest that to improve habitats for native fauna, managers should focus on assembling a plant community with desirable traits rather than focusing only on plant origin. ? 2012 by the Ecological Society of America.

@article{milanovich_assessing_2012,
	title = {Assessing the use of non-lethal tail clips for measuring stable isotopes of plethodontid salamanders},
	volume = {7},
	copyright = {All rights reserved},
	abstract = {Stable isotopes are increasingly used in ecology to study the diets, trophic position, and migratory patterns of wildlife including herpetofauna. When using stable isotopes, it is important to consider which tissues can or should be sampled, and how selecting tissues may affect the inferences drawn from stable isotope data. Amphibians offer fewer tissues than other larger organisms that can be harvested in sufficient quantity without killing the animal; however, many salamanders have tails that readily autotomize and regenerate. We used three species of plethodontid salamander (Plethodon cinereus, P. metcalfi, and Desmognathus quadramaculatus) to determine whether distal tail tissue had carbon and nitrogen stable isotope values comparable to commonly used tissues (liver and whole carcass [minus the liver and gonads]) that must be collected lethally. We found that variation in carbon values (?13C) within and among tissues was negatively correlated with C:N (an indication of high lipid content). Nitrogen (?15N) and Carbon (?13C) values (once adjusted for C:N) of tail tissue were positively correlated with values for carcass tissue, and tail ?15N values were positively correlated and biased with ?15N values for liver tissue. Adjusted ?13C values for tail tissue were unbiased and had weaker positive correlations with ?13C values for liver tissue compared to whole carcass. The weak correlation between adjusted ?13C values of tail and liver tissues may reflect differences in turnover rates between the two tissues. Our data show that, with calibration, non-lethal collection of tail clips is a suitable substitute to lethal tissue collection for measuring ?13C and ?15N of plethodontid salamanders.},
	number = {1},
	journal = {Herpetological Conservation and Biology},
	author = {Milanovich, J.R. and Maerz, J.C.},
	year = {2012},
	keywords = {Diet, Nitrogen, Plethodontidae, Salamande, [Carbon},
	pages = {67--74},
}

Stable isotopes are increasingly used in ecology to study the diets, trophic position, and migratory patterns of wildlife including herpetofauna. When using stable isotopes, it is important to consider which tissues can or should be sampled, and how selecting tissues may affect the inferences drawn from stable isotope data. Amphibians offer fewer tissues than other larger organisms that can be harvested in sufficient quantity without killing the animal; however, many salamanders have tails that readily autotomize and regenerate. We used three species of plethodontid salamander (Plethodon cinereus, P. metcalfi, and Desmognathus quadramaculatus) to determine whether distal tail tissue had carbon and nitrogen stable isotope values comparable to commonly used tissues (liver and whole carcass [minus the liver and gonads]) that must be collected lethally. We found that variation in carbon values (?13C) within and among tissues was negatively correlated with C:N (an indication of high lipid content). Nitrogen (?15N) and Carbon (?13C) values (once adjusted for C:N) of tail tissue were positively correlated with values for carcass tissue, and tail ?15N values were positively correlated and biased with ?15N values for liver tissue. Adjusted ?13C values for tail tissue were unbiased and had weaker positive correlations with ?13C values for liver tissue compared to whole carcass. The weak correlation between adjusted ?13C values of tail and liver tissues may reflect differences in turnover rates between the two tissues. Our data show that, with calibration, non-lethal collection of tail clips is a suitable substitute to lethal tissue collection for measuring ?13C and ?15N of plethodontid salamanders.

@incollection{webster_water_2012,
	title = {Water {Quality} and {Exurbanization} in {Southern} {Appalachian} {Streams}},
	copyright = {All rights reserved},
	isbn = {978-0-470-68208-1},
	abstract = {Many rural areas of the United States are undergoing increasing development pressure from surrounding metropolitan areas, a phenomenon described as 'exurbanization'. This study examines how stream chemistry in a traditionally rural area of the southern Appalachian Mountains is being influenced by changes in both land cover and land use. Results illustrate the importance of distinguishing between these two measures. Nitrate and specific conductance were well related to catchment-scale land cover. Variables associated with particle transport, such as turbidity, were not well predicted by either catchment land cover or land use, but relationships with land use were somewhat clearer because development and agricultural land-use occur primarily in the valleys where land disturbance can more directly affect sediment inputs to streams. However, recent residential development is now occurring largely on mountainsides rather than in valleys. This mountainside development is associated with higher stream nitrate concentrations and degraded water quality to downstream communities. The paradox of exurbanization is that by moving from the city to enjoy forested and rural landscapes, people threaten the quality of life in their new communities and also in their old ones downstream. ? 2012 John Wiley \& Sons, Ltd.},
	booktitle = {Catchment {Conservation}, {Ecosystem} {Integrity} and {Threats} to {River} {Systems}},
	author = {Webster, J.R. and Benfield, E.F. and Cecala, K.K. and Chamblee, J.F. and Dehring, C.A. and Gragson, T. and Cymerman, J.H. and Jackson, C.R. and Knoepp, J.D. and Leigh, D.S. and Maerz, J.C. and Pringle, C. and Valett, H.M.},
	year = {2012},
	doi = {10.1002/9781119961819.ch8},
	note = {Publication Title: River Conservation and Management},
	keywords = {Coweeta Research Laboratory, [Catchment land-use},
	pages = {91--106},
}

Many rural areas of the United States are undergoing increasing development pressure from surrounding metropolitan areas, a phenomenon described as 'exurbanization'. This study examines how stream chemistry in a traditionally rural area of the southern Appalachian Mountains is being influenced by changes in both land cover and land use. Results illustrate the importance of distinguishing between these two measures. Nitrate and specific conductance were well related to catchment-scale land cover. Variables associated with particle transport, such as turbidity, were not well predicted by either catchment land cover or land use, but relationships with land use were somewhat clearer because development and agricultural land-use occur primarily in the valleys where land disturbance can more directly affect sediment inputs to streams. However, recent residential development is now occurring largely on mountainsides rather than in valleys. This mountainside development is associated with higher stream nitrate concentrations and degraded water quality to downstream communities. The paradox of exurbanization is that by moving from the city to enjoy forested and rural landscapes, people threaten the quality of life in their new communities and also in their old ones downstream. ? 2012 John Wiley & Sons, Ltd.

@article{burke_invasion_2011,
	title = {Invasion by exotic earthworms alters biodiversity and communities of litter- and soil-dwelling oribatid mites},
	volume = {3},
	copyright = {All rights reserved},
	doi = {10.3390/d3010155},
	abstract = {Exotic earthworms are drivers of biotic communities in invaded North American forest stands. Here we used ecologically important oribatid mite (Arachnida: Acari) communities, as model organisms to study the responses of litter- and soil-dwelling microarthropod communities to exotic earthworm invasion in a northern temperate forest. Litter- and soil-dwelling mites were sampled in 2008-2009 from forest areas: (1) with no earthworms; (2) those with epigeic and endogeic species, including Lumbricus rubellus Hoffmeister; and (3) those with epigeic, endogeic, and anecic earthworms including L. terrestris L. Species richness and diversity of litter- and soil-dwelling (0-2 cm soil depth) oribatid mites was 1-2 times higher in sites without earthworms than in sites with worms. Similarly, litter-dwelling oribatid mites were between 72 and 1,210 times more abundant in earthworm-free sites than in sites with worms. Among earthworm invaded sites, abundance of litter-dwelling oribatid mites in sites without the anecic L. terrestris was twice as high in May and 28 times higher in October, compared to sites with L. terrestris. Species richness, diversity, and abundance of oribatid mites were greater in litter-layers than in the soil-layers that showed a varied response to earthworm invasion. Species compositions of both litter- and soil-dwelling oribatid mite communities of forests with no earthworms were markedly different from those with earthworms. We conclude that exotic earthworm invasions are associated with significant declines of speciesdiversity, numbers, and compositional shifts in litter- and soil-inhabiting communities. These faunal shifts may contribute to earthworm effects on soil processes and food web dynamics in historically earthworm-free, northern temperate forests. ? 2011 by the authors.},
	number = {1},
	journal = {Diversity},
	author = {Burke, J.L. and Maerz, J.C. and Milanovich, J.R. and Fisk, M.C. and Gandhi, K.J.K.},
	year = {2011},
	keywords = {Biodiversity, Earthworms, Exotic speci, [Acer spp.},
	pages = {155--175},
}

Exotic earthworms are drivers of biotic communities in invaded North American forest stands. Here we used ecologically important oribatid mite (Arachnida: Acari) communities, as model organisms to study the responses of litter- and soil-dwelling microarthropod communities to exotic earthworm invasion in a northern temperate forest. Litter- and soil-dwelling mites were sampled in 2008-2009 from forest areas: (1) with no earthworms; (2) those with epigeic and endogeic species, including Lumbricus rubellus Hoffmeister; and (3) those with epigeic, endogeic, and anecic earthworms including L. terrestris L. Species richness and diversity of litter- and soil-dwelling (0-2 cm soil depth) oribatid mites was 1-2 times higher in sites without earthworms than in sites with worms. Similarly, litter-dwelling oribatid mites were between 72 and 1,210 times more abundant in earthworm-free sites than in sites with worms. Among earthworm invaded sites, abundance of litter-dwelling oribatid mites in sites without the anecic L. terrestris was twice as high in May and 28 times higher in October, compared to sites with L. terrestris. Species richness, diversity, and abundance of oribatid mites were greater in litter-layers than in the soil-layers that showed a varied response to earthworm invasion. Species compositions of both litter- and soil-dwelling oribatid mite communities of forests with no earthworms were markedly different from those with earthworms. We conclude that exotic earthworm invasions are associated with significant declines of speciesdiversity, numbers, and compositional shifts in litter- and soil-inhabiting communities. These faunal shifts may contribute to earthworm effects on soil processes and food web dynamics in historically earthworm-free, northern temperate forests. ? 2011 by the authors.

@article{byers_using_2011,
	title = {Using parasitic trematode larvae to quantify an elusive vertebrate host},
	volume = {25},
	copyright = {All rights reserved},
	issn = {1523-1739 (Electronic) 0888-8892 (Linking)},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/21029163},
	doi = {10.1111/j.1523-1739.2010.01583.x},
	abstract = {Digenean trematode parasites require multiple host species to complete their life cycles, and their abundance can often be strongly correlated with the abundance of their host species. Species richness and abundance of parasites in easily sampled host species may yield an accurate estimate of the species richness and abundance of other hosts in a parasite's life cycle that are difficult to survey directly. Accordingly, we investigated whether prevalence and mean abundance of trematodes could be used to estimate the abundance of one of their host species, diamondback terrapins (Malaclemys terrapin), which are difficult to sample and are designated as near threatened (by the International Union for Conservation of Nature [IUCN Red List]) along some U.S. coasts. As an adult the trematode Pleurogonius malaclemys is specific to terrapins. Its larval stages live first inside mud snails (Ilyanassa obsoleta) and are subsequently shed into the environment where they form external metacercarial cysts on hard surfaces such as snail opercula. The life cycle of P. malaclemys is completed when terrapins ingest these cysts. At 12 sites along the coast of Georgia (U.S.A.), we determined the prevalence of internal P. malaclemys larvae in mud snails (proportion of infected snails in a population) and the prevalence and mean abundance of external trematode cysts. We examined whether these data were correlated with terrapin abundance, which we estimated with mark-recapture methods. The abundance of external cysts and salinity explained {\textgreater}/=59\% of the variability in terrapin abundance. We suggest that dependent linkages between the life stages of multihost parasites make them reliable predictors of host species' abundance, including hosts with abundances that are challenging to quantify directly.},
	number = {1},
	journal = {Conservation Biology},
	author = {Byers, J E and Altman, I and Grosse, A M and Huspeni, T C and Maerz, J C},
	year = {2011},
	keywords = {*Endangered Species, Animals, Georgia, Host-Parasite Interactions, Larva/physiology, Life Cycle Stages, Population Density, Population Dynamics, Snails/parasitology, Trematoda/*physiology, Turtles/*parasitology},
	pages = {85--93},
}

Digenean trematode parasites require multiple host species to complete their life cycles, and their abundance can often be strongly correlated with the abundance of their host species. Species richness and abundance of parasites in easily sampled host species may yield an accurate estimate of the species richness and abundance of other hosts in a parasite's life cycle that are difficult to survey directly. Accordingly, we investigated whether prevalence and mean abundance of trematodes could be used to estimate the abundance of one of their host species, diamondback terrapins (Malaclemys terrapin), which are difficult to sample and are designated as near threatened (by the International Union for Conservation of Nature [IUCN Red List]) along some U.S. coasts. As an adult the trematode Pleurogonius malaclemys is specific to terrapins. Its larval stages live first inside mud snails (Ilyanassa obsoleta) and are subsequently shed into the environment where they form external metacercarial cysts on hard surfaces such as snail opercula. The life cycle of P. malaclemys is completed when terrapins ingest these cysts. At 12 sites along the coast of Georgia (U.S.A.), we determined the prevalence of internal P. malaclemys larvae in mud snails (proportion of infected snails in a population) and the prevalence and mean abundance of external trematode cysts. We examined whether these data were correlated with terrapin abundance, which we estimated with mark-recapture methods. The abundance of external cysts and salinity explained \textgreater/=59% of the variability in terrapin abundance. We suggest that dependent linkages between the life stages of multihost parasites make them reliable predictors of host species' abundance, including hosts with abundances that are challenging to quantify directly.

@article{davis_assessing_2011,
	title = {Assessing stress levels of captive-reared amphibians with hematological data: {Implications} for conservation initiatives},
	volume = {45},
	copyright = {All rights reserved},
	doi = {10.1670/10-180.1},
	abstract = {Larval amphibians are increasingly being reared for conservation initiatives to bolster declining populations. Few researchers, however, have asked whether reared individuals are functionally equivalent to their wild counterparts. Compared with those in the wild, amphibians reared in captivity may develop in relatively stress-free environments, because they are usually fed ad libitum, raised in the absence of predators and pathogens and in controlled environments. Thus, with few challenges throughout development, would their resting stress levels or reactions to acute stressors be normal? We addressed this question by rearing Litobates sphenocephalus and Ambystoma opacum from eggs and 10-day-old larvae through to late larval stages in artificial pond environments and by determining their ratios of neutrophils (N) to lymphocytes (L) (two leukocytes that covary with stress hormones) before and after a standardized stressor. We obtained similar samples from wild-caught larvae of equivalent developmental stages and from the same source pond. Baseline and stress-induced N?L ratios of reared L. sphenocephalus were statistically similar to those of wild individuals. In contrast, baseline N?L ratios of reared A. opacum were slightly higher than those of wild individuals. In general, the magnitude of the leukocyte response to stress for both species (a 3-fold increase in N?L over baseline), was similar to that of wild individuals, suggesting that captive-reared amphibians are capable of mounting a normal physiological stress response. Although this last point provides support for the use of captive-rearing for conservation and research purposes, the unusually high baseline N?L ratios of reared salamanders will require additional research to determine the functional meaning. ? 2011 Society for the Study of Amphibians and Reptiles.},
	number = {1},
	journal = {Journal of Herpetology},
	author = {Davis, A.K. and Maerz, J.C.},
	year = {2011},
	pages = {40--44},
}

Larval amphibians are increasingly being reared for conservation initiatives to bolster declining populations. Few researchers, however, have asked whether reared individuals are functionally equivalent to their wild counterparts. Compared with those in the wild, amphibians reared in captivity may develop in relatively stress-free environments, because they are usually fed ad libitum, raised in the absence of predators and pathogens and in controlled environments. Thus, with few challenges throughout development, would their resting stress levels or reactions to acute stressors be normal? We addressed this question by rearing Litobates sphenocephalus and Ambystoma opacum from eggs and 10-day-old larvae through to late larval stages in artificial pond environments and by determining their ratios of neutrophils (N) to lymphocytes (L) (two leukocytes that covary with stress hormones) before and after a standardized stressor. We obtained similar samples from wild-caught larvae of equivalent developmental stages and from the same source pond. Baseline and stress-induced N?L ratios of reared L. sphenocephalus were statistically similar to those of wild individuals. In contrast, baseline N?L ratios of reared A. opacum were slightly higher than those of wild individuals. In general, the magnitude of the leukocyte response to stress for both species (a 3-fold increase in N?L over baseline), was similar to that of wild individuals, suggesting that captive-reared amphibians are capable of mounting a normal physiological stress response. Although this last point provides support for the use of captive-rearing for conservation and research purposes, the unusually high baseline N?L ratios of reared salamanders will require additional research to determine the functional meaning. ? 2011 Society for the Study of Amphibians and Reptiles.

@article{davis_effect_2011,
	title = {Effect of {Trapping} {Method} on {Leukocyte} {Profiles} of {Black}-{Chested} {Spiny}-{Tailed} {Iguanas} ({Ctenosaura} melanosterna): {Implications} for {Zoologists} in the {Field}},
	volume = {2011},
	copyright = {All rights reserved},
	issn = {2090-522X 2090-5238},
	doi = {10.5402/2011/384825},
	abstract = {When wild animals are captured for zoological research, researchers must choose a method of capture, and often this can be some form of passive, baited cage trap, or a direct capture with nets or nooses. If information on basal levels of circulating leukocytes is a goal, these two methods may provide different information, since recent evidence indicates that animals that enter cage traps experience stress, and, elevated stress hormones are known to alter leukocyte numbers in circulation by lowering lymphocyte and raising heterophil numbers. We tested this idea using a study of Black-chested Spiny-tailed iguanas (Ctenosaura melanosterna), which were captured using cage traps (n = 23) and noose (n = 27). Based on cell counts made from blood smears, iguanas caught with cage traps had significantly greater relative and absolute numbers of heterophils and higher heterophil-lymphocyte (H-L) ratios than those captured by noose. Cage-trapped animals also had a nonsignificant reduction in lymphocyte numbers. Similar trends were observed in animals captured with both methods. These patterns are consistent with the effects of stress hormones on white blood cell distributions and indicate that caution must be taken in interpreting leukocyte data from studies of wild animals captured with cage traps.},
	journal = {ISRN Zoology},
	author = {Davis, Andrew K and Ruyle, Leslie E and Maerz, John C},
	year = {2011},
	pages = {Article ID 384825},
}

When wild animals are captured for zoological research, researchers must choose a method of capture, and often this can be some form of passive, baited cage trap, or a direct capture with nets or nooses. If information on basal levels of circulating leukocytes is a goal, these two methods may provide different information, since recent evidence indicates that animals that enter cage traps experience stress, and, elevated stress hormones are known to alter leukocyte numbers in circulation by lowering lymphocyte and raising heterophil numbers. We tested this idea using a study of Black-chested Spiny-tailed iguanas (Ctenosaura melanosterna), which were captured using cage traps (n = 23) and noose (n = 27). Based on cell counts made from blood smears, iguanas caught with cage traps had significantly greater relative and absolute numbers of heterophils and higher heterophil-lymphocyte (H-L) ratios than those captured by noose. Cage-trapped animals also had a nonsignificant reduction in lymphocyte numbers. Similar trends were observed in animals captured with both methods. These patterns are consistent with the effects of stress hormones on white blood cell distributions and indicate that caution must be taken in interpreting leukocyte data from studies of wild animals captured with cage traps.

