Significant and Persistent Impact of Timber Harvesting on Soil Microbial Communities in Northern Coniferous Forests. Hartmann, M., Howes, C. G., VanInsberghe, D., Yu, H., Bachar, D., Christen, R., Henrik Nilsson, R., Hallam, S. J., & Mohn, W. W. The ISME Journal, 6(12):2199–2218, August, 2012.
doi  abstract   bibtex   
Forest ecosystems have integral roles in climate stability, biodiversity and economic development. Soil stewardship is essential for sustainable forest management. Organic matter (OM) removal and soil compaction are key disturbances associated with forest harvesting, but their impacts on forest ecosystems are not well understood. Because microbiological processes regulate soil ecology and biogeochemistry, microbial community structure might serve as indicator of forest ecosystem status, revealing changes in nutrient and energy flow patterns before they have irreversible effects on long-term soil productivity. We applied massively parallel pyrosequencing of over 4.6 million ribosomal marker sequences to assess the impact of OM removal and soil compaction on bacterial and fungal communities in a field experiment replicated at six forest sites in British Columbia, Canada. More than a decade after harvesting, diversity and structure of soil bacterial and fungal communities remained significantly altered by harvesting disturbances, with individual taxonomic groups responding differentially to varied levels of the disturbances. Plant symbionts, like ectomycorrhizal fungi, and saprobic taxa, such as ascomycetes and actinomycetes, were among the most sensitive to harvesting disturbances. Given their significant ecological roles in forest development, the fate of these taxa might be critical for sustainability of forest ecosystems. Although abundant bacterial populations were ubiquitous, abundant fungal populations often revealed a patchy distribution, consistent with their higher sensitivity to the examined soil disturbances. These results establish a comprehensive inventory of bacterial and fungal community composition in northern coniferous forests and demonstrate the long-term response of their structure to key disturbances associated with forest harvesting. [Excerpt: Conclusion] Our results indicate that bacterial and fungal communities, although varying greatly across soil horizons and biogeoclimatic regions, manifest significant long-term responses to OM removal and soil compaction, with distinct responses to different levels of disturbance persisting more than a decade after tree harvesting. Symbiotic and saprobic species appear to be the most sensitive microbial groups and are potential indicators for monitoring the recovery of forest systems. Long-term monitoring over the course of a forest stand rotation will be required to determine if the microbial community structure is resilient over the very long term. Given the high potential for functional redundancy within soil ecosystems, it remains to be determined if observed changes in microbial community structure predict changes in ecosystem processes and loss of soil productivity over multiple harvesting rotations, which would make such indicators invaluable forest-management tools. Future studies exploring soil processes and metabolic properties of these forest soil communities are now needed to determine the functional significance of the observed compositional effects and indicator dynamics with respect to higher-order ecological and biogeochemical processes.
@article{hartmannSignificantPersistentImpact2012,
  title = {Significant and Persistent Impact of Timber Harvesting on Soil Microbial Communities in {{Northern}} Coniferous Forests},
  author = {Hartmann, Martin and Howes, Charles G. and VanInsberghe, David and Yu, Hang and Bachar, Dipankar and Christen, Richard and Henrik Nilsson, Rolf and Hallam, Steven J. and Mohn, William W.},
  year = {2012},
  month = aug,
  volume = {6},
  pages = {2199--2218},
  issn = {1751-7362},
  doi = {10.1038/ismej.2012.84},
  abstract = {Forest ecosystems have integral roles in climate stability, biodiversity and economic development. Soil stewardship is essential for sustainable forest management. Organic matter (OM) removal and soil compaction are key disturbances associated with forest harvesting, but their impacts on forest ecosystems are not well understood. Because microbiological processes regulate soil ecology and biogeochemistry, microbial community structure might serve as indicator of forest ecosystem status, revealing changes in nutrient and energy flow patterns before they have irreversible effects on long-term soil productivity. We applied massively parallel pyrosequencing of over 4.6 million ribosomal marker sequences to assess the impact of OM removal and soil compaction on bacterial and fungal communities in a field experiment replicated at six forest sites in British Columbia, Canada. More than a decade after harvesting, diversity and structure of soil bacterial and fungal communities remained significantly altered by harvesting disturbances, with individual taxonomic groups responding differentially to varied levels of the disturbances. Plant symbionts, like ectomycorrhizal fungi, and saprobic taxa, such as ascomycetes and actinomycetes, were among the most sensitive to harvesting disturbances. Given their significant ecological roles in forest development, the fate of these taxa might be critical for sustainability of forest ecosystems. Although abundant bacterial populations were ubiquitous, abundant fungal populations often revealed a patchy distribution, consistent with their higher sensitivity to the examined soil disturbances. These results establish a comprehensive inventory of bacterial and fungal community composition in northern coniferous forests and demonstrate the long-term response of their structure to key disturbances associated with forest harvesting.

[Excerpt: Conclusion] Our results indicate that bacterial and fungal communities, although varying greatly across soil horizons and biogeoclimatic regions, manifest significant long-term responses to OM removal and soil compaction, with distinct responses to different levels of disturbance persisting more than a decade after tree harvesting. Symbiotic and saprobic species appear to be the most sensitive microbial groups and are potential indicators for monitoring the recovery of forest systems. Long-term monitoring over the course of a forest stand rotation will be required to determine if the microbial community structure is resilient over the very long term. Given the high potential for functional redundancy within soil ecosystems, it remains to be determined if observed changes in microbial community structure predict changes in ecosystem processes and loss of soil productivity over multiple harvesting rotations, which would make such indicators invaluable forest-management tools. Future studies exploring soil processes and metabolic properties of these forest soil communities are now needed to determine the functional significance of the observed compositional effects and indicator dynamics with respect to higher-order ecological and biogeochemical processes.},
  journal = {The ISME Journal},
  keywords = {*imported-from-citeulike-INRMM,~INRMM-MiD:c-13886682,~to-add-doi-URL,anthropogenic-impacts,conifers,forest-management,soil-microbial-properties,soil-resources,timber-harvesting},
  lccn = {INRMM-MiD:c-13886682},
  number = {12}
}

Downloads: 0