A dynamic model of patterns of deforestation and their effect on the ability of the Brazilian Amazonia to provide ecosystem services

This paper presents a dynamic systems model that shows how different land use patterns degrade the value of ecosystem services provided by the Brazilian Amazonia. The model consists of four sectors: (1) deforestation drivers; (2) land use/cover; (3) ecosystem services; and (4) ecosystem valuation. The deforestation drivers sector models the economic and social incentives that small farmers and large pasture investors have for clearing the forest. The land use/cover sector shows how these different groups clear land, and further shows how patterns of forest succession and associated biomass differ by primary land use type. Different land use patterns greatly impact the quality and economic value of ecosystem services. These impacts are dealt with in the ecosystem services sector, which models the region's hydrological cycle, the nutrient cycle, carbon sequestration capacity, and species diversity. Calculations are made in the ecosystem valuation sector according to a reference monetary value for these ecosystem services. The model calculates the change in these values according to the land use practices that occur over time. Findings show that over a 100-year simulation, forest area remains about 44% of original area with pasture and abandoned pasture becoming the dominant land cover, The value of ecosystem services declines from $1431 to $658 and $781 ha(-1) year(-1) for agriculture and pasture, respectively. These findings are compared to annual revenue derived from different land use practices for which land was cleared in the Brazilian Amazonia. In the context of these findings, the authors discuss how an explicit monetary valuation of ecosystem services could create positive incentives for land stewardship and conservation. (C) 2001 Elsevier Science BN. All rights reserved.