@article{fahey_transport_2011,
	title = {Transport of carbon and nitrogen between litter and soil organic matter in a northern hardwood forest},
	volume = {14},
	copyright = {All rights reserved},
	issn = {1432-9840},
	url = {http://dx.doi.org/10.1007/s10021-011-9414-1},
	doi = {10.1007/s10021-011-9414-1},
	abstract = {We used sugar maple litter double-labeled with 13C and 15N to quantify fluxes of carbon (C) and nitrogen (N) between litter and soil in a northern hardwood forest and the retention of litter C and N in soil. Two cohorts of litter were compared, one in which the label was preferentially incorporated into non-structural tissue and the other structural tissue. Loss of 13C from this litter generally followed dry mass and total C loss whereas loss of 15N (20–30\% in 1 year) was accompanied by large increases of total N content of this decaying litter (26–32\%). Enrichment of 13C and 15N was detected in soil down to 10–15 cm depth. After 6 months of decay (November–May) 36–43\% of the 13C released from the litter was recovered in the soil, with no differences between the structural and non-structural labeled litter. By October the percentage recovery of litter 13C in soil was much lower (16\%). The C released from litter and remaining in soil organic matter (SOM) after 1 year represented over 30 g C m−2 y−1 of SOM accumulation. Recovery of litter 15N in soil was much higher than for C (over 90\%) and in May 15N was mostly in organic horizons whereas by October it was mostly in 0–10 cm mineral soil. A small proportion of this N was recovered as inorganic N (2–6\%). Recovery of 15N in microbial biomass was higher in May (13–15\%) than in October (about 5\%). The C:N ratio of the SOM and microbial biomass derived from the labeled litter was much higher for the structural than the non-structural litter and for the forest floor than mineral SOM, illustrating the interactive role of substrates and microbial activity in regulating the C:N stoichiometry of forest SOM formation. These results for a forest ecosystem long exposed to chronically high atmospheric N deposition (ca. 10 kg N ha−1 y−1) suggest possible mechanisms of N retention in soil: increased organic N leaching from fresh litter and reduced fungal transport of N from soil to decaying litter may promote N stabilization in mineral SOM even at a relatively low C:N ratio.},
	journal = {Ecosystems},
	author = {Fahey, Timothy J. and Yavitt, Joseph B. and Sherman, Ruth E. and Groffman, Peter M. and Fisk, Melany C. and Maerz, John C.},
	year = {2011},
	note = {Publisher: Springer New York},
	keywords = {Biomedical and Life Sciences},
	pages = {326--340},
}

We used sugar maple litter double-labeled with 13C and 15N to quantify fluxes of carbon (C) and nitrogen (N) between litter and soil in a northern hardwood forest and the retention of litter C and N in soil. Two cohorts of litter were compared, one in which the label was preferentially incorporated into non-structural tissue and the other structural tissue. Loss of 13C from this litter generally followed dry mass and total C loss whereas loss of 15N (20–30% in 1 year) was accompanied by large increases of total N content of this decaying litter (26–32%). Enrichment of 13C and 15N was detected in soil down to 10–15 cm depth. After 6 months of decay (November–May) 36–43% of the 13C released from the litter was recovered in the soil, with no differences between the structural and non-structural labeled litter. By October the percentage recovery of litter 13C in soil was much lower (16%). The C released from litter and remaining in soil organic matter (SOM) after 1 year represented over 30 g C m−2 y−1 of SOM accumulation. Recovery of litter 15N in soil was much higher than for C (over 90%) and in May 15N was mostly in organic horizons whereas by October it was mostly in 0–10 cm mineral soil. A small proportion of this N was recovered as inorganic N (2–6%). Recovery of 15N in microbial biomass was higher in May (13–15%) than in October (about 5%). The C:N ratio of the SOM and microbial biomass derived from the labeled litter was much higher for the structural than the non-structural litter and for the forest floor than mineral SOM, illustrating the interactive role of substrates and microbial activity in regulating the C:N stoichiometry of forest SOM formation. These results for a forest ecosystem long exposed to chronically high atmospheric N deposition (ca. 10 kg N ha−1 y−1) suggest possible mechanisms of N retention in soil: increased organic N leaching from fresh litter and reduced fungal transport of N from soil to decaying litter may promote N stabilization in mineral SOM even at a relatively low C:N ratio.

@article{grosse_effects_2011,
	title = {Effects of roads and crabbing pressures on diamondback terrapin populations in {Coastal} {Georgia}},
	volume = {75},
	copyright = {All rights reserved},
	doi = {10.1002/jwmg.104},
	abstract = {Human activities, including the harvesting of natural resources and land development, place substantial pressure on wildlife. The diamondback terrapin (Malaclemys terrapin) is a small, estuarine species of emydid turtle in decline and at risk due to a suite of human activities. Vehicle-induced mortality from increasing coastal traffic and bycatch mortality in crab pots have been recognized as 2 of the primary conservation concerns for terrapins. We used mark-recapture estimates of terrapin density and sex ratio from repeated seining samples of 29 randomly stratified selected tidal creeks to evaluate the current relationships between road and crabbing pressures and the abundance, sex ratio, and size distribution of terrapin populations along the Georgia coast. We obtained 2005 captures of 1,547 individual terrapins among 29 tidal creeks sampled. Population density estimates ranged from 0 to 1,040 terrapins/km among tidal creeks with a median density of 65 terrapins/km. Among all sites, terrapin density declined with increasing crabbing activity within the creek, but was not related to proximity to roads. Sex ratios did not vary significantly with crabbing activity or proximity to roads; however, we found a significantly larger proportion of smaller-sized terrapins in creeks with no crabbing activity. Although roads may have significant localized effects on terrapin populations, we found no measurable association between proximity to roads and current variation in terrapin density along the Georgia coast. However, we did find that terrapin density and the proportion of smaller sized individuals within the population were negatively associated with crabbing activities. Bycatch from commercial and recreational activities threaten many species. We add to a growing body of research showing crabbing activities are affecting diamondback terrapin populations across much of the species' range. States committed to the conservation of terrapins and coastal species should focus on reducing bycatch risk; for example by regulating soak times and locations, requiring the use of bycatch reduction devices, and removing abandoned or lost crab pots from coastal habitats. ? 2011 The Wildlife Society.},
	number = {4},
	journal = {Journal of Wildlife Management},
	author = {Grosse, A.M. and Maerz, J.C. and Hepinstall-Cymerman, J. and Dorcas, M.E.},
	year = {2011},
	keywords = {Diamondback terrapin, Malaclemys terra, [Crab trap},
	pages = {762--770},
}

Human activities, including the harvesting of natural resources and land development, place substantial pressure on wildlife. The diamondback terrapin (Malaclemys terrapin) is a small, estuarine species of emydid turtle in decline and at risk due to a suite of human activities. Vehicle-induced mortality from increasing coastal traffic and bycatch mortality in crab pots have been recognized as 2 of the primary conservation concerns for terrapins. We used mark-recapture estimates of terrapin density and sex ratio from repeated seining samples of 29 randomly stratified selected tidal creeks to evaluate the current relationships between road and crabbing pressures and the abundance, sex ratio, and size distribution of terrapin populations along the Georgia coast. We obtained 2005 captures of 1,547 individual terrapins among 29 tidal creeks sampled. Population density estimates ranged from 0 to 1,040 terrapins/km among tidal creeks with a median density of 65 terrapins/km. Among all sites, terrapin density declined with increasing crabbing activity within the creek, but was not related to proximity to roads. Sex ratios did not vary significantly with crabbing activity or proximity to roads; however, we found a significantly larger proportion of smaller-sized terrapins in creeks with no crabbing activity. Although roads may have significant localized effects on terrapin populations, we found no measurable association between proximity to roads and current variation in terrapin density along the Georgia coast. However, we did find that terrapin density and the proportion of smaller sized individuals within the population were negatively associated with crabbing activities. Bycatch from commercial and recreational activities threaten many species. We add to a growing body of research showing crabbing activities are affecting diamondback terrapin populations across much of the species' range. States committed to the conservation of terrapins and coastal species should focus on reducing bycatch risk; for example by regulating soak times and locations, requiring the use of bycatch reduction devices, and removing abandoned or lost crab pots from coastal habitats. ? 2011 The Wildlife Society.

@article{strickland_loss_2011,
	title = {Loss of faster-cycling soil carbon pools following grass invasion across multiple forest sites},
	volume = {43},
	copyright = {All rights reserved},
	doi = {10.1016/j.soilbio.2010.10.006},
	abstract = {It is established that invasive plant species can alter soil carbon cycling, although data are rare for late successional ecosystems. We examined effects of a grass invader (Microstegium vimineum) on soil carbon across eight sites in southeastern U.S. forests to establish which factors are related to these effects, by coupling isotopic and soil carbon fractionation approaches. Invasion was associated with declines in mass of faster-cycling, particulate organic matter (POM) carbon pools. This led to a significant decline (11\% on average) in native-derived carbon in the surface 10 cm of the soil profile. Formation of soil carbon from the invader-derived inputs partially mitigated these losses (total carbon loss 6\% on average). Our data suggest that Microstegium invasion of forest understories may accelerate carbon cycling and could result in a net loss of soil carbon from eastern U.S. forests. ? 2010 Elsevier Ltd.},
	number = {2},
	journal = {Soil Biology and Biochemistry},
	author = {Strickland, M.S. and DeVore, J.L. and Maerz, J.C. and Bradford, M.A.},
	year = {2011},
	keywords = {Carbon sequestration, Carbon sink, [Annual grass},
	pages = {452--454},
}

It is established that invasive plant species can alter soil carbon cycling, although data are rare for late successional ecosystems. We examined effects of a grass invader (Microstegium vimineum) on soil carbon across eight sites in southeastern U.S. forests to establish which factors are related to these effects, by coupling isotopic and soil carbon fractionation approaches. Invasion was associated with declines in mass of faster-cycling, particulate organic matter (POM) carbon pools. This led to a significant decline (11% on average) in native-derived carbon in the surface 10 cm of the soil profile. Formation of soil carbon from the invader-derived inputs partially mitigated these losses (total carbon loss 6% on average). Our data suggest that Microstegium invasion of forest understories may accelerate carbon cycling and could result in a net loss of soil carbon from eastern U.S. forests. ? 2010 Elsevier Ltd.

@article{sterrett_conservation_2011,
	title = {The conservation implications of riparian land use on river turtles},
	volume = {14},
	copyright = {All rights reserved},
	doi = {10.1111/j.1469-1795.2010.00394.x},
	abstract = {Agriculture is the dominant land use in the Lower Flint River Basin (LFRB) of south-western Georgia, USA, and is often a significant disturbance factor affecting streams and riparian habitats. Streams in the LFRB harbor a great diversity of freshwater turtles, which are among the many groups of aquatic fauna impacted by agricultural disturbance to riparian habitats. The objective of this study was to assess turtle diversity and abundance in both agriculturally impacted and unimpacted or restored reaches of streams in the LFRB. In 2007 and 2008, we used hoop traps and effort-managed snorkel surveys to sample turtles on 14 reaches of two streams (Ichawaynochaway and Spring Creeks). We recorded 823 captures of 674 individuals representing nine turtle species. There was a measurable association between the percentage of riparian undisturbed land cover and the number of turtles captured for the four most frequently captured species (Trachemys scripta, Graptemys barbouri, Pseudemys concinna and Sternotherus minor). We found a negative relationship between the total number of turtles captured and percentage of undisturbed land cover within a 287m buffer width due to a significant increase in the number of T. scripta in less-forested sections of the creeks; however, the number of G. barbouri captures declined with reduced undisturbed land cover. Species evenness was positively correlated with percentage of undisturbed land. These results suggest that loss of riparian forest is associated with a decline in freshwater diversity (evenness) and a decline in the abundance of the endemic, state protected G. barbouri; however, overall turtle abundance may remain stable or increase with loss of riparian forest cover due to an increase in common, cosmopolitan species. Our results suggest that maintenance or restoration of riparian forests is critical to freshwater turtle conservation. ? 2010 The Authors. Animal Conservation ? 2010 The Zoological Society of London.},
	number = {1},
	journal = {Animal Conservation},
	author = {Sterrett, S.C. and Smith, L.L. and Golladay, S.W. and Schweitzer, S.H. and Maerz, J.C.},
	year = {2011},
	keywords = {Flint river basin, Graptemys barbour, [Agriculture},
}

Agriculture is the dominant land use in the Lower Flint River Basin (LFRB) of south-western Georgia, USA, and is often a significant disturbance factor affecting streams and riparian habitats. Streams in the LFRB harbor a great diversity of freshwater turtles, which are among the many groups of aquatic fauna impacted by agricultural disturbance to riparian habitats. The objective of this study was to assess turtle diversity and abundance in both agriculturally impacted and unimpacted or restored reaches of streams in the LFRB. In 2007 and 2008, we used hoop traps and effort-managed snorkel surveys to sample turtles on 14 reaches of two streams (Ichawaynochaway and Spring Creeks). We recorded 823 captures of 674 individuals representing nine turtle species. There was a measurable association between the percentage of riparian undisturbed land cover and the number of turtles captured for the four most frequently captured species (Trachemys scripta, Graptemys barbouri, Pseudemys concinna and Sternotherus minor). We found a negative relationship between the total number of turtles captured and percentage of undisturbed land cover within a 287m buffer width due to a significant increase in the number of T. scripta in less-forested sections of the creeks; however, the number of G. barbouri captures declined with reduced undisturbed land cover. Species evenness was positively correlated with percentage of undisturbed land. These results suggest that loss of riparian forest is associated with a decline in freshwater diversity (evenness) and a decline in the abundance of the endemic, state protected G. barbouri; however, overall turtle abundance may remain stable or increase with loss of riparian forest cover due to an increase in common, cosmopolitan species. Our results suggest that maintenance or restoration of riparian forests is critical to freshwater turtle conservation. ? 2010 The Authors. Animal Conservation ? 2010 The Zoological Society of London.

@article{bradford_native_2010,
	title = {Native, insect herbivore communities derive a significant proportion of their carbon from a widespread invader of forest understories},
	volume = {12},
	copyright = {All rights reserved},
	doi = {10.1007/s10530-009-9480-x},
	abstract = {Research on natural enemies demonstrates the potential for exotic plants to be integrated into foodwebs through the activities of native herbivores. The quantitative importance of exotics as a food resource to herbivores is more difficult to ascertain. In addition, some widespread invaders appear to have minimal herbivore loads. Microstegium vimineum is one example. It is an annual, C4 grass that invades forest understories and is widespread across the eastern US. Its invasion alters the structure and composition of forests. We sampled invertebrates in a tree-canopy gap and under canopy area, and used the unique carbon isotope value of M. vimineum to estimate the quantitative importance of the invader as a food resource relative to native plants. Seven of the eight invertebrate species derived on average {\textgreater}35\% of their biomass carbon from M. vimineum, and some individuals representing both 'chewing' and 'sucking' feeding guilds derived their biomass carbon exclusively from M. vimineum. Our results show that M. vimineum can be a significant food resource for a multi-species, multi-guild, assemblage of native, invertebrate herbivores. Future work is required to assess whether M. vimineum is acquiring herbivores in other parts of its introduced range, and if so what might be the ecological consequences. ? Springer Science+Business Media B.V. 2009.},
	number = {4},
	journal = {Biological Invasions},
	author = {Bradford, M.A. and DeVore, J.L. and Maerz, J.C. and McHugh, J.V. and Smith, C.L. and Strickland, M.S.},
	year = {2010},
	keywords = {Exotic species, Grass i, [Enemy release hypothesis},
	pages = {721--724},
}

Research on natural enemies demonstrates the potential for exotic plants to be integrated into foodwebs through the activities of native herbivores. The quantitative importance of exotics as a food resource to herbivores is more difficult to ascertain. In addition, some widespread invaders appear to have minimal herbivore loads. Microstegium vimineum is one example. It is an annual, C4 grass that invades forest understories and is widespread across the eastern US. Its invasion alters the structure and composition of forests. We sampled invertebrates in a tree-canopy gap and under canopy area, and used the unique carbon isotope value of M. vimineum to estimate the quantitative importance of the invader as a food resource relative to native plants. Seven of the eight invertebrate species derived on average \textgreater35% of their biomass carbon from M. vimineum, and some individuals representing both 'chewing' and 'sucking' feeding guilds derived their biomass carbon exclusively from M. vimineum. Our results show that M. vimineum can be a significant food resource for a multi-species, multi-guild, assemblage of native, invertebrate herbivores. Future work is required to assess whether M. vimineum is acquiring herbivores in other parts of its introduced range, and if so what might be the ecological consequences. ? Springer Science+Business Media B.V. 2009.

@article{davis_effects_2010,
	title = {Effects of exogenous corticosterone on circulating leukocytes of a salamander ({Ambystoma} talpoideum) with unusually abundant eosinophils},
	volume = {2010},
	copyright = {All rights reserved},
	doi = {10.1155/2010/735937},
	abstract = {When animals become stressed, their levels of glucocorticoid hormones increase, causing white blood cells to move from tissues to circulation or vice versa. The primary alteration is an increase in the abundance of circulating neutrophils and a decrease in lymphocytes in circulation. A lesser-known effect is a decrease in the number of circulating eosinophils. Salamanders in the genus Ambystoma have unusually high numbers of circulating eosinophils, and as such, any effect of stress hormones on circulating leukocytes (especially eosinophils) of these species should be especially pronounced. We conducted an experiment to determine the effect of corticosterone administration on leukocyte counts (from blood smears) of A. talpoideum salamanders. Salamanders were captured and sampled as reference animals (n=11), given a sham injection (n=8), or injected with 0.1cc of a 100 ?g/mL corticosterone solution (n=28). After 24 hours, relative neutrophil counts were higher and relative lymphocyte counts lower, in the corticosterone group than the sham and control groups. Absolute counts showed that this effect was driven by a reduction in lymphocytes, since neutrophil counts were statistically similar across treatments. Importantly, relative and absolute numbers of eosinophils decreased in the sham and corticosterone groups, confirming the sensitivity of this cell to stress in amphibians. ? 2010 A. K. Davis and J. C. Maerz.},
	journal = {International Journal of Zoology},
	author = {Davis, A.K. and Maerz, J.C.},
	year = {2010},
	pages = {Article ID 735937},
}

When animals become stressed, their levels of glucocorticoid hormones increase, causing white blood cells to move from tissues to circulation or vice versa. The primary alteration is an increase in the abundance of circulating neutrophils and a decrease in lymphocytes in circulation. A lesser-known effect is a decrease in the number of circulating eosinophils. Salamanders in the genus Ambystoma have unusually high numbers of circulating eosinophils, and as such, any effect of stress hormones on circulating leukocytes (especially eosinophils) of these species should be especially pronounced. We conducted an experiment to determine the effect of corticosterone administration on leukocyte counts (from blood smears) of A. talpoideum salamanders. Salamanders were captured and sampled as reference animals (n=11), given a sham injection (n=8), or injected with 0.1cc of a 100 ?g/mL corticosterone solution (n=28). After 24 hours, relative neutrophil counts were higher and relative lymphocyte counts lower, in the corticosterone group than the sham and control groups. Absolute counts showed that this effect was driven by a reduction in lymphocytes, since neutrophil counts were statistically similar across treatments. Importantly, relative and absolute numbers of eosinophils decreased in the sham and corticosterone groups, confirming the sensitivity of this cell to stress in amphibians. ? 2010 A. K. Davis and J. C. Maerz.

@article{graham_overlooked_2010,
	title = {An {Overlooked} hotspot? {Rapid} biodiversity assessment reveals a region of exceptional herpetofaunal richness in the {Southeastern} {United} {States}},
	volume = {9},
	copyright = {All rights reserved},
	doi = {10.1656/058.009.0102},
	abstract = {We conducted a competitive bioblitz survey in four Georgia counties to raise awareness of a unique and species rich herpetofauna in the Pine Mountain/ Fall Line Sandhills Region of Georgia, and compared documented species of these counties to other herpetofaunas of the southeast that have known high richness and/ or were subject to thorough collection efforts. Our results demonstrate the efficacy of bioblitzes for documenting large numbers of species in a limited amount of time (62 amphibian and reptile species in only seven days, including 36 new county records and documentation of three protected species). Compared to areas of similar size, this area is among the most species-rich herpetofaunas in North America north of Mexico, with only three areas having higher documented richness. However, all areas we compared our site to have experienced much higher collection effort and contain much larger tracts of protected land. Thus, our data suggest the Pine Mountain/Fall Line Sandhills region is among the most important regions for amphibian and reptile conservation in North America.},
	number = {1},
	journal = {Southeastern Naturalist},
	author = {Graham, S.P. and Steen, D.A. and Nelson, K.T. and Durso, A.M. and Maerz, J.C.},
	year = {2010},
	pages = {19--34},
}

We conducted a competitive bioblitz survey in four Georgia counties to raise awareness of a unique and species rich herpetofauna in the Pine Mountain/ Fall Line Sandhills Region of Georgia, and compared documented species of these counties to other herpetofaunas of the southeast that have known high richness and/ or were subject to thorough collection efforts. Our results demonstrate the efficacy of bioblitzes for documenting large numbers of species in a limited amount of time (62 amphibian and reptile species in only seven days, including 36 new county records and documentation of three protected species). Compared to areas of similar size, this area is among the most species-rich herpetofaunas in North America north of Mexico, with only three areas having higher documented richness. However, all areas we compared our site to have experienced much higher collection effort and contain much larger tracts of protected land. Thus, our data suggest the Pine Mountain/Fall Line Sandhills region is among the most important regions for amphibian and reptile conservation in North America.

