1993-1998: Contrasting Successional Rates and Carbon Cycling in Eutrophic and Oligotropic Ecosystems of Amazonia (funded by NIGEC)

Description: This project is undertaking a comparative analysis of deforestation and ecological succession in the Brazilian Amazon and the role of these processes in the global carbon cycle. Two oligotrophic sites are studied in the Eastern Amazon. These three sites are contrasted to two eutrophic sites (one in the Lower Xingu basin and the other at Marajo island) studied between 1991 and 1993 with support from NSF. At each field site, the following data will be collected: (1) history of land use, (2) forest stand structure (i.e. composition, relative abundance and spatial dispersion of trees) (3) carbon content and nutrient characterization of plants and soils, and (4) climatological data to assess changes in temperature, precipitation, albedo and evaporation at sites with contrasting areal extent of deforestation. These field data will be integrated with remotely-sensed imagery of these regions. An important component in this analysis is the use of multitemporal Landsat Thematic Mapper digital data to provide a regional-scale capability for assessing successional dynamics. A carbon balance model will be developed using field data and geo-referenced to specific sites using GIS. It is necessary to extend the understanding gained at the eutrophic sites to the more common nutrient-poor regions of Amazonia if we are to understand the Amazon's contribution to global warming. Given that both eutrophic and oligotrophic sites under study are largely in the eastern Amazon, this provides a unique opportunity to examine the possible role of changes in rainfall regime on the vegetation, on species diversity (with potential high mortality of endemics with narrow ranges of adaptability to drier conditions), and on land cover.