Climate change impact on the niche dynamics of <i>Diospyros crumenata</i> , a critically endangered tree species in Western Ghats–Sri Lanka biodiversity hotspot

Climate change is one of the major reasons for biodiversity decline. Due to a changing climate, trees experience shrinking and shifting of ecologically suited areas, which ultimately leads to population loss and even extinction. A recent global assessment of trees indicates that nearly 40% are at extinction. Diospyros crumenata Thwaites (Ebenaceae) is a critically endangered tree species, endemic to the evergreen and semi-evergreen forests of the Western Ghats-Sri Lanka biodiversity hotspot. This tree species, which is economically and ecologically important, is facing serious threats in its natural habitat and needs immediate conservation measures. The current work sought to comprehend D. crumenata's distribution pattern and habitat appropriateness under present and future climate change scenarios (2050 and 2070) using MaxEnt. The research also aimed to determine the main environmental factors influencing the distribution of D. crumenata. We used 19 bioclimatic variables and other topographical variables including elevation, slope, aspect, and soil data for predicting the current and future potential distribution of the species. Along with this, we used three different global climate models -HadGEM3-GC31-LL, MICROC6, and BCC-CSM2-MR, for 2050 and 2070, using four SSP scenarios for predicting the future distribution of species. An area under the curve value of 0.926 indicated that the MaxEnt modelling performed exceptionally well in forecasting the distribution of D. crumenata. We found that precipitation of the wettest month, followed by elevation, precipitation of the driest quarter, precipitation of the driest month, and precipitation of the wettest quarter are the most significant variables.