PARENT SESSION
Oral Session #33: Climate Change. Presiding: A. Peterson.
Tuesday, August 7, 2001. 1:00 PM to 5:00 PM. Hall of Ideas E.
Role of disturbance in the large-scale structure and functioning of Amazonian Ecosystems.
Moorcroft, Paul1, Hurtt, George 2, Shevlikova, Elena 1, Pacala, Stephen 1, 1 2
ABSTRACT- Natural disturbances and human land-use activities have a large impact on the st ructure, dynamics and fluxes of ecosystems at a variety of scales. As a result, ecosystems are more heterogeneous in important ways than is explained by climatic and edaphic factors. The problem of scale has been a critical impediment to incorporating these fine-scale processes into larg e scale ecosystem models. We developed a new individual-based terrestrial ecosystem model, the Ecosystem Demography Model (ED). ED predicts both aspects of ecosystem structure such as above and below- ground biomass, vegetation height and basal area, and ecosystem fluxes such NPP, NEP and evapotr anspiration from climate, soil and land-use inputs. The model consists of sub-models governing leaf-level physiology, individual plant allocation, allometry and phenology, the effects of f ire disturbances and below-ground sub-models for soil carbon dynamics and hydrology. Using a new method for scaling stochastic, individual-based models of ecosystem dynamics, it is possible to predict ED's large-scale behavior without simulating the fate of every plant individually. We are currently using ED to examine how natural disturbances and human land-use practices af fect vegetation structure and dynamics within the Amazon Basin. We are also developing a coup led version of the model that will be used to examine how fine-scale ecosystem heterogeneity affect atmospheric and hydrologic processes.
KEY WORDS: amazonia, regional-scale, distrubance, land-use