Disordered conversion of vegetation committees connectivity between forest fragments in the Brazilian Legal Amazon

Abstract

Accelerated and disordered conversion of forests into the agricultural frontier areas of the Brazilian Legal Amazon in the last four decades resulted in a fragmented landscape. Connectivity and maintenance of biodiversity in the remaining forest fragments are compromised. In this work, we evaluated landscape connectivity between the municipalities of Sorriso with a predominantly developed agricultural sector and the municipality of Alta Floresta with well-developed livestock farming. Both municipalities are located in the northern region of Mato Grosso state. We used scenes from the Landsat-8 satellite OLI (Operational Land Imager) of the year 2017 to quantify the amount of forest fragments. Six forest distances were stipulated in five size classes. Connectivity metrics of the forest fragments and landscape structure were calculated. The study area comprised 8,964 forest fragments, of which 6,149 fragments were devoted to livestock and 2,815 - to agriculture. The study results indicate that connectivity is based on long distances, which are unfavorable to mobility of the organisms. The best obtained connectivity values were 10,000 m in the areas of agriculture and 5,000 m for the livestock, respectively. The best areas for agricultural connectivity were represented by large, practically isolated fragments. In livestock areas, large fragments also had the highest connectivity values. However, smaller fragments in these areas also contributed to increased connectivity, unlike smaller fragments in agricultural areas. This research evidences the need to include environmental planning, that takes into account the forest remnants connectivity, in light of future legalized deforestation and as a way of maintaining biodiversity.