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

Land-use change is one of the major factors affecting global environmental conditions. Modeling land-use change requires combining spatially explicit ecological information with socioeconomic factors. A modeling system has been developed that integrates sub-models of human colonization and ecological interactions to estimate patterns and rates of deforestation under different immigration and land management scenarios. The simulation modeling system is being applied to the Brazilian state of Rondonia where deforestation has increased at a faster rate over the past two decades than anywhere else in the world. The model projections suggest that appropriate land management can both reduce carbon release and improve the length of time farmers are able to remain successfully on the land. The model provides a tool to evaluate the implications of various land management options. Analysis of field interviews with farmers from central Rondonia indicates that the model does represent much of the land-use dynamics as well as points out aspects of the system where the model needs improvements. Together, the model and data suggest that land-use changes in central Rondonia are a function of lot size, land-use history, initial soil and vegetation conditions, land-use choices (planting annual, perennial, or pasture), market conditions, and effects of illness on work.