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Modeling Soil Organic Carbon Stocks in Spatially and Temporally Heterogeneous Ecosystems

Speaker: Frances O'Donnell, Graduate Student
Series: EEWR Brown Bag Seminars
Location: Engineering Quad E219
Date/Time: Friday, October 22, 2010, 12:00 p.m. - 1:00 p.m.

Abstract:

Field data indicate that belowground carbon stocks and fluxes in semi-arid and arid savannas are temporally and spatially heterogeneous at small scales. Stochastic soil moisture availability leads to large variations in plant litter decomposition rates at the hourly to daily scale, and the patchy vegetation structure typical of savannas leads to a strong contrast in soil carbon stocks between areas under vegetation canopies and bare soil patches. A landscape-scale, steady-state model of soil organic carbon stocks is presented that uses probabilistic descriptions of soil moisture dynamics and vegetation structure to account for these processes. The model is used to identify combinations of soil, climate and vegetation conditions for which simpler models are likely to produce biased estimates of soil carbon dynamics. Additionally, a modeling-based approach for predicting the influence of woody plant encroachment on regional soil carbon stocks is presented.