Evaluating the performance of a protected area network in South Africa and its implications for megadiverse countries

As a megadiverse country with three global biodiversity hotspots, a growing human population, and a rapidly developing economy, South Africa exemplifies the challenges facing modern conservation biology. South Africa has established a protected areas network which encompasses 1527 National Parks, nature reserves, wilderness areas, mountain catchment areas, and World Heritage sites. However, the contribution of South Africa's protected areas to biodiversity conservation remains poorly known as many currently protected areas were selected based on the affordability of land or simply situated on sites that were unsuitable for commercial activities, rather than on the biological diversity within them. Here, we model the distribution of >10,000 species, representing South Africa's endemic flora, to evaluate the conservation effectiveness of the current protected areas network. We show that the flora within protected areas has been better sampled than sites outside of protected areas. However, the current protected areas network fails to adequately encompass threatened taxa, many of which are found in threatened ecosystems. We identify locations that represent important conservation gaps, and we suggest that these areas should be included in future conservation planning.