Anthropogenic activities have increasingly pressured biodiversity worldwide. The cactus Melocactus pachyacanthus, an endemic and endangered species of Brazil´s Caatinga biome, is particularly vulnerable. This study assessed the effects of climate change, land use, and fire on the distribution of M. pachyacanthus across three ecoregions in the Chapada Diamantina region, Bahia, Brazil. We employed Ecological Niche Modeling (ENM) to evaluate current climatic suitability and to project future scenarios, overlaying ENM outputs with land-use and fire data. The current model identified a concentration of suitable habitat in the Southern Sertaneja Depression. At the same time, future projections reveal a reduction in this region and an expansion toward the Chapada Diamantina Complex. Although land use significantly contributed to habitat loss, fire had a lesser impact. Our findings underscore the importance of ENM as a tool for identifying priority conservation areas and guiding the creation of Environmental Protection Areas. These results highlight the urgent need for conservation policies to safeguard endemic species like M. pachyacanthus amid ongoing environmental changes. Our research provides insights into how climate and human activities reshape species distributions in semi-arid regions worldwide.