Climatic Variables as Drivers of Pterocarpus erinaceus (Fabaceae): Distribution and the Implications of Climate Change.

Pterocarpus erinaceus is an ecologically and economically important tree species native to the Sahel region of West Africa, facing severe threats due to overexploitation, habitat degradation, and climate change. This study assesses the impact of key climatic variables on the species' current distribution and projects potential range shifts across Africa under mid-21st century climate scenarios. Using an ensemble modeling approach that combines various algorithms and utilizes 37 comprehensive climatic variables, the analysis revealed significant patterns of highly suitable habitat, concentrated primarily in West Africa. Projections under low and medium emission scenarios for 2040-2060 and 2080-2100 periods predict a reduction in climatically unsuitable areas and a potential expansion of suitable habitats, suggesting that the species may be somewhat resilient to medium-term climate changes. The primary climatic factors limiting the species' distribution were identified as the Mean Temperature of the Driest Quarter and the Climatic Moisture Index. These results underscore the species' ecophysiological dependence on specific temperature and moisture regimes. Crucially, while our projections suggest the species exhibits resilience and potential habitat expansion under medium-term climate change, its realization is contingent upon mitigating persistent anthropogenic pressures. Therefore, to ensure the species' long-term persistence and maintain the ecological integrity of the West African Savanna Biome, conservation strategies must prioritize aggressive, in situ actions focused on sustainable management, controlled harvesting, and the protection of current and future suitable habitats, rather than focusing solely on long-term climate change adaptation measures.