Niche specificity influences gene flow across fine‐scale habitat mosaics in Succulent Karoo plants

While the tempo of diversification in biodiversity hotspots has received much attention, the spatial scale of diversification has often been overlooked. Addressing this deficiency requires understanding the drivers of population divergence and the spatial scales at which they operate in species‐rich clades and ecosystems. South Africa's Succulent Karoo (SK) hotspot provides an excellent system for such research, being both compact (ca. 110,000 km2) and home to spectacular in‐situ radiations, such as the ruschioid Aizoaceae. Here we use GBS to document genetic structure in two co‐occurring ruschioid species, at both coarse (>10 km) and fine (