Protected areas, land-use dynamics and regional sustainable development: Evidence from the Rio da Barra watershed (Atlantic Forest, Brazil)

Abstract

Tropical coastal watersheds face growing pressure from tourism, agriculture, and urban expansion, generating territorial conflicts that bear directly on regional planning. This study analysed land use and land cover (LULC) dynamics in the Rio da Barra watershed (460.6 km², Porto Seguro, Bahia, Brazil) between 1985 and 2021 and discussed their implications for territorial planning, regional sustainable development, and environmental governance in the Costa do Descobrimento, with particular attention to the role of the Pau Brasil National Park as a territorial protection instrument. We used MapBiomas Collection 7.1 LULC data, with an overall accuracy exceeding 88%, processed in Google Earth Engine and QGIS 3.34.12; watershed boundaries were delineated from an SRTM-derived digital elevation model and ANA hydrographic data. Native forest cover declined by 3.81 percentage points (174.4 km² to 156.9 km²) between 1985 and 2021, while pastureland expanded by 3.41 percentage points (10.8 km² to 26.3 km²); silviculture increased from 0.13 km² to 2.94 km², and urban area, absent in 1985, reached 0.15 km² by 2021. These rates of change were markedly lower than in the neighbouring, unprotected Mucugê watershed, where native vegetation loss exceeded 46% over a comparable period. The Pau Brasil National Park overlaps 70.06% of the Rio da Barra watershed, and this spatial coincidence is the most plausible factor behind its comparatively contained land-use change relative to nearby unprotected basins. The findings indicate that the proportion of a watershed under formal protection is a relevant indicator not only of landscape-level forest retention but also of territorial stability of interest to regional planning, demonstrating that protected areas constitute strategic territorial assets capable of reconciling biodiversity conservation with sustainable regional development.