Seminar: Drivers of Spatial Patterns and Long-Term Dynamics in an Arid Biodiversity Hotspot of Southern Africa

The Succulent Karoo biome in western South Africa is a globally recognized hotspot of biodiversity and endemism, with approximately 30% of its plant species being endemic. Vegetation is primarily dominated by leaf-succulent dwarf shrubs, with annuals and geophytes filling open spaces during the southern hemisphere spring. The region's high biodiversity is largely attributed to its low but predictable seasonal (winter) rainfall and pronounced habitat heterogeneity. For over thirty years, I have studied the ecological and evolutionary drivers of species and plant life-form diversity in the Succulent Karoo and adjacent arid regions of southern Africa. My research investigates how small-scale variations in soil conditions influence alpha and small-scale beta diversity, revealing that soil heterogeneity may drive high species turnover at a distance of less than 1 m. Preliminary studies also suggest that habitat heterogeneity is reflected in the population genetics of plants and their endophytic fungi. Additionally, I am studying the temporal dynamics of plant populations, examining how interannual variability in seasonal weather conditions and herbivore densities affect the population dynamics and community composition. Long-term in-situ vegetation monitoring in the Succulent Karoo and the Kalahari indicates that hot and dry conditions during the dry season strongly reduce the survival of perennial plants. These findings are essential for modeling climate change impacts and guiding conservation strategies in these fragile ecosystems.