Plant communities and plant species diversity of four Namibian inselberg landscapes were investigated across the Nama Karoo biome to elucidate biogeographical patterns, the role of inselbergs as refugia of plant species, and environmental variables determining local and regional species patterns in inselberg landscapes. The inselbergs investigated are conservation islands with a high 're-colonization potential' and biodiversity value and contribute to regional and landscape-level species pools.