Forest fragmentation in the Sao Francisco River Hydrographic Basin, Brazil

The dynamics of forest cover in the Sao Francisco River Basin (BHRSF) can be assessed by metrics of landscape ecology. The aim of this work was to evaluate the forest fragmentation of the Sao Francisco River Basin, Brazil, through metrics of landscape ecology, and the quantification of forest cover in federal conservation units (UCs) for the Caatinga, Atlantic Forest and Cerrado biomes in the years 1997, 2007 and 2017. The mapping of forest fragments was calculated by the area and the quantity of forest fragments that were divided into the size classes: (1) small (up to 10 ha); (2) medium (between 10 and 100 ha); and (3) large (greater than 100 ha). The metrics were calculated in the Fragstats (R) 4.2 software, and three groups of metrics were used: area, shape and border. The metric fragment numbers (NP), class area (CA), average fragment size (MPS) and edge density (ED) of forest fragments from the Caatinga and Cerrado biomes at BHRSF prove that the Basin is in the process of forest fragmentation mainly in the large fragments, which had their areas reduced, and in those of medium size, which had an increase in the amount of edges. In general, the protection of forest areas in the Caatinga and Cerrado UCs is not effective in maintaining the forest cover, given the deforestation that has existed in these protected areas in the last 20 years. Measures such as payments for environmental services or forest restoration must be used by the government and society in conjunction with the creation and maintenance of protected forest areas. The Atlantic Forest was the only biome to show an increase in the forest cover and a decrease in the forest fragmentation at BHRSF. Initiatives such as the Atlantic Forest Restoration Pact and the 2006 Atlantic Forest Law may have favored this increase in the forest cover.