Identifying biodiversity knowledge gaps for conserving South Africa’s endemic flora

As a megadiverse country with a rapidly growing population, South Africa is experiencing a biodiversity crisis: natural habitats are being degraded and species are becoming threatened with extinction. In an era of big biodiversity data and limited conservation resources, conservation biologists are challenged to use such data for cost-effective conservation planning. However, while extensive, key genomic and distributional databases remain incomplete and contain biases. Here, we compiled data on the distribution of South Africa’s > 10,000 endemic plant species, and used species distribution modelling to identify regions with climate suitable for supporting high diversity, but which have been poorly sampled. By comparing the match between projected species richness from climate to observed sampling effort, we identify priority areas and taxa for future biodiversity sampling. We reveal evidence for strong geographical and taxonomic sampling biases, indicating that we have still not fully captured the extraordinary diversity of South Africa’s endemic flora. We suggest that these knowledge gaps contribute to the insufficient protection of plant biodiversity within the country—which reflect part of a broader Leopoldean shortfall in conservation data.