Spatial distribution of <Emphasis Type="Italic">Vachellia karroo</Emphasis> in Zimbabwean savannas (southern Africa) under a changing climate

Climate change projections in southern Africa show a drier and a warmer future climate. It is not yet clear how these changes are going to affect the suitable habitat of bush encroacher woody species in southern African savannas. Maximum Entropy niche modelling technique was used to test the extent to which climate change is likely to affect the suitable habitat of Vachellia karroo in Zimbabwe based on six Global Climate Models (GCMs) from Coupled Model Intercomparison Project Phase 5 (CMIP5) and two Representative Concentration Pathways (RCPs) for the 2070s. An overlay analysis was then performed in a Geographic Information System based on the current and future bioclimatically suitable areas for the respective GCMs and RCPs. This was done to determine the potential effect of climate change on the focal species. Results show that temperature related variables are more important in explaining the spatial distribution of V. karroo than precipitation related variables. In addition, results indicate an overall increase in the modelled suitable habitat for V. karroo by the 2070s across the GCMs and RCPs considered in this study. Specifically, the suitable habitat of V. Karroo is projected to increase by a maximum of 57,594 km² signifying a 69% increase from the current suitable habitat (83,674 km²). The suitable areas are projected to increase in eastern, western and south eastern parts of Zimbabwe. These results imply that improved understanding of the response of woody species to a changing climate is important for managing bush encroachment in savanna ecosystems.