Format: ORAL

Vidal Junior JD1,2, Carbutt C3, Clark VR2, Plumptre AJ4, Senbeta F5, Woldemariam T6, Chapano C7, David C8, Aiah L9, Tovar C10, Lulekal E11, Uwase AS12, Kordofani M13, Kaplin B14, Antonelli A10,15,16, Pearce T10, White J10, Loeuille B10, Langa CB17, Chelene IS17, Fremout T18, Schmitt CB1

1 Universität Passau, Passau, Germany 2 Afromontane Research Unit & Department of Plant Sciences, University of the Free State, Qwaqwa Campus, Phuthaditjhaba, South Africa 3 Ezemvelo KZN Wildlife, Peter Brown Drive, Montrose, South Africa 2 Afromontane Research Unit & Department of Geography, University of the Free State, Qwaqwa Campus, Phuthaditjhaba, South Africa 4 Key Biodiversity Area, London, United Kingdom 5 Addis Ababa Herbarium, Addis Ababa, Ethiopia 6 Environment and Coffee Forest Forum (ECFF) Addis Ababa, Ethiopia 7 National Herbarium of Zimbabwe, Harare, Zimbabwe 8 University of Zambia, Lusaka, Zambia 9 Njala University Njala Campus, Njala, Sierra Leone 10 Royal Botanic Gardens, Kew, London, United Kingdom 11 Addis Ababa University, Addis Ababa, Ethiopia 12 National Herbarium of Rwanda University of Rwanda Huye campus, Huye, Rwanda 13 University of Khartoum Herbarium Al-Gama’a Avenue, Khartoum, Sudan 14 Center of Excellence in Biodiversity & Natl Res Management (CoEB), University of Rwanda, Huye campus, Huye, Rwanda 15 Gothenburg Global Biodiversity Centre, Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden 16 Department of Biology, University of Oxford, Oxford, OX1 3RB, United Kingdom 17 Herbário LMA do Instituto de Investigação Agrária de Moçambique, Maputo, Moçambique 18 Alliance of Bioversity International and International Center for Tropical Agriculture (CIAT), Rome, Italy

Mountains host some of the most diverse and vulnerable communities of plants in Africa. With the 1.5 to 5 C increase in temperature projected for the upcoming decades, it is hypothesised that plants will shift their distribution to track their environmental constraints along elevation and latitudinal gradients depending on their dispersal capacity. Responses like upslope and poleward shifts may result in accelerated rates of species turnover and amplified habitat loss in high elevations. Little is known about how such processes will transform the floristic composition of African mountains. Here, we apply a community-scale modelling approach to quantify and map how different climate change scenarios may affect species ranges and community richness of vascular plants in African mountains. Using niche models and dispersal buffers, we project the distributions of 416 species to three climate and land use change scenarios for the late century. Our comparisons between predicted ranges indicate that, without dispersal, species will lose an average of 2252% of their suitable areas, depending on the SSP. We also observed a pattern of upslope elevational shifts and higher suitability losses for species occurring in higher elevations. Higher proportional losses are projected for ferns, herbs, and shrubs than for trees, with the highest losses projected for Southern Africa and Madagascar. Our results provide novel evidence for the disproportional impact of climate change on mountains and highlight target regions and species requiring more intensive conservation efforts and reforestation strategies, which need to improve the coverage of other life forms than trees. Furthermore, our findings emphasise that the current rate of change may be too rapid for some species to track based solely on their natural dispersal capacity, and alternatives like assisted migration must be carefully considered.