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United States Department of Agriculture

Agricultural Research Service

Title: Carbon and Nutrient Flow Through Multiple Trophic Levels in a Co2-Enriched Southern Pine Forest Community

Authors
item Rogers Jr, Hugo
item Davis, Micheal - UNIV. SOUTHERN MISS.
item Pritchard, Seth - COLLEGE OF CHARLESTON
item Prior, Stephen
item Runion, George
item Gjerstad, Dean - AUBURN UNIVERSITY
item Schlesinger, William - DUKE UNIVERSITY

Submitted to: Technical Report
Publication Type: Other
Publication Acceptance Date: April 16, 2004
Publication Date: April 16, 2004
Citation: Rogers Jr, H.H., Davis, M., Pritchard, S., Prior, S.A., Runion, G.B., Gjerstad, D., Schlesinger, W. 2004. Carbon and nutrient flow through multiple trophic levels in a co2-enriched southern pine forest community. Southeastern Regional Center, National Institute for Global Environmental Change, Annual Report for Fiscal Year 2003. The University of Alabama, Tuscaloosa, AL. 15 pp.

Interpretive Summary: We are studying the effects of elevated atmospheric CO2, through changes in leaf litter quality, on soil organisms in the southeastern U.S. Climate driven changes in litter quality and microhabitat may affect soil detritivores and how they influence carbon flow between the litter and the soil interface. Early results suggest that litter microhabitat at the Duke Forest study area is unaffected by elevated CO2. Chemical indicators of litter dietary quality also showed little affect of CO2 enrichment. Feeding trials, however, indicate that climate-induced changes in litter chemistry may exist, but mainly for defensive compounds. Early results on soil fauna abundance and diversity at the Duke Forest CO2 site suggest that diversity is not affected by high CO2, but changes in species composition did occur. Results from a CO2-enriched cropping system study at the National Soil Dynamics Laboratory did showed significantly greater species richness under high CO2 conditions. This research will continue to focus on a part of the carbon cycle that has been previously overlooked.

Technical Abstract: We are investigating the effects of elevated atmospheric CO2 on the physical and chemical properties of forest litter and the subsequent impacts on the soil fauna of southeastern ecosystems. Climate driven changes in litter dietary quality and microhabitat can affect detritivore communities and their ability to mediate carbon and nutrient flow through the soil-litter interface. Preliminary data, however, indicate that the physical characteristics of litter microhabitats at the Duke FACTS-1 site are largely unaffected by elevated CO2. Chemical parameters associated with litter dietary quality, such as tannin content and C:N, were either enhanced or unaffected by CO2 enrichment, depending on the season or tree species. Earlier feeding trials with bioassay detritivores, indicated that climate-induced changes in litter chemistry may exist, but mainly for qualitative defensive compounds such as alkaloids. Initial data on soil fauna abundance and diversity at the Duke FACTS-1 site indicate that that overall diversity is not affected by elevated CO2. Nevertheless, shifts in species composition did occur within soil fauna communities. Soil faunal data from a CO2-enriched agroecosystem study showed significantly greater species richness in CO2-enriched treatments. Currently, we are processing our second set of soil fauna samples from the Duke FACTS-1 site (5 total sets). In addition we have recently finished processing our first set of samples from the Oak Ridge FACE site and the USDA-ARS OTC site in Auburn, AL (4 and 5 total sets, respectively). This research focuses on an aspect of the carbon cycle that has been neglected. When complete, we will have the most thorough data set on soil faunal response to CO2 enrichment in existence.

Last Modified: 7/31/2014