CAUSES AND EFFECTS OF LAND-USE CHANGE IN CENTRAL RONDONIA, BRAZIL

Land-use change is one of the major factors affecting global environme ntal conditions. Modeling land-use change requires combining spatially explicit ecological information with socioeconomic factors. A modelin g system has been developed that integrates sub-models of human coloni zation and ecological interactions to estimate patterns and rates of d eforestation under different immigration and land management scenarios . The simulation modeling system is being applied to the Brazilian sta te of Rondonia where deforestation has increased at a faster rate over the past two decades than anywhere else in the world. The model proje ctions suggest that appropriate land management can both reduce carbon release and improve the length of time farmers are able to remain suc cessfully on the land. The model provides a tool to evaluate the impli cations of various land management options. Analysis of field intervie ws with farmers from central Rondonia indicates that the model does re present much of the land-use dynamics as well as points out aspects of the system where the model needs improvements. Together, the model an d data suggest that land-use changes in central Rondonia are a functio n of lot size, land-use history, initial soil and vegetation condition s, land-use choices (planting annual, perennial, or pasture), market c onditions, and effects of illness on work.