MODELO PARA IDENTIFICAÇÃO DA QUALIDADE DE FRAGMENTOS DE VEGETAÇÃO NATIVA: ESTUDO DE CASO DA BACIA DO RIO PIRACICABA /MG

Abstract

Fragmentation impacts biodiversity in the sense of its reduction on structural, taxonomic and functional levels of organization, as well as genetic, specific and ecosystemic. Despite of possible triggering natural causes, this process is intensifying by means of anthropogenic action. Natural habitats have been transformed into landscape mosaics where native patches of vegetation are diluted within modified areas. Fragmentation induces the loss of habitat quality by means of, among other factors, modifying its metrics and shape, as well as boosting the environmental vulnerability. Besides of loss of habitat quality, fragmentation leads to a decrease in migration and / or recolonization of species rates. Thus, the goal of this research was to create a native vegetation fragment quality measurement model based on its metrics. To reach its goals, size, isolation and circularity index were the selected parameters. In order to obtain the metrics of fragments, ArcGis software was used. The resulting model was applied to Piracicaba river basin (MG). It was observed that major concentrations of natural land cover are located in the south, where are also found the springs of the basin main river tributaries. About 80% of land cover fragments were considered high quality ones and propitious for conservation finalities.