A Meta-Analysis of Bird and Mammal Response to Short-Rotation Woody Crops. Riffell, S., Verschuyl, J., Miller, D., & Wigley, T. B. 3(4):313–321.
A Meta-Analysis of Bird and Mammal Response to Short-Rotation Woody Crops [link]Paper  doi  abstract   bibtex   
Short-rotation woody cropping (SRWC) refers to silvicultural systems designed to produce woody biomass using short harvest cycles (1-15 years), intensive silvicultural techniques, high-yielding varieties, and often coppice regeneration. Recent emphasis on alternatives to fossil fuels has spurred interest in producing SRWC on privately owned and intensively managed forests of North America. We examined potential bird and small mammal response at the stand level to conversion of existing, intensively managed forests to SRWCs using meta-analysis of existing studies. We found 257 effect sizes for birds (243 effect sizes) and mammals (14 effect sizes) from 8 studies involving Populus spp. plantations. Diversity and abundance of bird guilds were lower on short-rotation plantations compared with reference woodlands, while abundance of individual bird species was more variable and not consistently higher or lower on SRWC plantations. Shrub-associated birds were more abundant on SRWC plantations, but forest-associated and cavity-nesting birds were less abundant. Effects on birds appeared to decrease with age of the SRWC plantation, but plantation age was also confounded with variation in the type of reference forest used for comparison. Both guilds and species of mammals were less abundant on SRWC plantations. These conclusions are tentative because none of these studies directly compared SRWC plantations to intensively managed forests. Plantations of SRWCs could contribute to overall landscape diversity in forest-dominated landscapes by providing shrubby habitat structure for nonforest species. However, extensive conversion of mature or intensively managed forests to SRWC would likely decrease overall diversity, especially if they replace habitat types of high conservation value. [Excerpt: Conclusions] Because we found only eight studies that represented nine comparisons of different SRWC plantation types (different ages of cottonwood or poplar) to very different types of reference forest, our conclusions are tentative. Diversity and abundance of birds and mammals were lower on SRWC plantations compared with reference forests. Species responses were mixed - SRWC plantations favored shrub-associated birds while canopy/mature forest-associated birds and cavity-nesters typically favored reference forest. SRWC plantations could likely contribute to overall landscape diversity in forest-dominated landscapes by providing shrubby habitat structure for non-forest species. For example, recommendations for maximizing wildlife habitat in the Mississippi Alluvial Valley call for ≤5\,% of the landscape to be comprised of shrub/scrub habitats, which SRWC plantations could help provide [...]. However, extensive conversion of intensively managed forests to SRWC would likely decrease overall diversity, especially if they replace high conservation value habitats [...]. [\n] Although most SRWCs will likely be established on agricultural land [...], comparing diversity of SRWC to other types of forests is important for several reasons. First, SWRCs are sometimes planted on forested lands [...] and SRWC plantations may become a more prominent component of forested landscapes. Second, much of the agricultural land potentially used for SRWC may have been forested in the past, especially marginal cropland on which SRWC may be most profitable. Third, SRWCs are one of many options for afforestation efforts [...]. Fourth, SRWC plantations and other forest types are but two of many land cover options when croplands are converted (e.g. croplands converted to SRWCs are lands that can no longer be converted to forest) and in some regions marginal cropland is commonly converted to and from forest cover [...]. Thus, it is impossible to fully understand how SWRCs will increase or decrease diversity at the landscape and regional scales without SRWC vs. forest comparisons. [Geographic limitations, empirical knowledge gaps and research needs] Burger (2002) considered SRWC systems to be intermediate to forest plantations and agrosystems in terms of management inputs and implications for biodiversity. It is unknown how SRWCs differ from traditional forest plantations because existing studies did not use intensively managed forests as reference. Such comparisons need to be made because intensively managed forests cover increasing large areas in many regions, provide habitat for species of concern, and support major components of biodiversity [...]. Future studies should also compare SRWC plantations to reference forests in a similar seral stage [...] in addition to more mature, reference forests (the other studies we reviewed). These studies should be continued over the length of the rotation. Present information about diversity in SRWC plantations in the United States is limited to the upper Midwest and the Mississippi Alluvial Valley, and few studies exist for taxa other than birds. Rectifying this lack of basic information should be the top priority for research concerning diversity and SRWCs.
@article{riffellMetaanalysisBirdMammal2011,
  title = {A Meta-Analysis of Bird and Mammal Response to Short-Rotation Woody Crops},
  author = {Riffell, Sam and Verschuyl, Jake and Miller, Darren and Wigley, T. Bently},
  date = {2011-08},
  journaltitle = {GCB Bioenergy},
  volume = {3},
  pages = {313--321},
  issn = {1757-1707},
  doi = {10.1111/j.1757-1707.2010.01089.x},
  url = {https://doi.org/10.1111/j.1757-1707.2010.01089.x},
  abstract = {Short-rotation woody cropping (SRWC) refers to silvicultural systems designed to produce woody biomass using short harvest cycles (1-15 years), intensive silvicultural techniques, high-yielding varieties, and often coppice regeneration. Recent emphasis on alternatives to fossil fuels has spurred interest in producing SRWC on privately owned and intensively managed forests of North America. We examined potential bird and small mammal response at the stand level to conversion of existing, intensively managed forests to SRWCs using meta-analysis of existing studies. We found 257 effect sizes for birds (243 effect sizes) and mammals (14 effect sizes) from 8 studies involving Populus spp. plantations. Diversity and abundance of bird guilds were lower on short-rotation plantations compared with reference woodlands, while abundance of individual bird species was more variable and not consistently higher or lower on SRWC plantations. Shrub-associated birds were more abundant on SRWC plantations, but forest-associated and cavity-nesting birds were less abundant. Effects on birds appeared to decrease with age of the SRWC plantation, but plantation age was also confounded with variation in the type of reference forest used for comparison. Both guilds and species of mammals were less abundant on SRWC plantations. These conclusions are tentative because none of these studies directly compared SRWC plantations to intensively managed forests. Plantations of SRWCs could contribute to overall landscape diversity in forest-dominated landscapes by providing shrubby habitat structure for nonforest species. However, extensive conversion of mature or intensively managed forests to SRWC would likely decrease overall diversity, especially if they replace habitat types of high conservation value.