@article{grosse_effects_2010,
	title = {Effects of turbidity on the foraging {Success} of the {Eastern} {Painted} {Turtle}},
	volume = {2010},
	copyright = {All rights reserved},
	doi = {10.1643/CE-09-162},
	abstract = {The effect of increased turbidity levels on aquatic organisms is an increasing concern for aquatic biologists. Recent studies show reduced foraging efficiency of drift-feeding fish species, which are highly visual predators, with increasing water turbidity. Similar to fish, many aquatic turtle species are highly visual aquatic predators that may be negatively affected by increasing water turbidity. We used Eastern Painted Turtles (Chrysemys picta) to test the hypothesis that increasing water turbidity would decrease prey capture efficiency. We classically conditioned eight C. picta to search for a food item when presented with a novel stimulus, and then measured the time it took each turtle to find a prey item under a range of 26 turbidity levels (?40 nephelometric turbidity units, NTUs) presented in a random order. All turtles were successfully trained within 29 days to search for the food item when presented with the stimulus. Turbidity had no effect on the probability of successful prey capture. Turtles located the prey item in 97 of trials regardless of turbidity level. Turbidity had a minor effect on time to prey capture, increasing from an average of 30 seconds at a turbidity level of 2 NTUs to 55 seconds at 40 NTUs. Overall, turbidity level explained approximately 2 of the variation in the time it took a turtle to locate a prey item. These results contrast sharply with a nearly identical study, which showed that turbidity explained 70 and 90 of the variation in drift-feeding fish reactive distance and prey capture success respectively, and that a turbidity of only 910 NTUs reduced fish foraging performance by 50. We suggest that resilience to turbidity effects on foraging proficiency among generalist species may be important to understanding their persistence in more degraded aquatic environments compared to more specialized species. ? 2010 by the American Society of Ichthyologists and Herpetologists.},
	number = {3},
	journal = {Copeia},
	author = {Grosse, A.M. and Sterrett, S.C. and Maerz, J.C.},
	year = {2010},
	pages = {463--467},
}

The effect of increased turbidity levels on aquatic organisms is an increasing concern for aquatic biologists. Recent studies show reduced foraging efficiency of drift-feeding fish species, which are highly visual predators, with increasing water turbidity. Similar to fish, many aquatic turtle species are highly visual aquatic predators that may be negatively affected by increasing water turbidity. We used Eastern Painted Turtles (Chrysemys picta) to test the hypothesis that increasing water turbidity would decrease prey capture efficiency. We classically conditioned eight C. picta to search for a food item when presented with a novel stimulus, and then measured the time it took each turtle to find a prey item under a range of 26 turbidity levels (?40 nephelometric turbidity units, NTUs) presented in a random order. All turtles were successfully trained within 29 days to search for the food item when presented with the stimulus. Turbidity had no effect on the probability of successful prey capture. Turtles located the prey item in 97 of trials regardless of turbidity level. Turbidity had a minor effect on time to prey capture, increasing from an average of 30 seconds at a turbidity level of 2 NTUs to 55 seconds at 40 NTUs. Overall, turbidity level explained approximately 2 of the variation in the time it took a turtle to locate a prey item. These results contrast sharply with a nearly identical study, which showed that turbidity explained 70 and 90 of the variation in drift-feeding fish reactive distance and prey capture success respectively, and that a turbidity of only 910 NTUs reduced fish foraging performance by 50. We suggest that resilience to turbidity effects on foraging proficiency among generalist species may be important to understanding their persistence in more degraded aquatic environments compared to more specialized species. ? 2010 by the American Society of Ichthyologists and Herpetologists.

@article{maerz_does_2010,
	title = {Does detritus quality predict the effect of native and non-native plants on the performance of larval amphibians?},
	volume = {55},
	copyright = {All rights reserved},
	doi = {10.1111/j.1365-2427.2010.02404.x},
	abstract = {The lack of consistent differences between the traits of native and non-native plant species makes it difficult to make general predictions about the ecological impact of invasive plants; however, the increasing number of non-native plants in many habitats makes the assessment of the impact of each individual species impracticable. General knowledge about how specific plant traits are linked to their effects on communities or ecosystems may be more useful for predicting the effect of plant invasions. Specifically, we hypothesised that higher carbon-to-nitrogen ratio (C:N) and percent lignin in plant detritus would reduce the rate of development and total mass at metamorphosis of tadpoles, resulting in lower metamorph production (total fresh biomass) and amphibian species richness. To test these hypotheses, we raised five species of tadpoles in mesocosms containing senescent leaves of three common native and three common non-native wetland plants that varied in C:N ratio and \% lignin. Leaf mass loss, total metamorph production and the number of species that metamorphosed declined as a function of increasing C:N ratio of plant leaves. Plant lignin content was not related to the production of metamorphs or the number of species that metamorphosed. The percentage of wood frog (Lithobates sylvaticus) and American toad (Anaxyrus americanus) tadpoles reaching metamorphosis declined as a function of increasing plant C:N ratio. Mean time to metamorphosis increased and mean mass at metamorphosis declined as a function of increasing plant C:N ratio. Tadpole performance and metamorph diversity and production (biomass) were similar between native and non-native plant species with similar C:N ratio in leaves. Percent lignin was not a significant predictor of tadpole performance. Our results show that the impact of a plant invasion on tadpole performance could depend on differences between the quality of the detritus produced by the invading species and that of the native species it replaces. We suggest that plant community changes that lead to dominance by more recalcitrant plant species (those with higher leaf C:N ratio) may negatively affect amphibian populations. ? 2010 Blackwell Publishing Ltd.},
	number = {8},
	journal = {Freshwater Biology},
	author = {Maerz, J.C. and Cohen, J.S. and Blossey, B.},
	year = {2010},
	keywords = {C:N ratio, Detritus, Invasive plants, [Amphibians},
	pages = {1694--1704},
}

The lack of consistent differences between the traits of native and non-native plant species makes it difficult to make general predictions about the ecological impact of invasive plants; however, the increasing number of non-native plants in many habitats makes the assessment of the impact of each individual species impracticable. General knowledge about how specific plant traits are linked to their effects on communities or ecosystems may be more useful for predicting the effect of plant invasions. Specifically, we hypothesised that higher carbon-to-nitrogen ratio (C:N) and percent lignin in plant detritus would reduce the rate of development and total mass at metamorphosis of tadpoles, resulting in lower metamorph production (total fresh biomass) and amphibian species richness. To test these hypotheses, we raised five species of tadpoles in mesocosms containing senescent leaves of three common native and three common non-native wetland plants that varied in C:N ratio and % lignin. Leaf mass loss, total metamorph production and the number of species that metamorphosed declined as a function of increasing C:N ratio of plant leaves. Plant lignin content was not related to the production of metamorphs or the number of species that metamorphosed. The percentage of wood frog (Lithobates sylvaticus) and American toad (Anaxyrus americanus) tadpoles reaching metamorphosis declined as a function of increasing plant C:N ratio. Mean time to metamorphosis increased and mean mass at metamorphosis declined as a function of increasing plant C:N ratio. Tadpole performance and metamorph diversity and production (biomass) were similar between native and non-native plant species with similar C:N ratio in leaves. Percent lignin was not a significant predictor of tadpole performance. Our results show that the impact of a plant invasion on tadpole performance could depend on differences between the quality of the detritus produced by the invading species and that of the native species it replaces. We suggest that plant community changes that lead to dominance by more recalcitrant plant species (those with higher leaf C:N ratio) may negatively affect amphibian populations. ? 2010 Blackwell Publishing Ltd.

@article{milanovich_projected_2010,
	title = {Projected loss of a salamander diversity hotspot as a consequence of projected global climate change},
	volume = {5},
	copyright = {All rights reserved},
	doi = {10.1371/journal.pone.0012189},
	abstract = {Background: Significant shifts in climate are considered a threat to plants and animals with significant physiological limitations and limited dispersal abilities. The southern Appalachian Mountains are a global hotspot for plethodontid salamander diversity. Plethodontids are lungless ectotherms, so their ecology is strongly governed by temperature and precipitation. Many plethodontid species in southern Appalachia exist in high elevation habitats that may be at or near their thermal maxima, and may also have limited dispersal abilities across warmer valley bottoms. Methodology/Principal Findings: We used a maximum-entropy approach (program Maxent) to model the suitable climatic habitat of 41 plethodontid salamander species inhabiting the Appalachian Highlands region (33 individual species and eight species included within two species complexes). We evaluated the relative change in suitable climatic habitat for these species in the Appalachian Highlands from the current climate to the years 2020, 2050, and 2080, using both the HADCM3 and the CGCM3 models, each under low and high CO2 scenarios, and using two-model thresholds levels (relative suitability thresholds for determining suitable/unsuitable range), for a total of 8 scenarios per species. Conclusion/Significance: While models differed slightly, every scenario projected significant declines in suitable habitat within the Appalachian Highlands as early as 2020. Species with more southern ranges and with smaller ranges had larger projected habitat loss. Despite significant differences in projected precipitation changes to the region, projections did not differ significantly between global circulation models. CO2 emissions scenario and model threshold had small effects on projected habitat loss by 2020, but did not affect longer-term projections. Results of this study indicate that choice of model threshold and CO2 emissions scenario affect short-term projected shifts in climatic distributions of species; however, these factors and choice of global circulation model have relatively small affects on what is significant projected loss of habitat for many salamander species that currently occupy the Appalachian Highlands. ? 2010 Milanovich et al.},
	number = {8},
	journal = {PLoS ONE},
	author = {Milanovich, J.R. and Peterman, W.E. and Nibbelink, N.P. and Maerz, J.C.},
	year = {2010},
	pages = {e12189},
}

Background: Significant shifts in climate are considered a threat to plants and animals with significant physiological limitations and limited dispersal abilities. The southern Appalachian Mountains are a global hotspot for plethodontid salamander diversity. Plethodontids are lungless ectotherms, so their ecology is strongly governed by temperature and precipitation. Many plethodontid species in southern Appalachia exist in high elevation habitats that may be at or near their thermal maxima, and may also have limited dispersal abilities across warmer valley bottoms. Methodology/Principal Findings: We used a maximum-entropy approach (program Maxent) to model the suitable climatic habitat of 41 plethodontid salamander species inhabiting the Appalachian Highlands region (33 individual species and eight species included within two species complexes). We evaluated the relative change in suitable climatic habitat for these species in the Appalachian Highlands from the current climate to the years 2020, 2050, and 2080, using both the HADCM3 and the CGCM3 models, each under low and high CO2 scenarios, and using two-model thresholds levels (relative suitability thresholds for determining suitable/unsuitable range), for a total of 8 scenarios per species. Conclusion/Significance: While models differed slightly, every scenario projected significant declines in suitable habitat within the Appalachian Highlands as early as 2020. Species with more southern ranges and with smaller ranges had larger projected habitat loss. Despite significant differences in projected precipitation changes to the region, projections did not differ significantly between global circulation models. CO2 emissions scenario and model threshold had small effects on projected habitat loss by 2020, but did not affect longer-term projections. Results of this study indicate that choice of model threshold and CO2 emissions scenario affect short-term projected shifts in climatic distributions of species; however, these factors and choice of global circulation model have relatively small affects on what is significant projected loss of habitat for many salamander species that currently occupy the Appalachian Highlands. ? 2010 Milanovich et al.

@article{ruiz_patterns_2010,
	title = {Patterns of development and abnormalities among tadpoles in a constructed wetland receiving treated wastewater},
	volume = {44},
	copyright = {All rights reserved},
	doi = {10.1021/es903785x},
	abstract = {Constructed wetlands are promoted for effectiveness at treating wastewater and potential value as wildlife habitat; however, wildlife performance studies in treated wastewater wetlands are limited. We used repeated surveys of larval amphibians along three wetland systems and four reference sites to test the hypothesis that bullfrog tadpoles exposed to direct inputs of treated wastewater develop slower, show a higher frequency of abnormalities, and are smaller at metamorphosis compared to tadpoles from reference ponds. Bullfrog tadpoles from wastewater wetlands were similar in size at metamorphosis compared to tadpoles from reference sites; however, they did show a much higher frequency of abnormalities including severe edema, scoliosis, and extreme calcinosis of soft tissues. Calcinosis was novel to the literature on amphibian abnormalities, the most frequent abnormality, and restricted exclusively to treatment wetlands. Within the constructed wetlands, tadpole development was slower and the frequency of scoliosis and calcinosis was higher in those cells receiving direct inputs of treated wastewater. Our results suggest that portions of constructed wetlands that directly receive treated wastewater may be poor amphibian habitat. ? 2010 American Chemical Society.},
	number = {13},
	journal = {Environmental Science and Technology},
	author = {Ruiz, A.M. and Maerz, J.C. and Davis, A.K. and Keel, M.K. and Ferreira, A.R. and Conroy, M.J. and Morris, L.A. and Fisk, A.T.},
	year = {2010},
	pages = {4862--4868},
}

Constructed wetlands are promoted for effectiveness at treating wastewater and potential value as wildlife habitat; however, wildlife performance studies in treated wastewater wetlands are limited. We used repeated surveys of larval amphibians along three wetland systems and four reference sites to test the hypothesis that bullfrog tadpoles exposed to direct inputs of treated wastewater develop slower, show a higher frequency of abnormalities, and are smaller at metamorphosis compared to tadpoles from reference ponds. Bullfrog tadpoles from wastewater wetlands were similar in size at metamorphosis compared to tadpoles from reference sites; however, they did show a much higher frequency of abnormalities including severe edema, scoliosis, and extreme calcinosis of soft tissues. Calcinosis was novel to the literature on amphibian abnormalities, the most frequent abnormality, and restricted exclusively to treatment wetlands. Within the constructed wetlands, tadpole development was slower and the frequency of scoliosis and calcinosis was higher in those cells receiving direct inputs of treated wastewater. Our results suggest that portions of constructed wetlands that directly receive treated wastewater may be poor amphibian habitat. ? 2010 American Chemical Society.

@article{sterrett_assessment_2010,
	title = {An assessment of two methods for sampling river turtle assemblages},
	volume = {5},
	copyright = {All rights reserved},
	abstract = {We compared the effectiveness of baited hoop traps and effort-managed snorkel surveys for detecting freshwater turtle species within two streams in southwestern Georgia, USA. Snorkel surveys provided the highest detection probability for the four most frequently captured species. We captured the Barbour's Map Turtle (Graptemys barbouri), a threatened species in the southeastern U.S., 90\% of the time by snorkeling; whereas, we captured the Yellowbellied Slider (Trachemys scripta) 88\% of the time by hoop traps. We captured adults and juveniles with both methods, with the exception of juvenile Loggerhead Musk Turtles (Sternotherus minor), which we caught only via snorkeling. The two methods captured turtles of similar sizes. Seasonal and physical constraints can affect visibility and access to capture locations, limiting snorkeling sessions. We recommend use of both techniques to capture a range of sexes, sizes, and species of turtles in Coastal Plain streams. However, species-specific surveys may benefit by lower effort with the use of only one method.},
	number = {3},
	journal = {Herpetological Conservation and Biology},
	author = {Sterrett, S.C. and Smith, L.L. and Schweitzer, S.H. and Maerz, J.C.},
	year = {2010},
	keywords = {Detection probability, Georgia, Gr, [Coastal plain},
	pages = {490--497},
}

We compared the effectiveness of baited hoop traps and effort-managed snorkel surveys for detecting freshwater turtle species within two streams in southwestern Georgia, USA. Snorkel surveys provided the highest detection probability for the four most frequently captured species. We captured the Barbour's Map Turtle (Graptemys barbouri), a threatened species in the southeastern U.S., 90% of the time by snorkeling; whereas, we captured the Yellowbellied Slider (Trachemys scripta) 88% of the time by hoop traps. We captured adults and juveniles with both methods, with the exception of juvenile Loggerhead Musk Turtles (Sternotherus minor), which we caught only via snorkeling. The two methods captured turtles of similar sizes. Seasonal and physical constraints can affect visibility and access to capture locations, limiting snorkeling sessions. We recommend use of both techniques to capture a range of sexes, sizes, and species of turtles in Coastal Plain streams. However, species-specific surveys may benefit by lower effort with the use of only one method.

@article{strickland_grass_2010,
	title = {Grass invasion of a hardwood forest is associated with declines in belowground carbon pools},
	volume = {16},
	copyright = {All rights reserved},
	doi = {10.1111/j.1365-2486.2009.02042.x},
	abstract = {Invasive plant species affect a range of ecosystem processes but their impact on belowground carbon (C) pools is relatively unexplored. This is particularly true for grass invasions of forested ecosystems. Such invasions may alter both the quantity and quality of forest floor inputs. Dependent on both, two theories, 'priming' and 'preferential substrate utilization', suggest these changes may decrease, increase, or leave unchanged native plant-derived soil C. Decreases are expected under 'priming' theory due to increased soil microbial activity. Under 'preferential substrate utilization', either an increase or no change is expected because the invasive plant's inputs are used by the microbial community instead of soil C. Here, we examine how Microstegium vimineum affects belowground C-cycling in a southeastern US forest. Following predictions of priming theory, M. vimineum's presence is associated with decreases in native-derived, C pools. For example, in September 2006 M. vimineum is associated with 24\%, 34\%, 36\%, and 72\% declines in total organic, particulate organic matter, mineralizable (a measure of microbially-available C), and microbial biomass C, respectively. Soil C derived from M. vimineum does not compensate for these decreases, meaning that the sum of native- plus invasive-derived C pools is smaller than native-derived pools in uninvaded plots. Supporting our inferences that C-cycling accelerates under invasion, the microbial community is more active per unit biomass: added 13C-glucose is respired more rapidly in invaded plots. Our work suggests that this invader may accelerate C-cycling in forest soils and deplete C stocks. The paucity of studies investigating impacts of grass invasion on C-cycling in forests highlights the need to study further M. vimineum and other invasive grasses to assess their impacts on C sink strength and forest fertility. ? 2009 Blackwell Publishing Ltd.},
	number = {4},
	journal = {Global Change Biology},
	author = {Strickland, M.S. and Devore, J.L. and Maerz, J.C. and Bradford, M.A.},
	year = {2010},
	keywords = {Carbon sequestration, Carbon sink, [Annual grass},
	pages = {1338--1350},
}

Invasive plant species affect a range of ecosystem processes but their impact on belowground carbon (C) pools is relatively unexplored. This is particularly true for grass invasions of forested ecosystems. Such invasions may alter both the quantity and quality of forest floor inputs. Dependent on both, two theories, 'priming' and 'preferential substrate utilization', suggest these changes may decrease, increase, or leave unchanged native plant-derived soil C. Decreases are expected under 'priming' theory due to increased soil microbial activity. Under 'preferential substrate utilization', either an increase or no change is expected because the invasive plant's inputs are used by the microbial community instead of soil C. Here, we examine how Microstegium vimineum affects belowground C-cycling in a southeastern US forest. Following predictions of priming theory, M. vimineum's presence is associated with decreases in native-derived, C pools. For example, in September 2006 M. vimineum is associated with 24%, 34%, 36%, and 72% declines in total organic, particulate organic matter, mineralizable (a measure of microbially-available C), and microbial biomass C, respectively. Soil C derived from M. vimineum does not compensate for these decreases, meaning that the sum of native- plus invasive-derived C pools is smaller than native-derived pools in uninvaded plots. Supporting our inferences that C-cycling accelerates under invasion, the microbial community is more active per unit biomass: added 13C-glucose is respired more rapidly in invaded plots. Our work suggests that this invader may accelerate C-cycling in forest soils and deplete C stocks. The paucity of studies investigating impacts of grass invasion on C-cycling in forests highlights the need to study further M. vimineum and other invasive grasses to assess their impacts on C sink strength and forest fertility. ? 2009 Blackwell Publishing Ltd.

