Detailed mapping of the landscape in a “hotspot” of forest diversity on the south coast of Bahia (Atena Editora)

Abstract

The ``Costa do Cacau``, located on the south coast of Bahia, is one of the forests stretches with great emphasis on conservation, considered a forest diversity hotspot and an endemic center for several species of fauna and flora native to the Atlantic Forest, with the stretch of most representative forest still present in northeastern Brazil. One of the peculiar characteristics of the forest cover of the landscape in the cocoa region is that it is composed of native forests in different successional stages inserted in an anthropized matrix with forest characteristics, formed by shaded cocoa and rubber plantations. Due to the high structural complexity of the mosaic, there are serious difficulties in mapping these forest categories by remote sensing, despite the strategic importance of a detailed cartography in proposing conservation strategies. In this context, aiming to fill this gap by producing a detailed map of vegetation cover and land uses on a 1:10,000 scale in two landscapes with different occupation histories and levels of anthropization, in addition to carrying out a comparative diagnosis of forest fragmentation native in two landscapes totaling 303,807 ha. The mapped surface of the northern landscape (N), most of which is located in the municipalities of Una and Ilhéus, covers 101,899.2 ha, partially protected by two Conservation Units (CUs): the Una Biological Reserve (RBU) and the Refuge of Una's Wild Life (RVSU). the mapping of the southern landscape (S) covers 201,908.4 ha inserted mainly in the municipalities of Belmonte and Mascote. The cartography was performed by visual interpretation and vectorization of high-resolution images obtained by the QuickBird, WorldView-1, WorldView-2 and RapidEye sensors and covered a surface of 303,807.7 ha. ArcMap's V-Late extension was used to calculate fragmentation and isolation indicators of patches of native forest vegetation in the medium and advanced stages of regeneration. Although both landscapes show similar fragmentation indicators, the landscape to the north, partially protected by the UCs, has larger spots and a lower degree of isolation, compared to the landscape to the south, where there is no protection.