Abstract

The objective of this research is to understand the interactive effects of changes in landuse and climate on 1) carbon storage and nutrient dynamics, including trace gas fluxes, in terrestrial ecosystems and 2) the prospect for sustainable landuse in Amazonia. The specific product of the research will be a set of coupled, hierarchically-structured models accessible through a common model framework. This framework will provide the means for investigating our principal objectives. We shall consider the LBA region within the context of two broad environmental conditions: 1) natural ecosystems where perturbations in biogeochemical states are driven primarily by natural variability of climate and fire, and 2) disturbance gradients that are induced by human landuse activities and/or human-induced climate change.

We will use our models of terrestrial biogeochemical cycles, vegetation dynamics, hydrology and landuse change. We will concentrate on model improvements to ensure applicability of all models to the LBA study region. The ecosystem and hydrology models will be driven by the physical climate, whereas the landuse model will be driven by biophysical, ecological and economic constraints. The linked models (Fig. 1) will be incorporated into a Geographic Information Systems (GIS) context, accessing numerous data sets from LBA or data layers housed at our institutions. We will evaluate model performance by comparison with field measurements from LBA as well from published data sources. We will use satellite remote sensing analysis as a means to evaluate the spatial and temporal patterns of model performance at the regional scale. Finally, we will apply formal statistical methods to characterize model uncertainty, as we apply this work to the question of the human impacts on the Amazonian landscape.

Change from both natural and anthropogenic sources must be appropriately understood. Therefore, we will focus on three objectives: 1) the natural pattern of variability in net primary production, respiration, nutrient availability, and the flux of trace gases between terrestrial ecosystems and the atmosphere; 2) human-altered landcover and ecosystem distribution and condition; and 3) the associated changes in the pattern of net primary production, respiration, nutrient availability, and the flux of trace gases between terrestrial ecosystems and the atmosphere. We recognize that this research proposal is ambitious. The effort will draw significant support from our EOS IDS grant and other currently funded activities. Table F.1 (in Section F) summarizes this support. Our effort will be supported by other agencies and institutions, including the MIT Joint Program on Policy and Global Change, the Oak Ridge National Laboratory DAAC, and the University of Texas (Dr. J. Famiglietti). Section J includes letters of support from these outside collaborators.