@article{thigpen_effectiveness_2010,
	title = {Effectiveness of using burlap bands to sample arboreal green salamander populations in the blue ridge mountains of {Georgia} and {North} {Carolina}},
	volume = {41},
	copyright = {All rights reserved},
	number = {2},
	journal = {Herpetological Review},
	author = {Thigpen, T.F. and Humphries, W.J. and Maerz, J.C.},
	year = {2010},
	pages = {159--162},
}

@article{keel_soft-tissue_2010,
	title = {Soft-tissue mineralization of bullfrog larvae ({Rana} catesbeiana) at a wastewater treatment facility},
	volume = {22},
	copyright = {All rights reserved},
	abstract = {Bullfrog tadpoles (Rana catesbeiana) from a wastewater treatment facility were identified with severe lesions consisting of large, up to 1-cm in diameter, mineralized nodules protruding from the tail or gular region. Sectioning of formalin-fixed specimens revealed more extensive mineralization involving the vertebrae or muscles of the head and tail. Nodules examined microscopically were not associated with parasitic or infectious agents. Large nodules consisted of mineralized aggregates surrounded by a margin of granulomatous inflammation. Individual connective-tissue fibers and muscle cells were mineralized at some foci. The nodules consisted entirely of calcium phosphate, and the lesions appeared to be novel. Total serumcalcium concentrations of tadpoles and calcium concentrations in water samples did not differ significantly with increasing distance from the discharge site. Affected tadpoles had elevated cholecalciferol (25-OHvitamin D3) levels. Effluent from this wastewater treatment facility is divided into 3 streams, each passing through a separate series of wetlands allowing for replicated evaluation of tadpoles with increasing distance from the proximate inputs of treated wastewater. The prevalence of lesions was correlated with proximity of cells to the initial wastewater discharge site, and 28.5\% of bullfrog larvae in the first cells had lesions. None were affected in the fifth cells. Southern leopard frog larvae (Rana sphenocephala), the only other species affected, had a much lower prevalence of lesions ({\textless}1\%) than bullfrog tadpoles and were only affected in the first cells. To date, the primary cause of elevated cholecalciferol is undetermined, but it appears to be remediated by passage of water through the wetlands.},
	number = {4},
	journal = {Journal of Veterinary Diagnostic Investigation},
	author = {Keel, M.K. and Ruiz, A.M. and Fisk, A.T. and Rumbeiha, W.K. and Davis, A.K. and Maerz, J.C.},
	year = {2010},
	keywords = {Cholecalciferol, Endocrine, Frogs, Min, [Amphibian},
}

Bullfrog tadpoles (Rana catesbeiana) from a wastewater treatment facility were identified with severe lesions consisting of large, up to 1-cm in diameter, mineralized nodules protruding from the tail or gular region. Sectioning of formalin-fixed specimens revealed more extensive mineralization involving the vertebrae or muscles of the head and tail. Nodules examined microscopically were not associated with parasitic or infectious agents. Large nodules consisted of mineralized aggregates surrounded by a margin of granulomatous inflammation. Individual connective-tissue fibers and muscle cells were mineralized at some foci. The nodules consisted entirely of calcium phosphate, and the lesions appeared to be novel. Total serumcalcium concentrations of tadpoles and calcium concentrations in water samples did not differ significantly with increasing distance from the discharge site. Affected tadpoles had elevated cholecalciferol (25-OHvitamin D3) levels. Effluent from this wastewater treatment facility is divided into 3 streams, each passing through a separate series of wetlands allowing for replicated evaluation of tadpoles with increasing distance from the proximate inputs of treated wastewater. The prevalence of lesions was correlated with proximity of cells to the initial wastewater discharge site, and 28.5% of bullfrog larvae in the first cells had lesions. None were affected in the fifth cells. Southern leopard frog larvae (Rana sphenocephala), the only other species affected, had a much lower prevalence of lesions (\textless1%) than bullfrog tadpoles and were only affected in the first cells. To date, the primary cause of elevated cholecalciferol is undetermined, but it appears to be remediated by passage of water through the wetlands.

@article{camp_new_2009,
	title = {A new genus and species of lungless salamander (family {Plethodontidae}) from the {Appalachian} highlands of the south-eastern {United} {States}},
	volume = {279},
	copyright = {All rights reserved},
	doi = {10.1111/j.1469-7998.2009.00593.x},
	abstract = {We describe a striking new species of the lungless salamander family Plethodontidae from the Appalachian foothills of northern Georgia, USA. This miniature species, c. 25-26 mm (adult standard length), is so distinctive genetically and morphologically that we erect a new genus, the first new genus of amphibian described from the US in nearly 50 years. It is unique among plethodontids from eastern North America in displaying sexual colour dimorphism. Although certain miniaturized plethodontids exhibit a reduced number (four) of digits on the pes, this species possesses a full complement of five toes. A plethodontid phylogeny derived from mitochondrial and nuclear DNA sequences places it in the tribe Spelerpini as the sister taxon to Eurycea. Genetic divergence between the new species and Eurycea for the nuclear gene Rag-1 (4.7\%) is among the higher levels observed between long-established spelerpine genera (2.6-5.3\%). This new form appears to be rare and is of immediate conservation concern. ? 2009 The Zoological Society of London.},
	number = {1},
	journal = {Journal of Zoology},
	author = {Camp, C.D. and Peterman, W.E. and Milanovich, J.R. and Lamb, T. and Maerz, J.C. and Wake, D.B.},
	year = {2009},
	keywords = {Miniaturization, New genus, New speci, [Dimorphism},
	pages = {86--94},
}

We describe a striking new species of the lungless salamander family Plethodontidae from the Appalachian foothills of northern Georgia, USA. This miniature species, c. 25-26 mm (adult standard length), is so distinctive genetically and morphologically that we erect a new genus, the first new genus of amphibian described from the US in nearly 50 years. It is unique among plethodontids from eastern North America in displaying sexual colour dimorphism. Although certain miniaturized plethodontids exhibit a reduced number (four) of digits on the pes, this species possesses a full complement of five toes. A plethodontid phylogeny derived from mitochondrial and nuclear DNA sequences places it in the tribe Spelerpini as the sister taxon to Eurycea. Genetic divergence between the new species and Eurycea for the nuclear gene Rag-1 (4.7%) is among the higher levels observed between long-established spelerpine genera (2.6-5.3%). This new form appears to be rare and is of immediate conservation concern. ? 2009 The Zoological Society of London.

@article{davis_new_2009,
	title = {New findings from an old pathogen: intraerythrocytic bacteria (family anaplasmatacea) in red-backed salamanders plethodon cinereus},
	volume = {6},
	copyright = {All rights reserved},
	doi = {10.1007/s10393-009-0250-0},
	abstract = {During a recent study of red-backed salamanders (Plethodon cinereus), we discovered an intra-erythrocytic organism typified by violet-staining, intracellular inclusions, consistent with descriptions of Cytamoeba or Aegyptianella (bacteria). Here we characterize its taxonomic status using molecular techniques and ask basic questions about its nature. Blood smears from 102 salamanders were examined from Pennsylvania, New York, and Virginia to determine prevalence, and whole blood from several infected animals was tested using a PCR which targets the 16S rRNA gene of bacteria. Phylogenetic analysis of partial 16S rRNA gene sequence (1201 bp) indicated this organism was in the order Rickettsiales and is likely a member of the family Anaplasmatacea. The organism differed from currently described taxa and was clearly differentiated from Aegyptianella pullorum of birds and "Candidatus Hemobacterium ranarum" (formally A. ranarum) of frogs. Of all salamanders, 17 (16.7\%) were infected and these were significantly larger (snout-vent length) and had higher body condition scores than uninfected ones, and males were more likely to be infected than females. Erythrocytes affected by the pathogen were 5\% larger than unaffected ones, but otherwise similar in morphology. Infected animals tended to have a greater number of circulating white blood cells, based on estimates from smears, indicating a nonspecific response to the pathogen by the innate immune system. Given its phylogenetic position, this pathogen is likely transmitted by an arthropod vector, and the male-biased prevalence strongly implicates trombiculid mites, which also live in leaf litter and affect male salamanders more so than females. ? 2010 International Association for Ecology and Health.},
	number = {2},
	journal = {EcoHealth},
	author = {Davis, A.K. and DeVore, J.L. and Milanovich, J.R. and Cecala, K. and Maerz, J.C. and Yabsley, M.J.},
	year = {2009},
	keywords = {Anaplasmatacea, Cytamoeba, Plethod, [Aegyptianella},
	pages = {219--228},
}

During a recent study of red-backed salamanders (Plethodon cinereus), we discovered an intra-erythrocytic organism typified by violet-staining, intracellular inclusions, consistent with descriptions of Cytamoeba or Aegyptianella (bacteria). Here we characterize its taxonomic status using molecular techniques and ask basic questions about its nature. Blood smears from 102 salamanders were examined from Pennsylvania, New York, and Virginia to determine prevalence, and whole blood from several infected animals was tested using a PCR which targets the 16S rRNA gene of bacteria. Phylogenetic analysis of partial 16S rRNA gene sequence (1201 bp) indicated this organism was in the order Rickettsiales and is likely a member of the family Anaplasmatacea. The organism differed from currently described taxa and was clearly differentiated from Aegyptianella pullorum of birds and "Candidatus Hemobacterium ranarum" (formally A. ranarum) of frogs. Of all salamanders, 17 (16.7%) were infected and these were significantly larger (snout-vent length) and had higher body condition scores than uninfected ones, and males were more likely to be infected than females. Erythrocytes affected by the pathogen were 5% larger than unaffected ones, but otherwise similar in morphology. Infected animals tended to have a greater number of circulating white blood cells, based on estimates from smears, indicating a nonspecific response to the pathogen by the innate immune system. Given its phylogenetic position, this pathogen is likely transmitted by an arthropod vector, and the male-biased prevalence strongly implicates trombiculid mites, which also live in leaf litter and affect male salamanders more so than females. ? 2010 International Association for Ecology and Health.

@article{davis_investigation_2009,
	title = {An investigation of factors influencing erythrocyte morphology of red-backed salamanders ({Plethodon} cinereus)},
	volume = {59},
	copyright = {All rights reserved},
	doi = {10.1163/157075609X437718},
	abstract = {Amphibians have long been known to display wide variation in erythrocyte morphology across species, but within species there has been little attention given to individual variation in red blood cell morphology. We captured 49 red-backed salamanders (Plethodon cinereus) from central Pennsylvania, USA and used image analysis procedures to measure erythrocyte morphology (size and shape) on blood smears made from all individuals. We then statistically examined whether variation in snout-vent-length, sex, tail loss, or capture location influenced these cell variables. Only snout-vent-length affected erythrocyte size and shape, with increasing body sizes associated with increasing cell areas and increasingly rounder cells. Further, erythrocyte shape was also associated with a measure of body condition that was corrected for body size, such that individuals with high body condition scores had rounder cells. Given the oxygen-carrying role of erythrocytes in all vertebrates, we suspect this discovery is related to size-related changes in oxygen demand, since total oxygen consumption increases with body size in an allometric manner. While our results warrant further investigation to understand the mechanism, the association we found between cell roundness and both body size and condition nevertheless indicates this parameter could be used to assess the health state of plethodontid salamanders in future research, provided non-destructive sampling is employed. Our results also underscore the value of hematological investigations in the study of animal biology. ? 2009 Koninklijke Brill NV, Leiden.},
	number = {2},
	journal = {Animal Biology},
	author = {Davis, A.K. and Milanovich, J.R. and Devore, J.L. and Maerz, J.C.},
	year = {2009},
	keywords = {Erythrocyte morphology, Image analysis, [Body size},
	pages = {201--209},
}

Amphibians have long been known to display wide variation in erythrocyte morphology across species, but within species there has been little attention given to individual variation in red blood cell morphology. We captured 49 red-backed salamanders (Plethodon cinereus) from central Pennsylvania, USA and used image analysis procedures to measure erythrocyte morphology (size and shape) on blood smears made from all individuals. We then statistically examined whether variation in snout-vent-length, sex, tail loss, or capture location influenced these cell variables. Only snout-vent-length affected erythrocyte size and shape, with increasing body sizes associated with increasing cell areas and increasingly rounder cells. Further, erythrocyte shape was also associated with a measure of body condition that was corrected for body size, such that individuals with high body condition scores had rounder cells. Given the oxygen-carrying role of erythrocytes in all vertebrates, we suspect this discovery is related to size-related changes in oxygen demand, since total oxygen consumption increases with body size in an allometric manner. While our results warrant further investigation to understand the mechanism, the association we found between cell roundness and both body size and condition nevertheless indicates this parameter could be used to assess the health state of plethodontid salamanders in future research, provided non-destructive sampling is employed. Our results also underscore the value of hematological investigations in the study of animal biology. ? 2009 Koninklijke Brill NV, Leiden.

@article{de_wan_using_2009,
	title = {Using occupancy models of forest breeding birds to prioritize conservation planning},
	volume = {142},
	copyright = {All rights reserved},
	doi = {10.1016/j.biocon.2008.12.032},
	abstract = {As urban development continues to encroach on the natural and rural landscape, land-use planners struggle to identify high priority conservation areas for protection. Although knowing where urban-sensitive species may be occurring on the landscape would facilitate conservation planning, research efforts are often not sufficiently designed to make quality predictions at unknown locations. Recent advances in occupancy modeling allow for more precise estimates of occupancy by accounting for differences in detectability. We applied these techniques to produce robust estimates of habitat occupancy for a subset of forest breeding birds, a group that has been shown to be sensitive to urbanization, in a rapidly urbanizing yet biological diverse region of New York State. We found that detection probability ranged widely across species, from 0.05 to 0.8. Our models suggest that detection probability declined with increasing forest fragmentation. We also found that the probability of occupancy of forest breeding birds is negatively influenced by increasing perimeter-area ratio of forest fragments and urbanization in the surrounding habitat matrix. We capitalized on our random sampling design to produce spatially explicit models that predict high priority conservation areas across the entire region, where interior-species were most likely to occur. Finally, we use our predictive maps to demonstrate how a strict sampling design coupled with occupancy modeling can be a valuable tool for prioritizing biodiversity conservation in land-use planning. ? 2009 Elsevier Ltd.},
	number = {5},
	journal = {Biological Conservation},
	author = {De Wan, A.A. and Sullivan, P.J. and Lembo, A.J. and Smith, C.R. and Maerz, J.C. and Lassoie, J.P. and Richmond, M.E.},
	year = {2009},
	keywords = {Conservation planning, Detection pr, [Biodiversity},
	pages = {982--991},
}

As urban development continues to encroach on the natural and rural landscape, land-use planners struggle to identify high priority conservation areas for protection. Although knowing where urban-sensitive species may be occurring on the landscape would facilitate conservation planning, research efforts are often not sufficiently designed to make quality predictions at unknown locations. Recent advances in occupancy modeling allow for more precise estimates of occupancy by accounting for differences in detectability. We applied these techniques to produce robust estimates of habitat occupancy for a subset of forest breeding birds, a group that has been shown to be sensitive to urbanization, in a rapidly urbanizing yet biological diverse region of New York State. We found that detection probability ranged widely across species, from 0.05 to 0.8. Our models suggest that detection probability declined with increasing forest fragmentation. We also found that the probability of occupancy of forest breeding birds is negatively influenced by increasing perimeter-area ratio of forest fragments and urbanization in the surrounding habitat matrix. We capitalized on our random sampling design to produce spatially explicit models that predict high priority conservation areas across the entire region, where interior-species were most likely to occur. Finally, we use our predictive maps to demonstrate how a strict sampling design coupled with occupancy modeling can be a valuable tool for prioritizing biodiversity conservation in land-use planning. ? 2009 Elsevier Ltd.

@article{fisk_metabolic_2009,
	title = {Metabolic turnover rates of carbon and nitrogen stable isotopes in captive juvenile snakes},
	volume = {23},
	copyright = {All rights reserved},
	abstract = {Metabolic turnover rates (m) of delta(15)N and delta(13)C were assessed in different tissues of newly hatched captive-raised corn snakes (Elaphe guttata guttata) fed maintenance diets consisting of earthworms (Eisenia foetida) that varied substantially in delta(15)N (by 644 per thousand) and delta(13)C (by 5.0 per thousand). Three treatments were used during this 144 day experiment that consisted of the same diet throughout (control), shifting from a depleted to an enriched stable isotope signature diet (uptake), and shifting from an enriched to depleted stable isotope signature diet (elimination). Values of delta(13)C in the liver, blood, and muscle of the control snakes reached equilibrium with and were, respectively, 1.73, 2.25 and 2.29 greater than in their diet, this increase is called an isotopic discrimination factor (Deltadelta(13)C = delta(13)C(snake) - delta(13)C(food)). Values of delta(15)N in snake tissues did not achieve equilibrium with the diets in any of the exposures and thus Delta(15)N could not be estimated. Values of metabolic turnover rates (m) for delta(13)C and delta(15)N were greater in liver than in muscle and blood, which were similar, and relative results remained the same if the fraction of (15)N and (13)C were modeled. Although caution is warranted because equilibrium values of stable isotopes in the snakes were not achieved, values of m were greater for delta(13)C than delta(15)N, resulting in shorter times to dietary equilibrium for delta(13)C upon a diet shift, and for both stable isotopes in all tissues, greater during an elimination than in an uptake shift in diet stable isotope signature. Multiple explanations for the observed differences between uptake and elimination shifts raise new questions about the relationship between animal and diet stable isotope concentrations. Based on this study, interpretation of feeding ecology using stable isotopes is highly dependent on the kind of stable isotope, tissue, direction of diet switch (uptake versus elimination), and the growth rate of the animal.},
	number = {2},
	journal = {Rapid Communications in Mass Spectrometry},
	author = {Fisk, Aaron T. and Sash, Kim and Maerz, John and Palmer, William and Carroll, John P. and MacNeil, M. Aaron},
	year = {2009},
	pages = {319--326},
}

Metabolic turnover rates (m) of delta(15)N and delta(13)C were assessed in different tissues of newly hatched captive-raised corn snakes (Elaphe guttata guttata) fed maintenance diets consisting of earthworms (Eisenia foetida) that varied substantially in delta(15)N (by 644 per thousand) and delta(13)C (by 5.0 per thousand). Three treatments were used during this 144 day experiment that consisted of the same diet throughout (control), shifting from a depleted to an enriched stable isotope signature diet (uptake), and shifting from an enriched to depleted stable isotope signature diet (elimination). Values of delta(13)C in the liver, blood, and muscle of the control snakes reached equilibrium with and were, respectively, 1.73, 2.25 and 2.29 greater than in their diet, this increase is called an isotopic discrimination factor (Deltadelta(13)C = delta(13)C(snake) - delta(13)C(food)). Values of delta(15)N in snake tissues did not achieve equilibrium with the diets in any of the exposures and thus Delta(15)N could not be estimated. Values of metabolic turnover rates (m) for delta(13)C and delta(15)N were greater in liver than in muscle and blood, which were similar, and relative results remained the same if the fraction of (15)N and (13)C were modeled. Although caution is warranted because equilibrium values of stable isotopes in the snakes were not achieved, values of m were greater for delta(13)C than delta(15)N, resulting in shorter times to dietary equilibrium for delta(13)C upon a diet shift, and for both stable isotopes in all tissues, greater during an elimination than in an uptake shift in diet stable isotope signature. Multiple explanations for the observed differences between uptake and elimination shifts raise new questions about the relationship between animal and diet stable isotope concentrations. Based on this study, interpretation of feeding ecology using stable isotopes is highly dependent on the kind of stable isotope, tissue, direction of diet switch (uptake versus elimination), and the growth rate of the animal.

