Biosphere reserves in the megadiverse Cape Floristic Region are effective in conserving arthropod diversity

Abstract Biosphere reserves (BRs) aim to protect global biodiversity alongside social and economic development. Each BR is composed of a core area where biodiversity conservation is maximal. Surrounding this zone is a buffer and then a transition zone where agroecological farming and other low‐intensity land‐uses are undertaken to an increasing degree. The Cape Floristic Region (CFR) is a biodiversity hotspot at the southern tip of Africa, extremely rich in endemic plants and arthropods. We review the instigation of four CFR BRs for effective conservation to protect this unique biodiversity, and where new species are regularly being discovered. Core areas protect many endemic and rare arthropod species with impacts from human activities in these critical areas being softened by the outer zones. Within the buffer and transition zones, agroecological approaches are advancing arthropod conservation, largely through maintenance of natural patches in the agricultural matrix. While larger patches are better, small patches also have high value for arthropods, especially when functionally connected. Other biodiversity‐friendly farming methods such as high vegetation cover between vine rows are also proving to be effective for indigenous arthropod conservation, as is an ecologically sensitive pest management strategy. Furthermore, a national programme aimed at removal of invasive alien trees is enabling arthropod recovery, especially endemic stream insects. Although fire is a natural CFR phenomenon, increased fire frequency is of concern. Nevertheless, natural fire refuges remain vitally important and are playing a critical role, especially for vulnerable species‐rich groups like pollinators. Overall, there is optimism that most arthropod species will remain at effective population levels in this megadiversity hotspot by putting in place effective precautionary measures. Here we show that the BR model contributes towards the protection of the CFR's endemic arthropod fauna, with potential to expand the BRs beyond the four official reserves.