Estrutura da paisagem em ambientes com diferentes altitudes no semiárido pernambucano

Abstract

Natural environments are changing dramatically. The degradation of native vegetation in the region of Araripe, located in Sertão Pernambucano, was in exploration of the exploitation of the wood and the conversion of the native vegetation in different uses. Thus, the present study aimed to analyze a structure of the forest landscape of fragments at different heights in the region of Araripe, mapping land uses and cover and evaluating as structural structures of the landscape. To investigate the environmental situation of the region, data were collected from three different environments at different heights: Baixada, Encosta and Chapada. For each environment, three areas were selected, totaling nine, which are distributed among the municipalities of Araripina, Exú and Ipubi. The analyzes were based on data obtained locally and by RapidEye images acquired in the year 2014, processed and classified. For the analysis of the landscape, the measured metrics were of area, density, shape and proximity. The results of land use and land cover mapping indicated that in the relationship between forest cover and the different uses, the class that most influenced was Agriculture, it is believed that as a consequence of the local economy is based on subsistence culture. It was verified that the environments Baixada and Encosta were the environments that presented areas with non-forest matrices, causing an imbalance in the ecological processes. When assessing the quantifications of the Forest class in the environments, it was verified that the heights gradient may influence the density of native vegetation. The analysis of the landscape revealed a high representativity of remnants smaller than five hectares, showing very fragmented landscapes. The Chapada environment was considered the least fragmented, since it presents landscapes with fewer fragments when compared to the landscapes of other environments, besides the Forest class behave like the matrix in the landscapes, increasing the connectivity between the forest patches and aiding in the gene flow. Possibly this is due to legislation to protect these areas by virtue of altitude. These results may point to differences in the fragmentation and conservation of native vegetation associated with the heights gradient. In addition, in the region a conversion of the continuous forest fragments into small and disconnected fragments takes place. However, these fragments are essential in decreasing the insulation between the spots. Thus, for a continuity of the vegetation found in the region and in the mentioned research, are actions of management and recovery of areas of permanent preservation for an improvement of the integration of the landscape.