Modelling the current and future distribution of Okoubaka aubrevillei Pellegr. & Normand under climate change scenarios in Côte d’Ivoire

Okoubaka aubrevillei Pellegr. & Normand, listed as Endangered by the IUCN, Threatened by Aké Assi (PRE-Protected Rare Endemic list), and under CITES Appendix II (2023), is facing extinction. This study models its current and future distribution in Côte d’Ivoire to identify key environmental drivers and predict suitable habitats. Occurrence data were obtained from the GBIF database, and nineteen bioclimatic variables representing both current and future periods were used to model its potential distribution in Côte d’Ivoire. Seven algorithms (Random Forest, MaxEnt, BRT, GAM, GLM, SVM, and CART) were used, with data partitioned into 70% for training and 30% for validation to ensure robust predictive accuracy. Binary suitability maps (favorable/unfavorable) were produced from probability outputs in ArcGIS to assess habitat gains and losses under future (2050) climate scenarios. The results indicate that the potential distribution of O. aubrevillei is mainly driven by thermal variables, while hydric factors play a secondary but complementary role. The most influential predictors are bio6 (minimum temperature of the coldest month, 55.7 %), bio8 (mean temperature of the wettest quarter, 41.8 %), and bio3 (isothermality, 31.8 %), emphasising the species’ dependence on warm and moderately humid environments, with a preference for temperatures between 18-25 °C and moderate thermal variability. Hydric variables (bio11, bio14, bio15) reflect tolerance to sub-humid conditions and a minimum water requirement of 20-40 mm during the dry season. O. aubrevillei is a thermophilic species adapted to tropical environments with moderate humidity, whose ecological niche depends upon a balance between thermal stability and water availability. Currently restricted to southern forest zones, its distribution is projected to expand northward and into central regions by 2050, under both moderate and extreme climate scenarios. This potential expansion may be constrained by deforestation, habitat fragmentation, and anthropogenic pressure that affect the availability of suitable habitat.