The invertebrate fauna of the sandstone caves of the Cape Peninsula (South Africa): patterns of endemism and conservation priorities

The temperate sandstone caves of the Cape Peninsula, South Africa, support 85 cavernicolous invertebrate species across six phyla. Six of these, including two blind and depigmented species of insects (Dermaptera) and spiders (Araneae: Hahniidae) were previously unknown. Twenty-one species are endemic to the Peninsula. Thirteen of these are presumed troglobitic Gondwanan relicts, including highly specialized, phylogenetically unique, rare species with restricted distributions and specialized habitat requirements. According to the criteria listed in the IUCN Red List Categories (1994), the onychophoran Peripatopsis alba and crustacean Spelaeogriphus lepidops should be considered Critically Endangered, their extents of occurrence being less than 100 km2. Furthermore, Data Deficient species, such as the freshwater shrimps Protojanira leleupi and Paramelita barnardi, the spider Hahnia sp.nov., the earwig Dermaptera sp.nov. and the centipede Cryptops stupendus, are likely to be additional Critically Endangered species on account of their exceptional rarity or restricted distributions. The remaining endemic cavernicoles are considered Endangered on account of their limited distributions (extent of occurrence <5000 km2). Therefore, conservation considerations are clearly an urgent priority and appropriate recommendations are provided. Management-orientated research, long-term population monitoring and the conservation of pseudokarst areas, are urgent requirements for the conservation of these rare and threatened evolutionary relicts in their isolated island-like habitats.