Climate change threatens some miombo tree species of sub-Saharan Africa

Abstract

Climate change is affecting the distribution of species globally. Predicting the distribution of species under climate change is important for conservation of biodiversity. The aim of this research was to model the current distribution of miombo woodlands of sub-Saharan Africa using seventeen miombo tree species, and to project their distributions under different climate change scenarios. A maximum entropy method, Maxent, was used to model the distributions of the seventeen representative tree species, Albizia antunesiana, Afzelia quanzensis, Baikiaea plurijuga, Brachystegia bakeriana, Brachystegia boehmii, Brachystegia longifolia, Brachystegia microphylla, Brachystegia spiciformis, Brachystegia utilis, Cryptosepalum exfoliatum, Guibourtia coleosperma, Isoberlinia angolensis, Julbernadia globiflora, Julbernadia paniculata, Pericopsis angolensis Pterocarpus angolensis, and Pterocarpus rotundifolius. A total of 3 429 occurrence records, nineteen bioclimatic variables, monthly precipitation, minimum and maximum temperatures, soil characteristics and altitude were used in modeling. Distributions were hindcasted to the Mid-Holocene and forecasted to 2050 and 2070 under all four Representative Concentration Pathways (RCPs). Hindcasting showed that ranges for A. antunesiana, B. bakeriana, B. boehmii, C. exfoliatum, G. coleosperma and Pterocarpus angolensis were larger in the Mid-Holocene than they are currently, while the ranges of the other species were constricted during this period. When forecasted, range contraction was observed for nine species, A. quanzensis, A. antunesiana, B. microphylla, B. spiciformis, B utilis, C. exfoliatum, J. globiflora, Pericopsis angolensis and P. rotundifolius. Range expansion was observed in the other eight species. Range contraction was acute in 2070 under RCP8.5 for A. quanzensis (-13%), A. antunesiana (-15%) and B. microphylla (-14%). Species whose forecasted ranges contracted should be prioritized for mitigation against climate change. All species should be protected from anthropogenic threats since most are unsustainably harvested.