Habitat suitability modeling for the conservation and cultivation of the multipurpose fruit tree, Balanites aegyptiaca L., in the Republic of Chad, Sahel

Balanites aegyptiaca, a key agroforestry species, is being overexploited in the Sahel due to increasing market demand for its derived products. The present study aims to model the potential current distribution of B. aegyptiaca and to assess the potential impact of the future climate (at 2055 and 2085 time horizons) on the species distribution in Chad to identify suitable areas for its further domestication. The principle of maximum entropy (MaxEnt) was used. Species occurrence data combined with bioclimatic data from the AFRICLIM database resulted in ten reduced general circulation models (GCMs) using five regional climate models (RCMs) under the RCP8.5 scenario. The results showed that the rainiest month (BIO13) and the number of dry months (dm) contributed the most to the models' prediction. GCM and RCM models predicted a slight decrease (22.8%) by 2055 and a significant increase (92%) by 2085 in the extent of suitable areas for B. aegyptiaca cultivation. Thereafter, a slight decrease (27.8%) by 2055 and a relatively large extension (56.40%) by 2085 in the extent of suitable areas for its conservation through protected areas were noted. Our findings revealed the conversion of parts of unsuitable areas for the species cultivation and conservation into very suitable areas by 2085. This suggests that further domestication of B. aegyptiaca will be possible over a large part of Chad (46%) in the context of changing climates. These findings should support policy-makers in making reliable decisions toward sustainable management of desert date in the Sahel.