A new paper published in the journal Biodiversity and Conservation models the current and future ranges of montane plant species in South Africa and Lesotho - and finds a contraction in species ranges towards higher elevation in response to climate warming.
The modelled responses of plants used in this study show a decline in potential distribution as climate changes, and therefore suggest potentially increased vulnerability. This is a cause for concern for these southern African regions which are high in biodiversity and endemism. ABSTRACT
Global climate change is a major challenge for the future with serious potential impacts on biodiversity. Biodiversity in mountains is particularly vulnerable as many montane species are adapted to narrow microhabitats, making them less able to adjust to a climatic change. Investigating range changes in the South African Great Escarpment is of significance to due the high levels of biodiversity in these mountains, as well as their importance for water provision in South Africa.
The current and future ranges of 46 montane plant species in South Africa and Lesotho were therefore modelled using biomod in R, using presence points and predictor variables which included rainfall and temperature worldclim layers. The performance of distribution models produced was evaluated using the Area Under the Receiver Operating Curve (AUC), True Skill Statistic (TSS), and Sensitivity and Specificity. The researchers calculated beta diversity and species richness changes between current and future climates for the group of 46 species, as well as shifts of the predicted presence region boundaries and centroids. Shifts in minimum, median, and maximum elevations were also analysed.
The results show a contraction in species’ ranges towards higher elevation, as has been documented from other mountain regions around the world. These results are a cause for concern as a warming climate is decreasing the potential regions of occurrence of montane species in South Africa and Lesotho’s mountainous regions of high biodiversity. This region is under a diverse range of conservation and land use management practises, and the results suggest a coordinated response to climate change is needed.