[Excerpt: Conclusions]

Because we found only eight studies that represented nine comparisons of different SRWC plantation types (different ages of cottonwood or poplar) to very different types of reference forest, our conclusions are tentative. Diversity and abundance of birds and mammals were lower on SRWC plantations compared with reference forests. Species responses were mixed - SRWC plantations favored shrub-associated birds while canopy/mature forest-associated birds and cavity-nesters typically favored reference forest. SRWC plantations could likely contribute to overall landscape diversity in forest-dominated landscapes by providing shrubby habitat structure for non-forest species. For example, recommendations for maximizing wildlife habitat in the Mississippi Alluvial Valley call for ≤5\,\% of the landscape to be comprised of shrub/scrub habitats, which SRWC plantations could help provide [...]. However, extensive conversion of intensively managed forests to SRWC would likely decrease overall diversity, especially if they replace high conservation value habitats [...].

[\textbackslash n] Although most SRWCs will likely be established on agricultural land [...], comparing diversity of SRWC to other types of forests is important for several reasons. First, SWRCs are sometimes planted on forested lands [...] and SRWC plantations may become a more prominent component of forested landscapes. Second, much of the agricultural land potentially used for SRWC may have been forested in the past, especially marginal cropland on which SRWC may be most profitable. Third, SRWCs are one of many options for afforestation efforts [...]. Fourth, SRWC plantations and other forest types are but two of many land cover options when croplands are converted (e.g. croplands converted to SRWCs are lands that can no longer be converted to forest) and in some regions marginal cropland is commonly converted to and from forest cover [...]. Thus, it is impossible to fully understand how SWRCs will increase or decrease diversity at the landscape and regional scales without SRWC vs. forest comparisons.

[Geographic limitations, empirical knowledge gaps and research needs]

Burger (2002) considered SRWC systems to be intermediate to forest plantations and agrosystems in terms of management inputs and implications for biodiversity. It is unknown how SRWCs differ from traditional forest plantations because existing studies did not use intensively managed forests as reference. Such comparisons need to be made because intensively managed forests cover increasing large areas in many regions, provide habitat for species of concern, and support major components of biodiversity [...]. Future studies should also compare SRWC plantations to reference forests in a similar seral stage [...] in addition to more mature, reference forests (the other studies we reviewed). These studies should be continued over the length of the rotation. Present information about diversity in SRWC plantations in the United States is limited to the upper Midwest and the Mississippi Alluvial Valley, and few studies exist for taxa other than birds. Rectifying this lack of basic information should be the top priority for research concerning diversity and SRWCs.},
  keywords = {*imported-from-citeulike-INRMM,~INRMM-MiD:c-13938924,~to-add-doi-URL,biodiversity,bioenergy,bird-conservation,ecology,forest-resources,mammals,short-rotation-forestry,shrubs,sustainability,trade-offs},
  number = {4}
}
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