Environmental impact assessment of land use systems using emergy in Teresópolis-Brazil

This paper provides a set of indices based on emergy analysis for the C rrego Sujo basin, Teresópolis-Brazil. Encompassing natural and agricultural systems, the C rrego Sujo basin has been affected by destruction and fragmentation of natural habitats and unsustainable land use practices. The main objective is to evaluate the environmental impact of the land use systems, the load capacity and the use of natural and economic resources. The studied land use systems were: i) agriculture, ii) grassland and cattle, iii) rainforest and iv) forest in regeneration stage (fallow: 1, 2 and 3 years old). Emergy analysis integrates all flows within a system of coupled economic and environmental work in common biophysical units (solar emjoules – seJ). The main conclusions of the study are: the basin does not have dependence of purchased resources and the environmental impact is moderate; the efficiency of the basin as a system is highly positive and it represents a positive contribution to the economy; the emergy exchange ratio is moderate and; the biggest contributions to the system come from natural sources showing that the ecological sustainability is moderate to good.