Assessment of Variation in Land Use/Land Cover (LULC) and Greening Through the Expansion of Algaroba (Neltuma juliflora) in the Semi-Arid Brazilian Coast

The expansion of algaroba (Neltuma juliflora), an invasive exotic species widely adapted to arid and semi-arid environments, has caused significant ecological and geomorphological changes on the northern coast of Rio Grande do Norte in Brazil. This study aimed to analyze the greening process associated with the expansion of algaroba in the Rosado Dunes Environmental Protection Area (APADR) between 2004 and 2024. Images from the SPOT 5PSM, CBERS 4, and CBERS 4A satellites were used, processed by supervised classification in QGIS software version 3.38. The multitemporal analysis revealed a significant change in the landscape, with a reduction in areas of native vegetation (caatinga and restinga) and an increase in dunes and beaches, urban areas, and invasive species. The area occupied by algaroba expanded from 70 ha (0.5%) in 2004 to 435 ha (3.1%) in 2024, representing an increase of more than six times in two decades. This expansion has had direct impacts on biodiversity, sediment dynamics, and groundwater availability, in addition to compromising connectivity between the dunes and the beach environment. The results point to the need for public policies aimed at controlling invasive species and sustainably managing native vegetation, with a view to conserving biodiversity and the integrity of the coastal and semi-arid geosystems of APADR.