Modern grass phytolith assemblages from the Maloti-Drakensberg Mountains, southern Africa

Montane grasslands dominate the Maloti-Drakensberg mountain range in southern Africa and rank among the region's most biodiverse and sensitive ecosystems. Reconstructing their long-term dynamics remains challenging, as widely used palaeoecological proxies such as pollen offer limited taxonomic resolution for distinguishing grasses. Phytoliths, microscopic silica bodies produced abundantly by grasses, offer an opportunity to resolve grassland vegetation history at finer taxonomic resolution, however interpreting the vegetation signal they provide requires regionally calibrated reference datasets. Here, we characterize the phytoliths produced by grasses across the Maloti-Drakensberg, presenting images and abundance data from 29 grass specimens spanning five major Poaceae subfamilies. Phytoliths were extracted and classified using standardized procedures, revealing distinct assemblages associated with each subfamily. Panicoideae are dominated by bilobate and cross morphotypes, Chloridoideae by saddles and rondels, and Danthonioideae by rondels. Although some morphotypes overlap across subfamilies, differences in relative abundance allow partial differentiation, most clearly between Panicoideae and the remaining subfamilies. This modern reference dataset establishes a baseline for interpreting phytolith assemblages from sedimentary records in the Maloti-Drakensberg region and comparable montane African grasslands, offering a new tool for reconstructing past grassland composition, photosynthetic pathway distributions, and vegetation responses to climatic and land-use change in southern Africa.