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Current climate change models predict increases in temperature, reduced frost and more variable rainfall with increased frequency of extreme weather events such as flooding and drought. Southern Africa is expected to experience more frequent drought, and t he grassland biome expected to be significantly affected by this. A possible reduction in area of between 30 and 50% is predicted. Given the importance of the grassland biome from both an intrinsic and economic perspective this reduction could have serious economic and food security consequences. For these reasons, it is critical to increase our understanding of ecosystem processes under drought-stress and warming. In winter 2019 a rainfall exclusion and warming trial was established in a good condition mesic grassland in KwaZulu-Natal, South Africa. Rainout shelters reduced the incoming precipitation by 53% and open-topped chambers increased daytime air temperature by 2°C. Species abundance data was collected annually. Rainfall manipulation had a marginal effect on species composition, however warming resulted in reduced abundance of several common forbs and the loss of numerous forb and grass species, also reducing species richness. Simpson's diversity was unaffected. These reductions in species richness reduce the ability of the grassland to recover from climatic perturbations and thus rainfall reduction coupled with warming presents a significant threat to grassland ecosystem services.