Remote Sensing and Geospatial Approach for Land Degradation Risk Assessment in the Costa Verde Bay Southeast of Brazil

Abstract

This study evaluates land degradation risk in Brazil’s Costa Verde by adapting the United Nations Environment Program, Priority Actions Program Regional Activity Centre (PAP/RAC) methodology for the first time to a humid tropical coastal environment. Unlike previous applications confined to semi-arid and Mediterranean contexts, this research integrates the PAP/RAC framework with 40 years of multi-source remote sensing data (Landsat 5/8/9; 1985–2025), land use/land cover change detection, and Mann–Kendall trend analysis, a hybrid approach that has not previously been applied in this biome. The results reveal that while 87.37% of the region remains stable, 6.24% faces active degradation from sheet and rill erosion, primarily concentrated on steep coastal slopes and expanding urban-fringe zones. Land use/land cover analysis documented a 254.17% urban expansion (+58.01 km²) since 1985, coinciding with significant losses in sensitive ecosystems, including wetlands (-47.79%) and wooded sandbank vegetation (-18.40%). To validate these dynamics, a Mann–Kendall test confirmed a statistically significant increasing trend in minimum vegetation cover (p<0.01), suggesting a long-term improvement in the minimum vegetation baseline despite localized anthropogenic pressures. A multi-criteria prioritization procedure identified 58.19 km² for immediate curative intervention and 150.74 km² for preventive protection. By bridging the PAP/RAC framework with statistical trend analysis and spatial planning, this study provides a replicable framework for erosion risk assessment in urbanizing tropical zones, offering spatial outputs that directly support the Brazilian Forest Code and municipal master plans.