Modelling current and future potential distributions of Vachellia tortilis (Forssk.) Hayne subsp. raddiana (Savi.) Brenan var. raddiana under climate change in Tunisia

Abstract

In this study, we modelled the current and future distribution of the V. tortilis subsp. raddiana var. raddiana for the period from 2050 (RCP 2.6; RCP 4.5; RCP 8.5) to 2070 (RCP 2.6; RCP 4.5; RCP 8.5) using a maximum entropy (MaxEnt) species distribution model. Our results showed that the precipitation-associated variables had the strongest effect on the distributions of this species. Among these variables, the precipitation of driest quarter (Bio17: 31.9 of percentage contribution) was the most important variable affecting the suitability of the habitats. Under the current climate conditions, the areas of the highly suitable (>0.6) habitat for V. tortilis in the arid land of Tunisia were 1142.532 km 2 . In the year 2050 (RCP 2.6) and 2070 (RCP 2.6), the highly suitable habitat areas for V. tortilis will continue to increase and eventually reach to 3300.704 and 5181.630 km 2 , respectively. In the year 2050 (RCP 8.5) and 2070 (RCP 8.5), the highly suitable habitat areas for V. tortilis will continue to increase and eventually reach to 9614.449 and 14684.870 km 2 , respectively. With the climate change, the highly suitable habitats of V. tortilis would shift to the southeast and northeast of Bled Talah.