Forecasting the effects of bioclimatic characteristics and climate change on the potential distribution of Colophospermum mopane in southern Africa using Maximum Entropy (Maxent)

Abstract

Global climate change is gradually altering species distribution and spatial patterns of diversity. Yet, climatic factors influencing the local distribution and habitat preferences for southern African species remain largely unexplored. As such, predicting species distribution patterns and identifying environmental covariates that promote species range expansion will be critical in developing management protocols for biodiversity protection. Maxent, a species distribution model algorithm that applies a maximum entropy machine learning technique, is used in this study to map the geographical distributions of appropriate habitats for Colophospermum mopane (J.Kirk ex Benth.) J. Léonard in southern Africa under current and future climate change scenarios. We identified the highest contributors to the modelled distributions and calculated the range changes (expansion or loss) in southern Africa for C. mopane under three Representative concentration pathways (RCPs) for the 2050s and 2070s. Our results showed that the distribution of C. mopane was mainly influenced by solar radiation, annual temperature range, and annual precipitation. We also observe that C. mopane is distributed continuously in southern Africa, from southern Angola and northern Namibia to central-southern Mozambique, with a total occurrence area of 1,281,242 km2. According to the species response curves, this species preferred habitats with annual precipitation of 130–200 mm, an annual temperature range of 22–28 °C, and elevations of about 500–1000 m above sea level. Under climate change scenarios, suitable habitat areas reduced significantly in the northern limits of the potential distribution areas while they expanded in the southern limits. Overall, the appropriate habitat areas will likely expand the least (4.08–4.46%) and decline the most (8.83–10.08%) under the extreme scenario of RCP8.5, depending on the year. Although there is a lack of consensus on the range changes in future distributions among the various RCPs, it is clear that solar radiation will significantly limit the distribution of C. mopane. This knowledge is important for landscape planners and rangeland managers working to safeguard biodiversity from extinction.