@article{grosse_diamondback_2009,
	title = {Diamondback terrapin mortality in crab pots in a {Georgia} tidal marsh},
	volume = {8},
	copyright = {All rights reserved},
	doi = {10.2744/CCB-0729.1},
	abstract = {Recreational and commercial crab pots are considered major threats contributing to recent declines in diamondback terrapin populations. In a single Georgia (USA) tidal marsh, 133 diamondback terrapin (Malaclemys terrapin centrata) carcasses were observed in abandoned crab pots, consisting of more than double the remaining estimated population. We suggest that the potential for just a few neglected or abandoned crab pots to significantly deplete a terrapin population makes enforcement of explicit soak laws and implementation of a derelict crab-pot removal program a priority for conservation of diamondback terrapins in Georgia. ? 2009 Chelonian Research Foundation.},
	number = {1},
	journal = {Chelonian Conservation and Biology},
	author = {Grosse, A.M. and Van Daniel Dijk, J. and Holcomb, K.L. and Maerz, J.C.},
	year = {2009},
	pages = {98--100},
}

Recreational and commercial crab pots are considered major threats contributing to recent declines in diamondback terrapin populations. In a single Georgia (USA) tidal marsh, 133 diamondback terrapin (Malaclemys terrapin centrata) carcasses were observed in abandoned crab pots, consisting of more than double the remaining estimated population. We suggest that the potential for just a few neglected or abandoned crab pots to significantly deplete a terrapin population makes enforcement of explicit soak laws and implementation of a derelict crab-pot removal program a priority for conservation of diamondback terrapins in Georgia. ? 2009 Chelonian Research Foundation.

@article{nowakowski_estimation_2009,
	title = {Estimation of larval stream salamander densities in three proximate streams in the {Georgia} piedmont},
	volume = {43},
	copyright = {All rights reserved},
	abstract = {Despite decades of research, there is still little known about the natural abundances and ecological importance of stream salamander larvae in eastern North America. Widely used methods for sampling larvae and estimating population densities can be significantly biased, which may have implications for monitoring efforts and studies addressing the effects of salamanders on stream processes such as nutrient dynamics. We compared the efficacy of two methods of capture, passive leaf litter trapping and dip netting, and performed mark–recapture (M-R) on larvae occurring in three adjacent streams. There was a significant size bias associated with at least one of our capture methods. Leaf litter traps captured a higher proportion of larger individuals (.15 mm SVL), whereas dip netting yielded a greater proportion of the smaller size class (\#15 mm). Density estimates were 1–2 orders of magnitude greater than estimates provided by other studies; however, count indices were comparable to those previously reported. Density estimates from M-R ranged from 23–169 salamander larvae per m2, which was remarkably consistent with estimates of 75–137 larvae per m2 from a contemporaneous study using nearly identical methodology in Appalachian streams in North Carolina. The coefficient of variation for mean density estimates generated from M-R was greater than that detected with count data, indicating that the use of replicated counts without adjustment for detection may be less effective for measuring spatial and temporal variation in larval stream salamander numbers.},
	journal = {Journal of Herpetology},
	author = {Nowakowski, A Justin and Maerz, John C},
	year = {2009},
	keywords = {Georgia, abundance, amphibian, larval salamander, mark-recapture, stream},
	pages = {503--509},
}

Despite decades of research, there is still little known about the natural abundances and ecological importance of stream salamander larvae in eastern North America. Widely used methods for sampling larvae and estimating population densities can be significantly biased, which may have implications for monitoring efforts and studies addressing the effects of salamanders on stream processes such as nutrient dynamics. We compared the efficacy of two methods of capture, passive leaf litter trapping and dip netting, and performed mark–recapture (M-R) on larvae occurring in three adjacent streams. There was a significant size bias associated with at least one of our capture methods. Leaf litter traps captured a higher proportion of larger individuals (.15 mm SVL), whereas dip netting yielded a greater proportion of the smaller size class (#15 mm). Density estimates were 1–2 orders of magnitude greater than estimates provided by other studies; however, count indices were comparable to those previously reported. Density estimates from M-R ranged from 23–169 salamander larvae per m2, which was remarkably consistent with estimates of 75–137 larvae per m2 from a contemporaneous study using nearly identical methodology in Appalachian streams in North Carolina. The coefficient of variation for mean density estimates generated from M-R was greater than that detected with count data, indicating that the use of replicated counts without adjustment for detection may be less effective for measuring spatial and temporal variation in larval stream salamander numbers.

@article{davis_effects_2009,
	title = {Effects of larval density on hematological stress indices in salamanders},
	volume = {311},
	copyright = {All rights reserved},
	doi = {10.1002/jez.557},
	abstract = {In animals with complex life cycles, the quality of juvenile environments is important in shaping the longer-term fitness of individuals. Larval density is a major factor governing quality of larval environments in amphibians, with high densities leading to reduced growth rates, smaller size at metamorphosis, and potentially long-lasting postmetamorphic effects. A little-studied effect of larval density is its impact on physiological stress of postmetamorphic individuals. We used a hematological approach, involving counts of specific white blood cells types (neutrophils and lymphocytes) that covary with corticosterone, to estimate stress levels in recently metamorphosed spotted salamanders (Ambystoma maculatum) that were reared in three different larval densities in outdoor mesocosms. In replicated treatments consisting of 12, 25, or 50 larvae, survival was, as expected, lowest and size at metamorphosis smallest in the highest density mesocosms. In addition, surviving salamanders from high-density treatments had significantly higher neutrophil to lymphocyte ratios, indicative of high levels of stress hormones (corticosterone). This trend was not a result of density-related differences in body condition as these did not vary with density. Further, estimated stress levels were similar regardless of whether the salamanders metamorphosed early or late, suggesting that the density effect on stress is long-lasting even once realized density has been reduced through mortality or early metamorphosis. These results may be important in understanding amphibian population dynamics, since research on other vertebrate taxa demonstrates that high hematological stress indicators lead to reduced growth, survival, and increased disease susceptibility in vertebrate animals. ? 2009 Wiley-Liss, Inc.},
	number = {9},
	journal = {Journal of Experimental Zoology Part A: Ecological Genetics and Physiology},
	author = {Davis, A.K. and Maerz, J.C.},
	year = {2009},
}

In animals with complex life cycles, the quality of juvenile environments is important in shaping the longer-term fitness of individuals. Larval density is a major factor governing quality of larval environments in amphibians, with high densities leading to reduced growth rates, smaller size at metamorphosis, and potentially long-lasting postmetamorphic effects. A little-studied effect of larval density is its impact on physiological stress of postmetamorphic individuals. We used a hematological approach, involving counts of specific white blood cells types (neutrophils and lymphocytes) that covary with corticosterone, to estimate stress levels in recently metamorphosed spotted salamanders (Ambystoma maculatum) that were reared in three different larval densities in outdoor mesocosms. In replicated treatments consisting of 12, 25, or 50 larvae, survival was, as expected, lowest and size at metamorphosis smallest in the highest density mesocosms. In addition, surviving salamanders from high-density treatments had significantly higher neutrophil to lymphocyte ratios, indicative of high levels of stress hormones (corticosterone). This trend was not a result of density-related differences in body condition as these did not vary with density. Further, estimated stress levels were similar regardless of whether the salamanders metamorphosed early or late, suggesting that the density effect on stress is long-lasting even once realized density has been reduced through mortality or early metamorphosis. These results may be important in understanding amphibian population dynamics, since research on other vertebrate taxa demonstrates that high hematological stress indicators lead to reduced growth, survival, and increased disease susceptibility in vertebrate animals. ? 2009 Wiley-Liss, Inc.

@article{carter_beyond_2009,
	title = {Beyond the urban gradient: barriers and opportunities for timely studies of urbanization effects on aquatic ecosystems},
	volume = {28},
	copyright = {All rights reserved},
	abstract = {Many studies have shown that streams degrade in response to urbanization in the watershed. These studies often are based on use of biotic and abiotic variables to measure stream health across a gradient of land cover/land use. The results of these studies can be applied to other urban systems, but often fail to provide a mechanistic understanding of the urban impact, in part, because of the nature of the experimental design. We analyzed the advantages and disadvantages of using environmental gradient studies to further understanding of urban stream systems. We also evaluated alternative experimental design approaches, including best management practice monitoring, long-term watershed studies, paired- watershed studies, and before–after control–impact studies, which could be used to complement the gradient approach. We illustrate these theoretical discussions with an urban paired-watershed case study in the Etowah watershed in northern Georgia. Our goal is to move experimental designs in a direction that will further our mechanistic understanding of the effects of existing urbanization on aquatic ecosystems and will provide opportunities to evaluate stream responses to environmentally sensitive urban land cover.},
	number = {4},
	journal = {Journal of the North American Benthological Society},
	author = {Carter, Timothy and Jackson, C. Rhett and Rosemond, Amy and Pringle, Cathy and Radcliffe, David and Tollner, William and Maerz, John and Leigh, David and Trice, Amy},
	year = {2009},
	keywords = {and this proportion is, cities, development, environmental gradient, experimental design, impacts, now lives in, of the global population, over 50, paired watershed, projected to increase to, urban stream, urbanization},
	pages = {1038--1050},
}

Many studies have shown that streams degrade in response to urbanization in the watershed. These studies often are based on use of biotic and abiotic variables to measure stream health across a gradient of land cover/land use. The results of these studies can be applied to other urban systems, but often fail to provide a mechanistic understanding of the urban impact, in part, because of the nature of the experimental design. We analyzed the advantages and disadvantages of using environmental gradient studies to further understanding of urban stream systems. We also evaluated alternative experimental design approaches, including best management practice monitoring, long-term watershed studies, paired- watershed studies, and before–after control–impact studies, which could be used to complement the gradient approach. We illustrate these theoretical discussions with an urban paired-watershed case study in the Etowah watershed in northern Georgia. Our goal is to move experimental designs in a direction that will further our mechanistic understanding of the effects of existing urbanization on aquatic ecosystems and will provide opportunities to evaluate stream responses to environmentally sensitive urban land cover.

@article{davis_effects_2009,
	title = {Effects of chytridiomycosis on circulating white blood cell distributions of bullfrog larvae ({Rana} catesbeiana)},
	volume = {19},
	copyright = {All rights reserved},
	issn = {1618-5641 1618-565X},
	doi = {10.1007/s00580-009-0914-8},
	abstract = {Bullfrogs (Rana catesbeiana) are widely believed to be nonclinical carriers of Batrachochytrium dendrobatidis (Bd), the fungal pathogen that invades keratinized tissues of amphibians and causes the disease, chytridiomycosis. Although most research on this disease focuses on adults, larval anurans are also susceptible to infections in their keratinized mouthparts, and this allows for visual diagnosis of the disease via the degree of mouthpart depigmentation. When an unplanned outbreak of chytridiomycosis occurred in a set of captive bullfrog tadpoles in our lab, we conducted the current investigation into its effects on the nonspecific immune system (i.e., the leukocyte populations) of the tadpoles. We compared leukocyte counts from blood smears of 27 tadpoles that had contracted the disease (evidenced by severe mouthpart depigmentation and confirmed by histology) to those of 21 tadpoles that had little depigmentation (i.e., with little evidence of the disease). Tadpoles with severe depigmentation had significantly more neutrophils and less eosinophils than those with little depigmentation, while numbers of lymphocytes, basophils, and monocytes were not statistically different. That there was any effect at all on circulating leukocyte numbers is surprising since leukocytes are usually not seen migrating to sites of infection in tissue sections of amphibians infected with Bd, and since most research points to this disease having little outward effect on bullfrogs. Since monocyte numbers were unchanged, the leukocyte alterations were likely not due to a simple inflammation response. It is possible that Bd infections elicit increases in glucocorticoid hormones, which can cause increased numbers of circulating neutrophils and lower numbers of eosinophils, although this is often accompanied by a reduction in lymphocyte numbers, which we did not see. Further research is warranted to clarify if this effect is limited to this species.},
	number = {1},
	journal = {Comparative Clinical Pathology},
	author = {Davis, Andrew K and Keel, M Kevin and Ferreira, Andrew and Maerz, John C},
	year = {2009},
	pages = {49--55},
}

Bullfrogs (Rana catesbeiana) are widely believed to be nonclinical carriers of Batrachochytrium dendrobatidis (Bd), the fungal pathogen that invades keratinized tissues of amphibians and causes the disease, chytridiomycosis. Although most research on this disease focuses on adults, larval anurans are also susceptible to infections in their keratinized mouthparts, and this allows for visual diagnosis of the disease via the degree of mouthpart depigmentation. When an unplanned outbreak of chytridiomycosis occurred in a set of captive bullfrog tadpoles in our lab, we conducted the current investigation into its effects on the nonspecific immune system (i.e., the leukocyte populations) of the tadpoles. We compared leukocyte counts from blood smears of 27 tadpoles that had contracted the disease (evidenced by severe mouthpart depigmentation and confirmed by histology) to those of 21 tadpoles that had little depigmentation (i.e., with little evidence of the disease). Tadpoles with severe depigmentation had significantly more neutrophils and less eosinophils than those with little depigmentation, while numbers of lymphocytes, basophils, and monocytes were not statistically different. That there was any effect at all on circulating leukocyte numbers is surprising since leukocytes are usually not seen migrating to sites of infection in tissue sections of amphibians infected with Bd, and since most research points to this disease having little outward effect on bullfrogs. Since monocyte numbers were unchanged, the leukocyte alterations were likely not due to a simple inflammation response. It is possible that Bd infections elicit increases in glucocorticoid hormones, which can cause increased numbers of circulating neutrophils and lower numbers of eosinophils, although this is often accompanied by a reduction in lymphocyte numbers, which we did not see. Further research is warranted to clarify if this effect is limited to this species.

@article{nuzzo_earthworm_2009,
	title = {Earthworm invasion as the driving force behind plant invasion and community change in northeastern north american forests},
	volume = {23},
	copyright = {All rights reserved},
	doi = {10.1111/j.1523-1739.2009.01168.x},
	abstract = {Identification of factors that drive changes in plant community structure and contribute to decline and endangerment of native plant species is essential to the development of appropriate management strategies. Introduced species are assumed to be driving causes of shifts in native plant communities, but unequivocal evidence supporting this view is frequently lacking. We measured native vegetation, non-native earthworm biomass, and leaf-litter volume in 15 forests in the presence and absence of 3 non-native plant species (Microstegium vimineum, Alliaria petiolata, Berberis thunbergii) to assess the general impact of non-native plant and earthworm invasions on native plant communities in northeastern United States. Non-native plant cover was positively correlated with total native plant cover and non-native earthworm biomass. Earthworm biomass was negatively associated with cover of native woody and most herbaceous plants and with litter volume. Graminoid cover was positively associated with non-native earthworm biomass and non-native plant cover. These earthworm-associated responses were detected at all sites despite differences in earthworm species and abundance, composition of the native plant community, identity of invasive plant species, and geographic region. These patterns suggest earthworm invasion, rather than non-native plant invasion, is the driving force behind changes in forest plant communities in northeastern North America, including declines in native plant species, and earthworm invasions appear to facilitate plant invasions in these forests. Thus, a focus on management of invasive plant species may be insufficient to protect northeastern forest understory species. ? 2009 Society for Conservation Biology.},
	number = {4},
	journal = {Conservation Biology},
	author = {Nuzzo, V.A. and Maerz, J.C. and Blossey, B.},
	year = {2009},
	keywords = {Berberis thunbergii, Facilita, [Alliaria petiolata},
	pages = {996--974},
}

Identification of factors that drive changes in plant community structure and contribute to decline and endangerment of native plant species is essential to the development of appropriate management strategies. Introduced species are assumed to be driving causes of shifts in native plant communities, but unequivocal evidence supporting this view is frequently lacking. We measured native vegetation, non-native earthworm biomass, and leaf-litter volume in 15 forests in the presence and absence of 3 non-native plant species (Microstegium vimineum, Alliaria petiolata, Berberis thunbergii) to assess the general impact of non-native plant and earthworm invasions on native plant communities in northeastern United States. Non-native plant cover was positively correlated with total native plant cover and non-native earthworm biomass. Earthworm biomass was negatively associated with cover of native woody and most herbaceous plants and with litter volume. Graminoid cover was positively associated with non-native earthworm biomass and non-native plant cover. These earthworm-associated responses were detected at all sites despite differences in earthworm species and abundance, composition of the native plant community, identity of invasive plant species, and geographic region. These patterns suggest earthworm invasion, rather than non-native plant invasion, is the driving force behind changes in forest plant communities in northeastern North America, including declines in native plant species, and earthworm invasions appear to facilitate plant invasions in these forests. Thus, a focus on management of invasive plant species may be insufficient to protect northeastern forest understory species. ? 2009 Society for Conservation Biology.

@article{maerz_declines_2009,
	title = {Declines in woodland salamander abundance associated with non-native earthworm and plant invasions},
	volume = {23},
	copyright = {All rights reserved},
	doi = {10.1111/j.1523-1739.2009.01167.x},
	abstract = {Factors that negatively affect the quality of wildlife habitat are a major concern for conservation. Non-native species invasions, in particular, are perceived as a global threat to the quality of wildlife habitat. Recent evidence indicates that some changes to understory plant communities in northern temperate forests of North America, including invasions by 3 non-native plant species, are facilitated by non-native earthworm invasion. Furthermore, non-native earthworm invasions cause a reduction in leaf litter on the forest floor, and the loss of forest leaf litter is commonly associated with declines in forest fauna, including amphibians. We conducted a mark-recapture study of woodland salamander abundance across plant invasion fronts at 10 sites to determine whether earthworm or plant invasions were associated with reduced salamander abundance. Salamander abundance declined exponentially with decreasing leaf litter volume. There was no significant relationship between invasive plant cover and salamander abundance, independent of the effects of leaf litter loss due to earthworm invasion. An analysis of selected salamander prey abundance (excluding earthworms) at 4 sites showed that prey abundance declined with declining leaf litter. The loss of leaf litter layers due to non-native earthworm invasions appears to be negatively affecting woodland salamander abundance, in part, because of declines in the abundance of small arthropods that are a stable resource for salamanders. Our results demonstrate that earthworm invasions pose a significant threat to woodland amphibian fauna in the northeastern United States, and that plant invasions are symptomatic of degraded amphibian habitat but are not necessarily drivers of habitat degradation. ? 2009 Society for Conservation Biology.},
	number = {4},
	journal = {Conservation Biology},
	author = {Maerz, J.C. and Nuzzo, V.A. and Blossey, B.},
	year = {2009},
	keywords = {Berberis thunbergii, Hojarasc, [Alliaria petiolata},
	pages = {975--981},
}

Factors that negatively affect the quality of wildlife habitat are a major concern for conservation. Non-native species invasions, in particular, are perceived as a global threat to the quality of wildlife habitat. Recent evidence indicates that some changes to understory plant communities in northern temperate forests of North America, including invasions by 3 non-native plant species, are facilitated by non-native earthworm invasion. Furthermore, non-native earthworm invasions cause a reduction in leaf litter on the forest floor, and the loss of forest leaf litter is commonly associated with declines in forest fauna, including amphibians. We conducted a mark-recapture study of woodland salamander abundance across plant invasion fronts at 10 sites to determine whether earthworm or plant invasions were associated with reduced salamander abundance. Salamander abundance declined exponentially with decreasing leaf litter volume. There was no significant relationship between invasive plant cover and salamander abundance, independent of the effects of leaf litter loss due to earthworm invasion. An analysis of selected salamander prey abundance (excluding earthworms) at 4 sites showed that prey abundance declined with declining leaf litter. The loss of leaf litter layers due to non-native earthworm invasions appears to be negatively affecting woodland salamander abundance, in part, because of declines in the abundance of small arthropods that are a stable resource for salamanders. Our results demonstrate that earthworm invasions pose a significant threat to woodland amphibian fauna in the northeastern United States, and that plant invasions are symptomatic of degraded amphibian habitat but are not necessarily drivers of habitat degradation. ? 2009 Society for Conservation Biology.

