Geoinformatics Application for Land Degradation Mapping in Paraty Municipality Southeast Brazil

Abstract This study identifies areas affected by water erosion in the municipality of Paraty, Rio de Janeiro, Brazil, where natural and human pressures exacerbate land degradation. To address this issue, detailed land degradation and prioritization maps were produced using the UNEP/Priority Actions Programme methodology, representing its novel application in a tropical coastal environment and integrating multi-satellite imagery with Geographic Information System (GIS) tools. The results show that while most of the municipality is stable (838.34 km²), unstable zones (51.77 km²) persist near expanding urban areas and forest margins. Urban growth and deforestation remain the main drivers of degradation, highlighting the socio-environmental vulnerability of the region. The prioritization analysis identified high-priority zones (16.45 km² unstable and 60.80 km² stable) requiring immediate conservation or restoration measures. Land-use and land-cover changes between 1985 and 2023 revealed increases in both forest (+ 1.91%) and urban areas (+ 0.5%), alongside declines in pasture and mosaic-use areas, illustrating the complex interplay between regeneration and anthropogenic pressure. Beyond technical mapping, this research provides a decision-support tool for municipal land-use planning, environmental licensing, and disaster risk reduction policies under Brazil’s Forest Code. The study demonstrates the value of combining geospatial analysis with socio-environmental approaches to promote sustainable territorial management in fragile coastal systems.