MAPPING THE DISTRIBUTION AND HABITAT SUITABILITY OF THE CRITICALLY ENDANGERED Aubregrinia taiensis IN GHANA

Aubregrinia taiensis is a rare and critically endangered tree species with a highly restricted native range distribution in Ghana, Côte d’Ivoire, and Liberia. In this study, we present a detailed spatial analysis of the distributions of A. taiensis across range countries in West Africa. Habitat Suitability Models (HSMs) for the species were developed using the machine-learning maximum entropy (Maxent) method. Bioclimatic environmental variables from the WorldClim database were used to simulate the future distribution of the species based on two greenhouse gas emission scenarios (RCP 4.5 and RCP 8.5) for 2050 and 2070. Our results confirm the species' narrow and highly fragmented population. The current range of A. taiensis in Ghana is estimated as 65,123.78 km2, spanning the upper limits of the south-western wet-evergreen forest, to the lower portions of the forest-savannah transition zone. Four main bioclimatic variables, Bio 10 (mean temperature of warmest quarter), Bio 1 (annual mean precipitation), Bio 5 (maximum temperature of the warmest month), and elevation, were found to influence the occurrence and suitability of A. taiensis. Further, our models indicated significant range contractions of 76.4% and 89.6% under both emission scenarios. By 2070, climatic changes could push the species to the brink of extinction. Specific conservation interventions are proposed. Keywords: biodiversity hotspots; endangered flora; climate change impacts; habitat modeling; Maxent.