Integrated geoenvironmental analysis of the Gandu River sub-basin (Bahia, Brazil): interactions among landscape, water resources, and Atlantic Forest conservation

Abstract

Drainage basins are fundamental units for integrated environmental studies, as they represent complex systems in which physical, biological, and socioeconomic components establish interdependent relationships that shape landscape organization and functioning. In this context, this research aims to conduct an integrated geoenvironmental analysis of the Gandu River sub-basin, located in the municipalities of Gandu, Nova Ibiá, and Wenceslau Guimarães, in the state of Bahia, Brazil, within the phytogeographic domain of the Atlantic Forest. The investigation is based on a systemic approach, the geosystem perspective, and the principles of Landscape Ecology, considering the relationships between natural elements and forms of land use and territorial occupation. The methodological procedures involved bibliographic research, cartographic analysis, geoprocessing techniques in a GIS environment, and the preparation of thematic maps related to location, geology, geomorphology, hypsometry, slope, pedology, drainage network, land use and land cover, and the Normalized Difference Vegetation Index (NDVI). The results show that the environmental dynamics of the sub-basin are directly related to geological, geomorphological, pedological, and hydrological characteristics, which influence infiltration processes, surface runoff, and the distribution of vegetation cover. A predominance of areas associated with secondary vegetation and agroforestry systems was observed, especially the cacao-cabruca system, which is important for maintaining regional ecological connectivity. However, landscape fragmentation resulting from the expansion of agricultural and livestock activities and changes in land use represents a threat to biodiversity conservation and the stability of environmental systems. Therefore, integrated geoenvironmental analysis is a fundamental tool for supporting land-use planning strategies, water resource conservation, recovery of degraded areas, and the implementation of ecological corridors in the context of the Atlantic Forest of Bahia.