Análise espaço-temporal da influência de rodovias na cobertura florestal em seu entorno

Abstract

Linear projects, including roads and highways, cause physical and biological changes in their implementation axis and strongly influence the dynamics of the surrounding landscape. The impacts occur at the time of the highway's implementation and continue to influence over the years, mainly in the forest cover. In this sense, understanding how the distribution of roads influences land use and land cover is important to estimate impacts on natural landscapes. This study aimed to analyze the influence of two highways on the surrounding forest cover in a subtropical forest region in southern Brazil. Two stretches of highways that differed in terms of highway structure, traffic volume, and characteristics were selected. Based on these criteria, stretches of 20 km of extension of the BR 153 and RS 420 highways were analyzed. Through the use of geoprocessing tools and data provided by the MapBiomas system, spatiotemporal maps were created from buffers every 1 km, reaching 3 km from the highway and in different years (1985 and 2019). To calculate the metrics of the fragments, the QGIS software calculator was used, where the area of each fragment, the distance from the road to the centroid, and the circularity index were measured. To analyze the means of the different sets of data for the highways and between the years, the simple analysis of variance (ANOVA) was used. To verify if there were differences in the forest area between years, the chi qui test (χ2) was performed, by applying the Statistica program. Over the years, there has been a reduction in the area of native forest and an increase in the number of planted forest, especially in the area closest to the highway. In general, the highways presented less fragmentation, larger forest area, and larger fragments, with a higher circularity index in the buffers further away from the highway. In other words, areas closer to highways tend to have greater fragmentation, less forest cover, and, as a consequence, more environmental impacts. Both highways influenced the surroundings, with greater impacts on the larger highway.