Mapeamento de fragmentos de floresta primária na zona bragantina, Estado do Pará

Abstract

Several studies concerning the Amazonian ecosystem have shown an increasing interference of anthropic action in these spaces. In this sense, the destruction of natural vegetation for economic purposes replaces the primary vegetation with various categories of secondary vegetation (capoeiras). According to the analysis of the satellite image orbit 223.061/INPE-1995, it is evident that the Bragantine Zone, which is the target of this analysis, is very fragmented, which is a basic characteristic of the landscape in this region. The objective of this study is to map primary forest fragments, specifically in the municipalities of São Francisco do Pará and Inhangapi, Pará, at the scale of 1:50 000, considering the following vegetation cover and land use classes: primary vegetation (terra firme forest fragments and riparian forest), secondary vegetation (capoeirão, capoeira intermediária and capoeira nova), agricultural crops, pastures and exposed soil. The thematic categories were established from interpretation of LANDSAT/TM5-1996 satellite images, bands 5R4G3B-1996, based on the method described by Watrin et al. The results of the unsupervised image classification showed that only 16.76% of the total area of the municipality of São Francisco (473.56 km2) is covered with primary vegetation, and in Inhangapi (471.57 km2) the fragments comprise 12.47%, distributed mainly along the rivers and streams of the region.