Monitoring Land-Use Change in Tropical Rainforests

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One of the most active areas of human-environmental interaction in recent years has been the rainforests of the Amazon Basin. Rapid deforestation and expansion of agricultural and other human activities has dramatically altered large tracts of land. The resultant change in plant cover has profound implications for flows of carbon between terrestrial and atmospheric systems, not only in Amazonia, but across the globe. Recent models of climatic change have considered deforestation an irreversible process, but analysis of satellite imagery over the last 15 years indicates that processes are much more complex. This project will develop and test analytic procedures to analyze changing patterns of land use, land cover, and related variables in a part of Zona Bragantina, the first part of Amazonia to be extensively settled. Data from the LANDSAT Thematic Mapper will be used to identify land-use and land-cover patterns; these data will be entered into a geographic information system (GIS) with data on political boundaries and jurisdictions, river and road networks, and major geologic and soil features. The GIS will then be used to analyze the dynamics of deforestation and subsequent human settlement, the degree to which pastures and fields are abandoned, and the rates of natural revegetation. These analyses may well show that large tracts of cleared forest land return to a densely vegetated state at much faster rates than previously understood. The research will be conducted collaboratively with scientists from the Brazilian Organization for Ranching and Agriculture (EMBRAPA). NSF support has been complemented by funds from the U.S. Agency for International Development, which will be used to purchase computer equipment and supplies for use by EMBRAPA in this project. This research project will provide a highly instructive examination of procedures that can be used to evaluate relationships between infrastructure and economic development and land-use changes in a heavily forested part of the Amazon basin. By relating human activities to natural processes in this region, the investigator should establish a framework for more extensive examination of human- environmental interactions. Among the interactions that can be more effectively examined are processes by which human-induced land use affects the diversity of biological species. This line of research should also help establish a firmer basis for evaluating the nature and magnitude of various policies that have been proposed for reducing natural environmental stress while encouraging economic development. The results of this project will be highly generalizable in other nations.