@article{barry_amphibian_2008,
	title = {Amphibian use of man-made pools on clear-cuts in the {Allegheny} {Mountains} of {West} {Virginia}, {USA}},
	volume = {5},
	copyright = {All rights reserved},
	doi = {10.1163/157075408784648772},
	abstract = {Timber harvesting can alter habitats of forest-dwelling species and these alterations can be highly detrimental to species such as amphibians that are intimately associated with habitat temperature and moisture regimes. Consequently, information on conservation practices that can reduce impacts on these species can be useful to prevent local extinctions. Twenty-two of 40 pools constructed by the Fernow Experimental Station, USDA Northern Research Station, Parsons, West Virginia in 1993 on primitive haul roads in two clearcut areas on McGowan Mountain, Tucker County, WV were monitored for 3 years to determine their potential use by anurans. Monthly samples (April through September) of water chemistry and amphibian captures were taken to evaluate amphibian use of these pools. Anurans that used the pools to breed were Bufo americanus americanus, Rana sylvatica, Psuedacris brachyphona, and Hyla chrysoscelis. Desmognathus ochrophaeus and Gyrinophilus porphyriticus porphyriticus were also found in ponds but no evidence of breeding was discovered. By 1994, 14 of the 22 pools that held water were used by anurans for reproduction. Species richness of anurans that bred in pools was primarily dependent on pond depth. Man-made small but deep ponds placed carefully such that their hydroperiods are long enough for larvae to complete development (i.e., near seepages) provides breeding habitat for some frogs species, as well as refugia for non-breeding frogs and salamanders in clear-cut areas. Pools constructed at strategic locations on primitive roads have the potential to reduce adverse impacts of timber harvesting on some amphibian populations. ? 2008 Brill.},
	number = {2},
	journal = {Applied Herpetology},
	author = {Barry, D.S. and Pauley, T.K. and Maerz, J.C.},
	year = {2008},
	keywords = {Clear-cut, Man-made pools, West-Virgi, [Amphibians},
	pages = {121--128},
}

Timber harvesting can alter habitats of forest-dwelling species and these alterations can be highly detrimental to species such as amphibians that are intimately associated with habitat temperature and moisture regimes. Consequently, information on conservation practices that can reduce impacts on these species can be useful to prevent local extinctions. Twenty-two of 40 pools constructed by the Fernow Experimental Station, USDA Northern Research Station, Parsons, West Virginia in 1993 on primitive haul roads in two clearcut areas on McGowan Mountain, Tucker County, WV were monitored for 3 years to determine their potential use by anurans. Monthly samples (April through September) of water chemistry and amphibian captures were taken to evaluate amphibian use of these pools. Anurans that used the pools to breed were Bufo americanus americanus, Rana sylvatica, Psuedacris brachyphona, and Hyla chrysoscelis. Desmognathus ochrophaeus and Gyrinophilus porphyriticus porphyriticus were also found in ponds but no evidence of breeding was discovered. By 1994, 14 of the 22 pools that held water were used by anurans for reproduction. Species richness of anurans that bred in pools was primarily dependent on pond depth. Man-made small but deep ponds placed carefully such that their hydroperiods are long enough for larvae to complete development (i.e., near seepages) provides breeding habitat for some frogs species, as well as refugia for non-breeding frogs and salamanders in clear-cut areas. Pools constructed at strategic locations on primitive roads have the potential to reduce adverse impacts of timber harvesting on some amphibian populations. ? 2008 Brill.

@article{davis_comparison_2008,
	title = {Comparison of hematological stress indicators in recently captured and captive paedomorphic {Mole} {Salamanders}, {Ambystoma} talpoideum},
	volume = {2008},
	copyright = {All rights reserved},
	doi = {10.1643/CP-07-133},
	abstract = {Measuring stress in animals is an important component of many research studies, and it has traditionally been performed via sampling levels of corticosterone in plasma. A secondary, "hematological" approach used most commonly by researchers of birds, mammals, and other taxa involves evaluating leukocyte profiles from blood smears. Such research has shown that leukocytes have a characteristic response to stress, although in amphibians this phenomenon is not as well studied. In general, stress can induce a rise in the ratio of neutrophils to lymphocytes. We evaluated the hematological response of paedomorphic Mole Salamanders (Ambystoma talpoideum) to captivity stress, specifically focusing on this parameter, but also examining other white blood cell types. Individuals captured in the wild and held in captivity for ten days before sampling had significantly more neutrophils, fewer lymphocytes, and higher ratios of neutrophils to lymphocytes than those captured from the same locations and sampled within one hour. Captive individuals also had significantly higher numbers of eosinophils. These results are consistent with hematological research in birds and other taxa and highlight the utility of this approach for measuring stress in amphibians. ? 2008 by the American Society of Ichthyologists and Herpetologists.},
	number = {3},
	journal = {Copeia},
	author = {Davis, A.K. and Maerz, J.C.},
	year = {2008},
	pages = {613--617},
}

Measuring stress in animals is an important component of many research studies, and it has traditionally been performed via sampling levels of corticosterone in plasma. A secondary, "hematological" approach used most commonly by researchers of birds, mammals, and other taxa involves evaluating leukocyte profiles from blood smears. Such research has shown that leukocytes have a characteristic response to stress, although in amphibians this phenomenon is not as well studied. In general, stress can induce a rise in the ratio of neutrophils to lymphocytes. We evaluated the hematological response of paedomorphic Mole Salamanders (Ambystoma talpoideum) to captivity stress, specifically focusing on this parameter, but also examining other white blood cell types. Individuals captured in the wild and held in captivity for ten days before sampling had significantly more neutrophils, fewer lymphocytes, and higher ratios of neutrophils to lymphocytes than those captured from the same locations and sampled within one hour. Captive individuals also had significantly higher numbers of eosinophils. These results are consistent with hematological research in birds and other taxa and highlight the utility of this approach for measuring stress in amphibians. ? 2008 by the American Society of Ichthyologists and Herpetologists.

@article{davis_sex-related_2008,
	title = {Sex-related differences in hematological stress indices of breeding paedomorphic mole salamanders},
	volume = {42},
	copyright = {All rights reserved},
	doi = {10.1670/06-277R2.1},
	abstract = {Reproduction in amphibians is stressful and perhaps more so in females than males because of the higher energetic costs of producing eggs than sperm. The ratio of two white blood cells, neutrophils and lymphocytes, has been shown in birds, turtles, and amphibians to increase with stress. We captured breeding and nonbreeding, paedomorphic Mole Salamanders (Ambystoma talpoideum), to determine whether the stress of reproduction is reflected by neutrophil:lymphocyte ratios in this species. In blood smears of all individuals, we observed approximately 25.5 leukocytes per 1000 erythrocytes, with 13\% of the leukocytes being neutrophils, 41\% lymphocytes, and 46\% eosinophils. Less than 1\% of leukocytes were basophils and monocytes. Neutrophil:lymphocyte ratios of gravid females were significantly higher (and also more variable) than those of reproductive males and of nonreproductive individuals, indicating a higher degree of physiological stress in reproductive females. Reproductive males did not have higher ratios than nonreproductive individuals. We found no effect of body size on neutrophil:lymphocyte ratios. Our hematological stress results are consistent with studies of other amphibians where different methods were used and with other taxa. Copyright 2008 Society for the Study of Amphibians and Reptiles.},
	number = {1},
	journal = {Journal of Herpetology},
	author = {Davis, A.K. and Maerz, J.C.},
	year = {2008},
	pages = {197--201},
}

Reproduction in amphibians is stressful and perhaps more so in females than males because of the higher energetic costs of producing eggs than sperm. The ratio of two white blood cells, neutrophils and lymphocytes, has been shown in birds, turtles, and amphibians to increase with stress. We captured breeding and nonbreeding, paedomorphic Mole Salamanders (Ambystoma talpoideum), to determine whether the stress of reproduction is reflected by neutrophil:lymphocyte ratios in this species. In blood smears of all individuals, we observed approximately 25.5 leukocytes per 1000 erythrocytes, with 13% of the leukocytes being neutrophils, 41% lymphocytes, and 46% eosinophils. Less than 1% of leukocytes were basophils and monocytes. Neutrophil:lymphocyte ratios of gravid females were significantly higher (and also more variable) than those of reproductive males and of nonreproductive individuals, indicating a higher degree of physiological stress in reproductive females. Reproductive males did not have higher ratios than nonreproductive individuals. We found no effect of body size on neutrophil:lymphocyte ratios. Our hematological stress results are consistent with studies of other amphibians where different methods were used and with other taxa. Copyright 2008 Society for the Study of Amphibians and Reptiles.

@article{davis_use_2008,
	title = {The use of leukocyte profiles to measure stress in vertebrates: {A} review for ecologists},
	volume = {22},
	copyright = {All rights reserved},
	doi = {10.1111/j.1365-2435.2008.01467.x},
	abstract = {1. A growing number of ecologists are turning to the enumeration of white blood cells from blood smears (leukocyte profiles) to assess stress in animals. There has been some inconsistency and controversy in the ecological literature, however, regarding their interpretation. The inconsistencies may stem partly from a lack of information regarding how stress affects leukocytes in different taxa, and partly from a failure on the part of researchers in one discipline to consult potentially informative literature from another. 2. Here, we seek to address both issues by reviewing the literature on the leukocyte response to stress, spanning the taxa of mammals (including humans), birds, amphibians, reptiles and fish. 3. We show that much of the early literature points to a close link between leukocyte profiles and glucocorticoid levels. Specifically, these hormones act to increase the number and percentage of neutrophils (heterophils in birds and reptiles), while decreasing the number and percentage of lymphocytes. This phenomenon is seen in all five vertebrate taxa in response to either natural stressors or exogenous administration of stress hormones. For the ecologist, therefore, high ratios of heterophils or neutrophils to lymphocytes ('H : L' or 'N : L' ratios) in blood samples reliably indicate high glucocorticoid levels. Furthermore, this close relationship between stress hormones and N : L or H : L ratios needs to be highlighted more prominently in haematological assessments of stress, as it aids the interpretation of results. 4. As with hormone assays, there are challenges to overcome in the use of leukocytes profiles to assess levels of stress; however, there are also advantages to this approach, and we outline each. Given the universal and consistent nature of the haematological response to stress, plus the overwhelming evidence from the veterinary, biomedical and ecological literature reviewed here, we conclude that this method can provide a reliable assessment of stress in all vertebrate taxa. ? 2008 The Authors.},
	number = {5},
	journal = {Functional Ecology},
	author = {Davis, A.K. and Maney, D.L. and Maerz, J.C.},
	year = {2008},
	keywords = {Heterophils, Leukocytes, Lymphoc, [Glucocorticoids},
	pages = {760--772},
}

1. A growing number of ecologists are turning to the enumeration of white blood cells from blood smears (leukocyte profiles) to assess stress in animals. There has been some inconsistency and controversy in the ecological literature, however, regarding their interpretation. The inconsistencies may stem partly from a lack of information regarding how stress affects leukocytes in different taxa, and partly from a failure on the part of researchers in one discipline to consult potentially informative literature from another. 2. Here, we seek to address both issues by reviewing the literature on the leukocyte response to stress, spanning the taxa of mammals (including humans), birds, amphibians, reptiles and fish. 3. We show that much of the early literature points to a close link between leukocyte profiles and glucocorticoid levels. Specifically, these hormones act to increase the number and percentage of neutrophils (heterophils in birds and reptiles), while decreasing the number and percentage of lymphocytes. This phenomenon is seen in all five vertebrate taxa in response to either natural stressors or exogenous administration of stress hormones. For the ecologist, therefore, high ratios of heterophils or neutrophils to lymphocytes ('H : L' or 'N : L' ratios) in blood samples reliably indicate high glucocorticoid levels. Furthermore, this close relationship between stress hormones and N : L or H : L ratios needs to be highlighted more prominently in haematological assessments of stress, as it aids the interpretation of results. 4. As with hormone assays, there are challenges to overcome in the use of leukocytes profiles to assess levels of stress; however, there are also advantages to this approach, and we outline each. Given the universal and consistent nature of the haematological response to stress, plus the overwhelming evidence from the veterinary, biomedical and ecological literature reviewed here, we conclude that this method can provide a reliable assessment of stress in all vertebrate taxa. ? 2008 The Authors.

@article{davis_fast_2008,
	title = {A fast, non-invasive method of measuring growth in tadpoles using image analysis},
	volume = {39},
	copyright = {All rights reserved},
	number = {1},
	journal = {Herpetological Review},
	author = {Davis, A.K. and Connell, L.L. and Grosse, A. and Maerz, J.C.},
	year = {2008},
	pages = {56--58},
}

@article{davis_discovery_2007,
	title = {Discovery of a novel alveolate pathogen affecting {Southern} {Leopard} {Frogs} in {Georgia}: description of the disease and host effects},
	volume = {4},
	copyright = {All rights reserved},
	issn = {1612-9202 1612-9210},
	doi = {10.1007/s10393-007-0115-3},
	abstract = {In April of 2006, we observed southern leopard frog (Rana sphenocephala) tadpoles in a pond in northeast Georgia that were dying from an unknown pathogen. Examination of affected specimens, as well as PCR characterization, revealed that all were infected with a novel alveolate pathogen closely related to freshwater and marine eukaryotic organisms and, to a lesser degree, to members of the genus Perkinsus. This pathogen has been documented in numerous mortality events in anuran tadpoles in the United States, although it has not yet been named nor clearly described. We subsequently conducted a systematic survey of this and four other ponds in the same area to document the extent of the pathogen and to describe the nature of infections in leopard frog tadpoles. Of 87 live tadpoles examined, 25\% were infected with the alveolate pathogen, based on visual inspection of tadpole liver tissue. Affected tadpoles frequently had enlarged abdomens, swam erratically, and could be captured by hand. All organs of infected tadpoles were infiltrated but typically to a lesser extent than the liver and kidneys, which often had hundreds of thousands of the spherical, 6-lm organisms. Infected tadpoles tended to weigh more than noninfected ones, likely due to the massive organ swelling that coincided with infections. Infected tadpoles did not differ in developmental stage from noninfected tadpoles. Infection prevalence varied widely among ponds, and in one pond, we witnessed a rapid die-off of R. spenocephala tadpoles during our surveys, although we did find infected metamorphic frogs. The rapid mortality we observed as well as the vast number of organisms seen in specimens suggests that this pathogen has tremendous transmission potential, and therefore deserves further monitoring and study.},
	number = {3},
	journal = {Ecohealth},
	author = {Davis, Andrew K and Yabsley, Michael J and Kevin Keel, M and Maerz, John C},
	year = {2007},
	pages = {310--317},
}

In April of 2006, we observed southern leopard frog (Rana sphenocephala) tadpoles in a pond in northeast Georgia that were dying from an unknown pathogen. Examination of affected specimens, as well as PCR characterization, revealed that all were infected with a novel alveolate pathogen closely related to freshwater and marine eukaryotic organisms and, to a lesser degree, to members of the genus Perkinsus. This pathogen has been documented in numerous mortality events in anuran tadpoles in the United States, although it has not yet been named nor clearly described. We subsequently conducted a systematic survey of this and four other ponds in the same area to document the extent of the pathogen and to describe the nature of infections in leopard frog tadpoles. Of 87 live tadpoles examined, 25% were infected with the alveolate pathogen, based on visual inspection of tadpole liver tissue. Affected tadpoles frequently had enlarged abdomens, swam erratically, and could be captured by hand. All organs of infected tadpoles were infiltrated but typically to a lesser extent than the liver and kidneys, which often had hundreds of thousands of the spherical, 6-lm organisms. Infected tadpoles tended to weigh more than noninfected ones, likely due to the massive organ swelling that coincided with infections. Infected tadpoles did not differ in developmental stage from noninfected tadpoles. Infection prevalence varied widely among ponds, and in one pond, we witnessed a rapid die-off of R. spenocephala tadpoles during our surveys, although we did find infected metamorphic frogs. The rapid mortality we observed as well as the vast number of organisms seen in specimens suggests that this pathogen has tremendous transmission potential, and therefore deserves further monitoring and study.

@article{davis_spot_2007,
	title = {Spot symmetry predicts body condition in spotted salamanders, {Ambystoma} maculatuam},
	volume = {4},
	copyright = {All rights reserved},
	abstract = {Reports of global amphibian declines necessitate a focus on measures of population health. Fluctuating asymmetry (FA) is a potential measure of the developmental stress experienced by individuals in different environments, but few studies have linked FA with measures of individual quality in amphibians, which is an important assumption of FA. The spotted salamander, Ambystoma maculatum, has two rows of yellow spots on its dorsal surface which might represent useful characters in FA analyses and population monitoring, provided they truly reflect the quality of individuals. In this paper we compared left-right asymmetry in spot features (spot number, size and shape) and leg lengths of this species with traditional measures of body size and body condition among museum specimens to address this question. Of all three spot symmetry variables, the simplest (the difference in left- right spot numbers) was the most important. Individuals with asymmetrical spot numbers were also more asymmetrical in hind leg length, evidence that spots are supposed to be symmetrical in this species. Moreover, salamanders with symmetrical numbers of left-right dorsal spots had higher body condition scores than those with asymmetrical spot numbers. Combined, our results indicate that spot number symmetry provides a good index of individual quality. Further, as many proximate factors can influence body condition (such as recent foraging history), FA in characters such as spots or limbs may provide a more stable metric for assessing the developmental health or quality of individuals, which would prove valuable in amphibian conservation programs.},
	journal = {Applied Herpetology},
	author = {Davis, A K and Maerz, John C},
	year = {2007},
	pages = {195--205},
}

Reports of global amphibian declines necessitate a focus on measures of population health. Fluctuating asymmetry (FA) is a potential measure of the developmental stress experienced by individuals in different environments, but few studies have linked FA with measures of individual quality in amphibians, which is an important assumption of FA. The spotted salamander, Ambystoma maculatum, has two rows of yellow spots on its dorsal surface which might represent useful characters in FA analyses and population monitoring, provided they truly reflect the quality of individuals. In this paper we compared left-right asymmetry in spot features (spot number, size and shape) and leg lengths of this species with traditional measures of body size and body condition among museum specimens to address this question. Of all three spot symmetry variables, the simplest (the difference in left- right spot numbers) was the most important. Individuals with asymmetrical spot numbers were also more asymmetrical in hind leg length, evidence that spots are supposed to be symmetrical in this species. Moreover, salamanders with symmetrical numbers of left-right dorsal spots had higher body condition scores than those with asymmetrical spot numbers. Combined, our results indicate that spot number symmetry provides a good index of individual quality. Further, as many proximate factors can influence body condition (such as recent foraging history), FA in characters such as spots or limbs may provide a more stable metric for assessing the developmental health or quality of individuals, which would prove valuable in amphibian conservation programs.

@article{brown_invasive_2006,
	title = {Invasive plant and experimental venue affect tadpole performance},
	volume = {8},
	copyright = {All rights reserved},
	doi = {10.1007/s10530-004-8244-x},
	abstract = {Introductions of non-native predators and competitors appear to contribute to worldwide amphibian declines; however, potential negative impacts of invasive plants on habitat quality and amphibian populations have not been examined. Loss of diversity and alterations in ecosystem function associated with plant invasions may disrupt food webs, potentially leading to further declines of already threatened amphibian populations. We used a combination of small bins, mesocosms, and field experiments to examine the impacts of Eurasian purple loosestrife (Lythrum salicaria) replacing native cattails (Typha latifolia) in North American freshwater wetlands on survival, developmental rate, and diet (freshwater algae) of American toad (Bufo americanus) tadpoles. Tadpoles developed slower in L. salicaria compared to tadpoles developing in T. latifolia. This effect was consistent across experimental venues, although mesocosms showed this effect only in the second year of our study. Survival and development rates were always more variable in purple loosestrife than in cattail. In bins, tadpoles showed significantly reduced survival when raised in purple loosestrife extract and addition of leaf litter exacerbated this negative effect. Tadpole survival rates in mesocosms and field cages were not significantly different between plant species, most likely an effect of high variability among replicates. We suspect a combination of direct toxicity of high tannin concentrations in L. salicaria leaves and their indirect negative impacts on aquatic food webs are responsible for these results. Tadpole gut analyses revealed differences in algal communities among venues and between L. salicaria and T. latifolia suggesting that alterations in tadpole food quality and quantity contribute to the observed reduced tadpole performance. The replacement of native wetland plant species by L. salicaria does not represent a simple exchange of ecological equivalents and the function of invaded habitats for native species has clearly changed. While we were investigating only a single amphibian species, our results suggest that the impact of L. salicaria on ecosystem processes and aquatic food webs may be more general and likely to negatively affect other wetland species. The threats non-indigenous plants represent for amphibian populations and food webs may be underestimated, and warrant further investigation. ? Springer 2006.},
	number = {2},
	journal = {Biological Invasions},
	author = {Brown, C.J. and Blossey, B. and Maerz, J.C. and Joule, S.J.},
	year = {2006},
	keywords = {Food web effects, Freshwater, [Amphibian declines},
	pages = {327--338},
}

Introductions of non-native predators and competitors appear to contribute to worldwide amphibian declines; however, potential negative impacts of invasive plants on habitat quality and amphibian populations have not been examined. Loss of diversity and alterations in ecosystem function associated with plant invasions may disrupt food webs, potentially leading to further declines of already threatened amphibian populations. We used a combination of small bins, mesocosms, and field experiments to examine the impacts of Eurasian purple loosestrife (Lythrum salicaria) replacing native cattails (Typha latifolia) in North American freshwater wetlands on survival, developmental rate, and diet (freshwater algae) of American toad (Bufo americanus) tadpoles. Tadpoles developed slower in L. salicaria compared to tadpoles developing in T. latifolia. This effect was consistent across experimental venues, although mesocosms showed this effect only in the second year of our study. Survival and development rates were always more variable in purple loosestrife than in cattail. In bins, tadpoles showed significantly reduced survival when raised in purple loosestrife extract and addition of leaf litter exacerbated this negative effect. Tadpole survival rates in mesocosms and field cages were not significantly different between plant species, most likely an effect of high variability among replicates. We suspect a combination of direct toxicity of high tannin concentrations in L. salicaria leaves and their indirect negative impacts on aquatic food webs are responsible for these results. Tadpole gut analyses revealed differences in algal communities among venues and between L. salicaria and T. latifolia suggesting that alterations in tadpole food quality and quantity contribute to the observed reduced tadpole performance. The replacement of native wetland plant species by L. salicaria does not represent a simple exchange of ecological equivalents and the function of invaded habitats for native species has clearly changed. While we were investigating only a single amphibian species, our results suggest that the impact of L. salicaria on ecosystem processes and aquatic food webs may be more general and likely to negatively affect other wetland species. The threats non-indigenous plants represent for amphibian populations and food webs may be underestimated, and warrant further investigation. ? Springer 2006.

@article{maerz_trophic_2006,
	title = {Trophic polymorphism in a terrestrial salamander},
	volume = {8},
	copyright = {All rights reserved},
	url = {file:///C:/Documents and Settings/jmaerz/My Documents/John C. Maerz III/Reprints/Maerz et al 2006 EER.pdf},
	abstract = {Question: Does habitat heterogeneity promote trophic polymorphism in a terrestrial salamander? 

Hypothesis: Eastern red-backed salamanders (Plethodon cinereus) in upland and lowland habitats differ morphologically because their prey’s size differs between those habitats. 

Field site: Five mature hardwood forests in central New York and northern Pennsylvania, USA, with known differences in diet between upland and lowland habitats. 

Methods: We collected animals and examined their stomach contents and their cranial morphology, the latter with digital stereomicroscope images and morphometric methods. 

Results: We found morphological differences between upland and lowland salamanders, although there was a considerable phenotypic range for both habitats. Lowland salamanders generally had relatively shorter heads and a lower jaw/head ratio, and upland salamanders generally had the converse. Within and among habitats, cranial morphology was associated with diet, where salamanders with lowland-like morphology consumed more large prey and fewer small prey, and salamanders with upland-like morphology consumed the converse. 

Conclusions: The observed trophic polymorphism and association with food use within populations suggests that this variation may accentuate variation at larger scales, and may play an important role in diversification within the genus.},
	journal = {Evolutionary Ecology Research},
	author = {Maerz, John C and Myers, Erin M and Adams, Dean C},
	year = {2006},
	keywords = {Plethodon cinereus, Plethodontidae, amphibian, local adaptation, resource use, trophic polymorphism},
	pages = {23--35},
}

Question: Does habitat heterogeneity promote trophic polymorphism in a terrestrial salamander? Hypothesis: Eastern red-backed salamanders (Plethodon cinereus) in upland and lowland habitats differ morphologically because their prey’s size differs between those habitats. Field site: Five mature hardwood forests in central New York and northern Pennsylvania, USA, with known differences in diet between upland and lowland habitats. Methods: We collected animals and examined their stomach contents and their cranial morphology, the latter with digital stereomicroscope images and morphometric methods. Results: We found morphological differences between upland and lowland salamanders, although there was a considerable phenotypic range for both habitats. Lowland salamanders generally had relatively shorter heads and a lower jaw/head ratio, and upland salamanders generally had the converse. Within and among habitats, cranial morphology was associated with diet, where salamanders with lowland-like morphology consumed more large prey and fewer small prey, and salamanders with upland-like morphology consumed the converse. Conclusions: The observed trophic polymorphism and association with food use within populations suggests that this variation may accentuate variation at larger scales, and may play an important role in diversification within the genus.

@article{brown_clinical_2006,
	title = {Clinical challenge},
	volume = {37},
	copyright = {All rights reserved},
	number = {4},
	journal = {Journal of Zoo and Wildlife Medicine},
	author = {Brown, J.D. and Keel, M.K. and Yabsley, M.J. and Thigpen, T. and Maerz, J.C.},
	year = {2006},
	keywords = {Hannemania, Mites, Plethodon metcalfi, [Dermatitis},
}

@article{migge-kleian_influence_2006,
	title = {The influence of invasive earthworms on indigenous fauna in ecosystems previously uninhabited by earthworms},
	volume = {8},
	copyright = {All rights reserved},
	doi = {10.1007/s10530-006-9021-9},
	abstract = {Recent studies on earthworm invasion of North American soils report dramatic changes in soil structure, nutrient dynamics and plant communities in ecosystems historically free of earthworms. However, the direct and indirect impacts of earthworm invasions on animals have been largely ignored. This paper summarizes the current knowledge on the impact of earthworm invasion on other soil fauna, vertebrates as well as invertebrates. Earthworm invasions can have positive effects on the abundance of other soil invertebrates, but such effects are often small, transient, and restricted to habitats with harsh climates or a long history of earthworm co-occurrence with other soil invertebrates. Middens and burrows can increase soil heterogeneity and create microhabitats with a larger pore size, high microbial biomass, and microclimates that are attractive to micro- and mesofauna. Under harsh climatic conditions, the aggregates formed by earthworms may increase the stability of soil microclimates. Positive effects can also be seen when comminution and mucus secretion increase the palatability of unpalatable organic material for microorganisms which are the main food of most micro- and mesofaunal groups. For larger invertebrates or small vertebrates, invasive earthworms may become important prey, with the potential to increase resource availability. In the longer-term, the activity of invading earthworms can have a strong negative impact on indigenous faunal groups across multiple trophic levels. Evidence from field and laboratory studies indicates that the restructuring of soil layers, particularly the loss of organic horizons, physical disturbance to the soil, alteration of understory vegetation, and direct competition for food resources, lead directly and indirectly to significant declines in the abundance of soil micro- and mesofauna. Though studies of invasive earthworm impacts on the abundance of larger invertebrates or vertebrates are generally lacking, recent evidence suggests that reduced abundance of small soil fauna and alteration of soil microclimates may be contributing to declines in vertebrate fauna such as terrestrial salamanders. Preliminary evidence also suggests the potential for earthworm invasions to interact with other factors such as soil pollution, to negatively affect vertebrate populations. ? Springer Science+Business Media B.V. 2006.},
	number = {6},
	journal = {Biological Invasions},
	author = {Migge-Kleian, S. and McLean, M.A. and Maerz, J.C. and Heneghan, L.},
	year = {2006},
	keywords = {Collembola, Disturbance, Ear, [Biological invasion},
	pages = {1275--1285},
}

Recent studies on earthworm invasion of North American soils report dramatic changes in soil structure, nutrient dynamics and plant communities in ecosystems historically free of earthworms. However, the direct and indirect impacts of earthworm invasions on animals have been largely ignored. This paper summarizes the current knowledge on the impact of earthworm invasion on other soil fauna, vertebrates as well as invertebrates. Earthworm invasions can have positive effects on the abundance of other soil invertebrates, but such effects are often small, transient, and restricted to habitats with harsh climates or a long history of earthworm co-occurrence with other soil invertebrates. Middens and burrows can increase soil heterogeneity and create microhabitats with a larger pore size, high microbial biomass, and microclimates that are attractive to micro- and mesofauna. Under harsh climatic conditions, the aggregates formed by earthworms may increase the stability of soil microclimates. Positive effects can also be seen when comminution and mucus secretion increase the palatability of unpalatable organic material for microorganisms which are the main food of most micro- and mesofaunal groups. For larger invertebrates or small vertebrates, invasive earthworms may become important prey, with the potential to increase resource availability. In the longer-term, the activity of invading earthworms can have a strong negative impact on indigenous faunal groups across multiple trophic levels. Evidence from field and laboratory studies indicates that the restructuring of soil layers, particularly the loss of organic horizons, physical disturbance to the soil, alteration of understory vegetation, and direct competition for food resources, lead directly and indirectly to significant declines in the abundance of soil micro- and mesofauna. Though studies of invasive earthworm impacts on the abundance of larger invertebrates or vertebrates are generally lacking, recent evidence suggests that reduced abundance of small soil fauna and alteration of soil microclimates may be contributing to declines in vertebrate fauna such as terrestrial salamanders. Preliminary evidence also suggests the potential for earthworm invasions to interact with other factors such as soil pollution, to negatively affect vertebrate populations. ? Springer Science+Business Media B.V. 2006.

@article{maerz_green_2005,
	title = {Green frogs show reduced foraging success in habitats invaded by {Japanese} knotweed},
	volume = {14},
	copyright = {All rights reserved},
	doi = {10.1007/s10531-004-0223-0},
	abstract = {Habitat loss is causing amphibian population declines worldwide, so there is increased attention to forces that degrade remaining habitats. Terrestrial habitats surrounding wetlands are critical foraging areas for temperate anurans. We investigated plant community changes in two old fields invaded by Japanese knotweed (Fallopia japonica) and the foraging success of Green frogs (Rana clamitans) in invaded and non-invaded portions of those fields. Within each field, vegetation data were recorded in quadrats located along two transects bisecting the invasion fronts. We placed frogs in 'foraging buckets' along transects and measured their change in mass over a 38 h period. There were significant changes in vegetation structure and composition associated with Japanese knotweed invasion. Diverse assemblages of native plants that covered non-invaded plots were absent from areas invaded by Japanese knotweed. There was also a significant change in vegetation architecture between invaded and non-invaded habitats. Change in frog mass declined significantly along transects, with most frogs in non-invaded plots gaining mass and no frogs in invaded plots gaining mass. Most frogs from non-invaded plots but only two from invaded plots defecated shortly after removal from foraging buckets (verification of recent feeding). We hypothesize that Japanese knotweed invasions degrade terrestrial habitat quality for frogs by indirectly reducing arthropod abundance. Nonnative plant invasions may be another factor contributing to amphibian population declines. ? Springer 2005.},
	number = {12},
	journal = {Biodiversity and Conservation},
	author = {Maerz, J.C. and Blossey, B. and Nuzzo, V.},
	year = {2005},
	keywords = {Invasive plants, Landscape com, [Fallopia japonica},
	pages = {2901--2911},
}

Habitat loss is causing amphibian population declines worldwide, so there is increased attention to forces that degrade remaining habitats. Terrestrial habitats surrounding wetlands are critical foraging areas for temperate anurans. We investigated plant community changes in two old fields invaded by Japanese knotweed (Fallopia japonica) and the foraging success of Green frogs (Rana clamitans) in invaded and non-invaded portions of those fields. Within each field, vegetation data were recorded in quadrats located along two transects bisecting the invasion fronts. We placed frogs in 'foraging buckets' along transects and measured their change in mass over a 38 h period. There were significant changes in vegetation structure and composition associated with Japanese knotweed invasion. Diverse assemblages of native plants that covered non-invaded plots were absent from areas invaded by Japanese knotweed. There was also a significant change in vegetation architecture between invaded and non-invaded habitats. Change in frog mass declined significantly along transects, with most frogs in non-invaded plots gaining mass and no frogs in invaded plots gaining mass. Most frogs from non-invaded plots but only two from invaded plots defecated shortly after removal from foraging buckets (verification of recent feeding). We hypothesize that Japanese knotweed invasions degrade terrestrial habitat quality for frogs by indirectly reducing arthropod abundance. Nonnative plant invasions may be another factor contributing to amphibian population declines. ? Springer 2005.

@incollection{madison_decline_2005,
	address = {New York},
	title = {Decline in avoidance of predator chemical cues: habituation or biorhythm shif?},
	copyright = {All rights reserved},
	abstract = {Animals for behavioral studies are often brought into captivity out of necessity or to control for experimental variables, and are often used repetitively in experiments for similar reasons. A mix of potential difficulties can be generated ranging from potential captivity effects to pseudoreplication, making interpretation difficult. Problems arising from these studies are seldom identified or reported. We have conducted long-term studies of the avoidance response of red-backed salamanders (Plethodon cinereus) to chemical cues from predatory eastern garter snakes (Thamnophis sirtalis), and have found that freshly-captured salamanders always avoid chemical cues from T. sirtalis that have recently fed on P. cinereus.  In recent studies, salamanders held captive 5 months during summer and used randomly in multiple tests showed no decrease in predator avoidance behavior or activity, but a comparable group of salamanders maintained during winter showed a progressive loss of avoidance and activity. We discuss possible interpretations and suggest that the results reflect a natural decline in predator sensitivity or metabolism during winter rather than being a consequence of captivity or the outcome of habituation to predator chemical cues.},
	booktitle = {Advances in {Chemical} {Signals} in {Vertebrates} {X}},
	publisher = {Springer},
	author = {Madison, Dale M and Maerz, John C and Sullivan, Aaron M},
	editor = {Mason, R T and LeMaster, M P and Müller-Schwarze, D},
	year = {2005},
	keywords = {amphibian, behavioral biorhythms, chemical alarm cues, predation, research},
	pages = {365--372},
}

Animals for behavioral studies are often brought into captivity out of necessity or to control for experimental variables, and are often used repetitively in experiments for similar reasons. A mix of potential difficulties can be generated ranging from potential captivity effects to pseudoreplication, making interpretation difficult. Problems arising from these studies are seldom identified or reported. We have conducted long-term studies of the avoidance response of red-backed salamanders (Plethodon cinereus) to chemical cues from predatory eastern garter snakes (Thamnophis sirtalis), and have found that freshly-captured salamanders always avoid chemical cues from T. sirtalis that have recently fed on P. cinereus. In recent studies, salamanders held captive 5 months during summer and used randomly in multiple tests showed no decrease in predator avoidance behavior or activity, but a comparable group of salamanders maintained during winter showed a progressive loss of avoidance and activity. We discuss possible interpretations and suggest that the results reflect a natural decline in predator sensitivity or metabolism during winter rather than being a consequence of captivity or the outcome of habituation to predator chemical cues.

@article{maerz_can_2005,
	title = {Can secondary compounds of an invasive plant affect larval amphibians?},
	volume = {19},
	copyright = {All rights reserved},
	doi = {10.1111/j.1365-2435.2005.01054.x},
	abstract = {1. There is significant concern over the impacts of plant invasions on habitat quality for native fauna. Recent research suggests that non-native Purple Loosestrife (Lythrum salicaria) invasions may negatively affect the performance of larval American Toad tadpoles (Bufo americanus), and that compounds leached from L. salicaria leaves play a direct or indirect role in this effect. 2. We raised individual B. americanus and Gray Treefrog (Hyla versicolor) tadpoles on high-quality diets in aqueous extracts of senescent leaves from L. salicaria, native Broad-Leaf Cattail (Typha latifolia), and control water to determine whether loosestrife extracts directly affect anuran tadpole performance. 3. Even at high artificial food levels, B. americanus survival was significantly lower in L. salicaria extracts compared with T. latifolia extracts and a water control. Food level strongly affected B. americanus development, but tadpoles raised in L. salicaria extract were less developed compared with conspecifics raised in cattail extract or water. Unlike B. americanus, Hyla performance was not affected by exposure to any plant extract compared with the water control. 4. Our study implicates secondary plant compounds as a mechanism underlying the impact of an invasive plant on some but not all native fauna. We hypothesize that high tannin concentrations of L. salicaria leaves have the potential to create environments that are directly toxic to B. americanus tadpoles. We hypothesize that obligate gill breathers such as B. americanus tadpoles are highly sensitive to gill damage caused by high concentrations of phenolics. Other anuran species such as H. versicolor that develop well-functioning lungs early may be less affected by high tannin concentrations. ? 2005 British Ecological Society.},
	number = {6},
	journal = {Functional Ecology},
	author = {Maerz, J.C. and Brown, C.J. and Chapin, C.T. and Blossey, B.},
	year = {2005},
	keywords = {Bufo americanus, Detritus, Hyla, [Amphibian larvae},
	pages = {970--975},
}

1. There is significant concern over the impacts of plant invasions on habitat quality for native fauna. Recent research suggests that non-native Purple Loosestrife (Lythrum salicaria) invasions may negatively affect the performance of larval American Toad tadpoles (Bufo americanus), and that compounds leached from L. salicaria leaves play a direct or indirect role in this effect. 2. We raised individual B. americanus and Gray Treefrog (Hyla versicolor) tadpoles on high-quality diets in aqueous extracts of senescent leaves from L. salicaria, native Broad-Leaf Cattail (Typha latifolia), and control water to determine whether loosestrife extracts directly affect anuran tadpole performance. 3. Even at high artificial food levels, B. americanus survival was significantly lower in L. salicaria extracts compared with T. latifolia extracts and a water control. Food level strongly affected B. americanus development, but tadpoles raised in L. salicaria extract were less developed compared with conspecifics raised in cattail extract or water. Unlike B. americanus, Hyla performance was not affected by exposure to any plant extract compared with the water control. 4. Our study implicates secondary plant compounds as a mechanism underlying the impact of an invasive plant on some but not all native fauna. We hypothesize that high tannin concentrations of L. salicaria leaves have the potential to create environments that are directly toxic to B. americanus tadpoles. We hypothesize that obligate gill breathers such as B. americanus tadpoles are highly sensitive to gill damage caused by high concentrations of phenolics. Other anuran species such as H. versicolor that develop well-functioning lungs early may be less affected by high tannin concentrations. ? 2005 British Ecological Society.

@article{maerz_introduced_2005,
	title = {Introduced invertebrates are important prey for a generalist predator},
	volume = {11},
	copyright = {All rights reserved},
	doi = {10.1111/j.1366-9516.2005.00125.x},
	abstract = {Concern over biological invasions has drawn increased attention to the impacts of introduced predators or competitors, but not to the importance of introduced prey. North American forests are rich in introduced invertebrates, including species that represent relatively novel taxonomic or trophic guilds and show biased distributions among forest types. We analysed the diets of red-backed salamanders, Plethodon cinereus, from three upland and three lowland forests to determine whether introduced prey are important contributors to geographical or temporal variation in salamander food resources. We found several introduced species were volumetrically important salamander prey, and were responsible for resource differences between forest types and much of the seasonal fluctuation in food resources in both forest types. In lowland forests, rain had a stronger effect on salamander predation on non-native earthworms than native taxa, creating more dynamic resource fluctuations in resource levels than was observed in upland forests where earthworms were absent. With one exception, predation on non-native species was positively associated with predation on native species, suggesting non-native prey have added to salamander resources rather than replaced salamander predation on native taxa. We hypothesize that the novel resource gradients created by non-native prey introductions are contributing to patterns of geographical and temporal phenotypic variation among salamander populations.},
	number = {1},
	journal = {Diversity and Distributions},
	author = {Maerz, J.C. and Karuzas, J.M. and Madison, D.M. and Blossey, B.},
	year = {2005},
	keywords = {Biological invasions, Earthworms, Fore, [Amphibian},
	pages = {83--90},
}

Concern over biological invasions has drawn increased attention to the impacts of introduced predators or competitors, but not to the importance of introduced prey. North American forests are rich in introduced invertebrates, including species that represent relatively novel taxonomic or trophic guilds and show biased distributions among forest types. We analysed the diets of red-backed salamanders, Plethodon cinereus, from three upland and three lowland forests to determine whether introduced prey are important contributors to geographical or temporal variation in salamander food resources. We found several introduced species were volumetrically important salamander prey, and were responsible for resource differences between forest types and much of the seasonal fluctuation in food resources in both forest types. In lowland forests, rain had a stronger effect on salamander predation on non-native earthworms than native taxa, creating more dynamic resource fluctuations in resource levels than was observed in upland forests where earthworms were absent. With one exception, predation on non-native species was positively associated with predation on native species, suggesting non-native prey have added to salamander resources rather than replaced salamander predation on native taxa. We hypothesize that the novel resource gradients created by non-native prey introductions are contributing to patterns of geographical and temporal phenotypic variation among salamander populations.

@incollection{sullivan_nocturnal_2005,
	address = {New York},
	title = {Nocturnal shift in the antipredator response to predator-diet cues in laboratory and field trials},
	copyright = {All rights reserved},
	abstract = {The effects of predator diet on prey anti-predator responses to chemical cues may be crucial to understanding predator-prey interactions. In this study we examined how predator diet influenced red-backed salamander (Plethodon cinereus) responses to chemical traces from garter snakes (Thamnophis sirtalis) fed red-backed salamanders and northern two-lined salamanders (Eurycea bislineata) at two different periods of their active cycle. During early evening (around sunset), P. cinereus avoided all predator chemical traces regardless of snake diet, with neither treatment being avoided more than the other in treatment comparisons. Late at night, only the chemical traces from snakes fed P. cinereus elicited avoidance, even when treatments were tested against one another. The relative avoidance of treatments late at night suggests that the chemical cues eliciting avoidance is not generalized among plethodontid salamanders, and that chemical traces of related organisms in the predator's diet may contribute to the assessment of predation risk. The diet-dependent shift in anti-predator behavior within the nocturnal cycle also suggests temporal variation in the chemical cues used for risk assessment.},
	booktitle = {Chemical {Signals} in {Vertebrates} {X}},
	publisher = {Springer},
	author = {Sullivan, Aaron M and Madison, Dale M and Maerz, John C and Rohr, J R},
	year = {2005},
	keywords = {amphibian, behavioral biorhythms, chemical alarm cues, predation},
	pages = {349--356},
}

The effects of predator diet on prey anti-predator responses to chemical cues may be crucial to understanding predator-prey interactions. In this study we examined how predator diet influenced red-backed salamander (Plethodon cinereus) responses to chemical traces from garter snakes (Thamnophis sirtalis) fed red-backed salamanders and northern two-lined salamanders (Eurycea bislineata) at two different periods of their active cycle. During early evening (around sunset), P. cinereus avoided all predator chemical traces regardless of snake diet, with neither treatment being avoided more than the other in treatment comparisons. Late at night, only the chemical traces from snakes fed P. cinereus elicited avoidance, even when treatments were tested against one another. The relative avoidance of treatments late at night suggests that the chemical cues eliciting avoidance is not generalized among plethodontid salamanders, and that chemical traces of related organisms in the predator's diet may contribute to the assessment of predation risk. The diet-dependent shift in anti-predator behavior within the nocturnal cycle also suggests temporal variation in the chemical cues used for risk assessment.

@article{karuzas_alternative_2004,
	title = {An alternative hypothesis for the primary function of a proposed mate assessment behaviour in red-backed salamanders},
	volume = {68},
	copyright = {All rights reserved},
	doi = {10.1016/j.anbehav.2003.08.032},
	abstract = {Using a laboratory experiment, we tested the hypothesis that faecal inspection and squashing behaviours by female red-backed salamanders, Plethodon cinereus, function in a context other than mate assessment, in this case foraging. Because only female P. cinereus squash faecal pellets, other studies have hypothesized that the faecal squashing is a mate assessment behaviour. During the courtship season, we exposed gravid female P. cinereus maintained on a 'high-quality' or 'low-quality' diet, to the faecal pellets of male and female conspecifics fed 'high-quality' diets. Female diet had no effect on activity level, and, overall, P. cinereus showed greater interest in male-marked substrates than female-marked substrates. However, female diet had a large effect on faecal inspection and squashing behaviours, and females showed similar inspection and squashing rates towards both male and female faecal pellets. These results suggest that faecal squashing does not function primarily in mate assessment, but rather as a means for female P. cinereus to gain information about prey availability. We propose that male P. cinereus have evolved to exploit female faecal inspection and squashing behaviours (sensory exploitation) to attract foraging females into areas to increase male encounter rates with females. ? 2004 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.},
	number = {3},
	journal = {Animal Behaviour},
	author = {Karuzas, J.M. and Maerz, J.C. and Madison, D.M.},
	year = {2004},
	pages = {489--494},
}

Using a laboratory experiment, we tested the hypothesis that faecal inspection and squashing behaviours by female red-backed salamanders, Plethodon cinereus, function in a context other than mate assessment, in this case foraging. Because only female P. cinereus squash faecal pellets, other studies have hypothesized that the faecal squashing is a mate assessment behaviour. During the courtship season, we exposed gravid female P. cinereus maintained on a 'high-quality' or 'low-quality' diet, to the faecal pellets of male and female conspecifics fed 'high-quality' diets. Female diet had no effect on activity level, and, overall, P. cinereus showed greater interest in male-marked substrates than female-marked substrates. However, female diet had a large effect on faecal inspection and squashing behaviours, and females showed similar inspection and squashing rates towards both male and female faecal pellets. These results suggest that faecal squashing does not function primarily in mate assessment, but rather as a means for female P. cinereus to gain information about prey availability. We propose that male P. cinereus have evolved to exploit female faecal inspection and squashing behaviours (sensory exploitation) to attract foraging females into areas to increase male encounter rates with females. ? 2004 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

@article{maerz_plethodon_2003,
	title = {Plethodon cinereus (eastern {Red}-backed salamander) cannibalism},
	volume = {34},
	copyright = {All rights reserved},
	journal = {Herpetological Review},
	author = {Maerz, John C and Karuzas, Jeremiah M},
	year = {2003},
	pages = {46--47},
}

@article{lamoureux_pre-migratory_2002,
	title = {Pre-migratory autumn foraging forays in the green frog, {Rana} clamitans},
	volume = {36},
	copyright = {All rights reserved},
	abstract = {Observations on post-breeding movements of radio-implanted green frogs (Rana clamitans) revealed that frogs made repetitive forays away from and back to breeding ponds before final migrations to overwintering sites away from the pond. We used a drift fence and radio-transmitters to test the hypothesis that these movements were related to preoverwintering foraging and not overwintering site selection. Movements were oriented directly to habitats away from the pond, the terrestrial habitats had more food than those closer to the pond edge, and frog mass increased during forays away from the pond but declined at the pond. Foray directions were not correlated with migration direction and were considerably shorter than migration distances to overwintering sites. An intense, late season, foraging period is probably necessary for the green frog to rebuild lipid reserves following breeding and to prepare for overwintering.},
	number = {2},
	journal = {Journal of Herpetology},
	author = {Lamoureux, Victor S and Maerz, John C and Madison, Dale M},
	year = {2002},
	keywords = {Anura, Rana, amphibian, foraging, frog, migration},
	pages = {245--254},
}

Observations on post-breeding movements of radio-implanted green frogs (Rana clamitans) revealed that frogs made repetitive forays away from and back to breeding ponds before final migrations to overwintering sites away from the pond. We used a drift fence and radio-transmitters to test the hypothesis that these movements were related to preoverwintering foraging and not overwintering site selection. Movements were oriented directly to habitats away from the pond, the terrestrial habitats had more food than those closer to the pond edge, and frog mass increased during forays away from the pond but declined at the pond. Foray directions were not correlated with migration direction and were considerably shorter than migration distances to overwintering sites. An intense, late season, foraging period is probably necessary for the green frog to rebuild lipid reserves following breeding and to prepare for overwintering.

@article{sullivan_anti-predator_2002,
	title = {Anti-predator response of red-backed salamanders ({Plethodon} cinereus) to chemical cues from garter snakes ({Thamnophis} sirtalis): {Laboratory} and field experiments},
	volume = {51},
	copyright = {All rights reserved},
	doi = {10.1007/s00265-001-0434-2},
	abstract = {Recent laboratory studies show that terrestrial salamanders exhibit anti-predatory behavior in response to chemical cues from predators, but no studies have confirmed these results in the field where environmental and social factors may influence responses. We examined the character and duration of anti-predator behavior of red-backed salamanders (Plethodon cinereus) exposed to control stimuli and chemical cues from garter snakes (Thamnophis sirtalis) in evening laboratory and field trials. In the laboratory, P. cinereus significantly avoided snake rinse for 36 h. In the field, P. cinereus exposed to the same cues delayed emergence from refugia for 2 h, but this response did not last to the following morning (12 h later). Individual salamanders found in groups of two or more did not show a differential response to snake cues. These data show that red-backed salamanders respond to predator cues in natural settings, and that shelter size combined with social grouping influence anti-predator behavior.},
	number = {3},
	journal = {Behavioral Ecology and Sociobiology},
	author = {Sullivan, A.M. and Maerz, J.C. and Madison, D.M.},
	year = {2002},
	keywords = {Chemical cues, Plethodon, Refuge u, [Anti-predator},
	pages = {227--233},
}

Recent laboratory studies show that terrestrial salamanders exhibit anti-predatory behavior in response to chemical cues from predators, but no studies have confirmed these results in the field where environmental and social factors may influence responses. We examined the character and duration of anti-predator behavior of red-backed salamanders (Plethodon cinereus) exposed to control stimuli and chemical cues from garter snakes (Thamnophis sirtalis) in evening laboratory and field trials. In the laboratory, P. cinereus significantly avoided snake rinse for 36 h. In the field, P. cinereus exposed to the same cues delayed emergence from refugia for 2 h, but this response did not last to the following morning (12 h later). Individual salamanders found in groups of two or more did not show a differential response to snake cues. These data show that red-backed salamanders respond to predator cues in natural settings, and that shelter size combined with social grouping influence anti-predator behavior.

@article{madison_complex_2002,
	title = {A complex, cross-taxon, chemical releasor of antipredator behavior in amphibians},
	volume = {23},
	copyright = {All rights reserved},
	url = {file:///C:/Documents and Settings/jcm63/My Documents/John C. Maerz III/LIBRARY/Madison et al 2002 JCE.pdf},
	abstract = {Prey species show diverse antipredator responses to chemical cues signaling predation threat. Among terrestrial vertebrates, the red-backed salamander, Plethodon cinereus, is an important species in the study of these chemical defenses. During the day and early evening, this species avoids rinses from garter snakes, Thamnophis sirtalis, independent of snake diet, but late at night, avoids only those rinses from garter snakes that have recently eaten P cinereus. We tested whether the selective, late-night response requires the ingestion or injury of salamanders. In three experiments, we tested P. cinereus for their responses to separate or combined rinses from salamanders (undisturbed, distressed, and injured P. cinereus) and snakes (unfed, earthworm fed, and salamander-fed T. sirtalis). When paired against a water control, only rinses from salamander-fed snakes were avoided. When salamander treatments (undisturbed or distressed) were combined with the snake treatments (unfed or earthworm-fed) and tested against a water control, the combinations elicited avoidance. When selected treatments were paired against the standard rinse from salamander-fed snakes, only the combined rinses from salamanders and snakes nullified the avoidance response to the standard rinse. These data reveal a prey defense mechanism involving chemical elements from both the predator and prey that does not require injury or ingestion of the prey in the formation of the cue.},
	number = {11},
	journal = {Journal of Chemical Ecology},
	author = {Madison, Dale M and Sullivan, Aaron M and Maerz, John C and McDarby, James H and Rohr, Jason R},
	year = {2002},
	keywords = {Plethodon, Plethodontidae, Thamnophis, amphibian, chemical alarm cues, chemical cues, predation, salamander},
	pages = {2271--2282},
}

Prey species show diverse antipredator responses to chemical cues signaling predation threat. Among terrestrial vertebrates, the red-backed salamander, Plethodon cinereus, is an important species in the study of these chemical defenses. During the day and early evening, this species avoids rinses from garter snakes, Thamnophis sirtalis, independent of snake diet, but late at night, avoids only those rinses from garter snakes that have recently eaten P cinereus. We tested whether the selective, late-night response requires the ingestion or injury of salamanders. In three experiments, we tested P. cinereus for their responses to separate or combined rinses from salamanders (undisturbed, distressed, and injured P. cinereus) and snakes (unfed, earthworm fed, and salamander-fed T. sirtalis). When paired against a water control, only rinses from salamander-fed snakes were avoided. When salamander treatments (undisturbed or distressed) were combined with the snake treatments (unfed or earthworm-fed) and tested against a water control, the combinations elicited avoidance. When selected treatments were paired against the standard rinse from salamander-fed snakes, only the combined rinses from salamanders and snakes nullified the avoidance response to the standard rinse. These data reveal a prey defense mechanism involving chemical elements from both the predator and prey that does not require injury or ingestion of the prey in the formation of the cue.

@article{maerz_effects_2001,
	title = {Effects of predator chemical cues and behavioral biorhythms on foraging activity of terrestrial salamanders},
	volume = {27},
	copyright = {All rights reserved},
	doi = {10.1023/A:1010309108210},
	abstract = {Red-backed salamanders, Plethodon cinereus, show a variety of alarm responses to chemical cues from eastern garter snakes, Thamnophis sirtalis. We measured the foraging activity of red-backed salamanders exposed to water soiled by a garter snake (fed P. cinereus) or to unsoiled water. Salamanders exposed to snake-soiled water showed less foraging activity than salamanders exposed to unsoiled water; therefore, predators could have nonlethal effects on salamander populations. Our results also show additional factors influenced salamander foraging activity. Salamander foraging activity and responsiveness to chemical cues do not appear to have been affected by sex or food deprivation. Salamander foraging activity does appear to have been influenced by activity biorhythms. Foraging activity of animals in both treatments showed a bimodal periodicity that is consistent with natural activity patterns controlled by internal biorhythms. Exposure to snake-soiled water significantly reduced foraging activity during periods of peak foraging activity, but had a subtler effect on foraging activity during natural lulls in activity. We suggest that both activity biorhythms and exposure to chemical cues are important factors affecting salamander foraging behavior.},
	number = {7},
	journal = {Journal of Chemical Ecology},
	author = {Maerz, J.C. and Panebianco, N.L. and Madison, D.M.},
	year = {2001},
	keywords = {Chemical cues, Foraging, Plethodon cin, [Biorhythm},
	pages = {1333--1344},
}

Red-backed salamanders, Plethodon cinereus, show a variety of alarm responses to chemical cues from eastern garter snakes, Thamnophis sirtalis. We measured the foraging activity of red-backed salamanders exposed to water soiled by a garter snake (fed P. cinereus) or to unsoiled water. Salamanders exposed to snake-soiled water showed less foraging activity than salamanders exposed to unsoiled water; therefore, predators could have nonlethal effects on salamander populations. Our results also show additional factors influenced salamander foraging activity. Salamander foraging activity and responsiveness to chemical cues do not appear to have been affected by sex or food deprivation. Salamander foraging activity does appear to have been influenced by activity biorhythms. Foraging activity of animals in both treatments showed a bimodal periodicity that is consistent with natural activity patterns controlled by internal biorhythms. Exposure to snake-soiled water significantly reduced foraging activity during periods of peak foraging activity, but had a subtler effect on foraging activity during natural lulls in activity. We suggest that both activity biorhythms and exposure to chemical cues are important factors affecting salamander foraging behavior.

@incollection{maerz_environmental_2000,
	address = {New York, New York, U.S.A.},
	title = {Environmental variation and territorial behavior in a terrestrial salamander},
	copyright = {All rights reserved},
	booktitle = {The {Biology} of {Plethodontid} {Salamanders}},
	publisher = {Kluwer Academic/ Plenum Publishing},
	author = {Maerz, John C and Madison, Dale M},
	editor = {Bruce, Richard C and Jaeger, Robert G and Houck, Lynne D},
	year = {2000},
	keywords = {Plethodon, Plethodontidae, amphibian, geographic variation, salamander, social behavior, territorial behavior, territoriality},
	pages = {395--406},
}

@article{madison_optimization_1999,
	title = {Optimization of predator avoidance by salamanders using chemical cues: {Diet} and diel effects},
	volume = {105},
	copyright = {All rights reserved},
	doi = {10.1046/j.1439-0310.1999.10512481.x},
	abstract = {The allocation of time and energy to predator defense is a fundamental problem for animals. Predator avoidance may decrease the risk of injury or mortality, but it may also compromise foraging or reproduction, so potential prey should decide whether to avoid a predator based on predation risk. We show that red-backed salamanders (Plethodon cinereus) discriminate between substrates chemically conditioned by garter snakes (Thamnophis sirtalis) that were fed red-backed salamanders, earthworms, or nothing. At night, individuals avoided only the conspecific treatment, and this response was independent of any individual differences between snakes. During the day when garter snakes are much more active, all treatments were avoided. This avoidance appeared to be influenced by a diel rhythm of responsiveness rather than ambient lighting. Avoidance of prey alarm substances released during predation does not explain all these results, nor can simple avoidance of predator scent. A more complex mechanism is proposed that incorporates predator recognition, predator diet discrimination, and risk assessment. These data suggest that terrestrial salamanders may use chemoreception to identify garter snakes and their diets in order to optimize predator avoidance.},
	number = {12},
	journal = {Ethology},
	author = {Madison, D.M. and Maerz, J.C. and McDarby, J.H.},
	year = {1999},
	pages = {1073--1086},
}

The allocation of time and energy to predator defense is a fundamental problem for animals. Predator avoidance may decrease the risk of injury or mortality, but it may also compromise foraging or reproduction, so potential prey should decide whether to avoid a predator based on predation risk. We show that red-backed salamanders (Plethodon cinereus) discriminate between substrates chemically conditioned by garter snakes (Thamnophis sirtalis) that were fed red-backed salamanders, earthworms, or nothing. At night, individuals avoided only the conspecific treatment, and this response was independent of any individual differences between snakes. During the day when garter snakes are much more active, all treatments were avoided. This avoidance appeared to be influenced by a diel rhythm of responsiveness rather than ambient lighting. Avoidance of prey alarm substances released during predation does not explain all these results, nor can simple avoidance of predator scent. A more complex mechanism is proposed that incorporates predator recognition, predator diet discrimination, and risk assessment. These data suggest that terrestrial salamanders may use chemoreception to identify garter snakes and their diets in order to optimize predator avoidance.

@article{madison_oviposition_1999,
	title = {Oviposition behavior in the red-backed salamander ({Plethodon} cinereus): {Implications} of suspending a clutch},
	volume = {30},
	copyright = {All rights reserved},
	number = {4},
	journal = {Herpetological Review},
	author = {Madison, D.M. and Wareing, K. and Maerz, J.C. and Lamoureux, V.S.},
	year = {1999},
}

@incollection{madison_chemosensory_1999,
	address = {New York},
	title = {Chemosensory avoidance of snake odors by salamanders: freeze and flight contingencies},
	copyright = {All rights reserved},
	url = {file:///C:/Documents and Settings/jmaerz/My Documents/John C. Maerz III/Reprints/Madison et al 1999 ChemSigsVert.PDF},
	booktitle = {Advances in {Chemical} {Communication} in {Vertebrates}},
	publisher = {Kluwer Academic/ Plenum Press},
	author = {Madison, Dale M and Maerz, John C and McDarby, James D},
	editor = {Johnston, Robert E and Muller-Schwarze, Dietland and Sorensen, Peter},
	year = {1999},
	keywords = {Plethodon cinereus, Thamnophis sirtalis, activity patterns, predation, predator avoidance},
	pages = {505--516},
}

@incollection{mcdarby_chemosensory_1999,
	address = {New York},
	title = {Chemosensory avoidance of predators by the red-backed salamander, {Plethodon} cinereus},
	copyright = {All rights reserved},
	booktitle = {Advances in {Chemical} {Communication} in {Vertebrates}},
	publisher = {Kluwer Academic / Plenum Publishers},
	author = {McDarby, James D and Madison, Dale M and Maerz, John C},
	editor = {Johston, Robert E and Muller-Schwarze, Dietland and Sorensen, Peter},
	year = {1999},
	keywords = {Plethodon cinereus, Thamnophis sirtalis, activity patterns, predation, predator avoidance},
	pages = {489--495},
}