Sacred sites, particularly in forests, often form unofficial protected areas because their biodiversity is preserved and protected by the local people looking after the sites. Here, we survey the biodiversity of the Three Sisters Cave complex, a sacred site or kaya in a fragment of East African coastal forest in south-east Kenya. We show that, despite the tiny size of this non-gazetted forest reserve, it contains many of the threatened species of both flora (121 species) and fauna (46 species) representative of Kenya's coastal forest. Following the overexploitation and widespread destruction of coastal rainforests in Kenya, such sacred sites represent key biodiversity hotspots as well as forest islands in the now largely deforested coastal plain. Other non-gazetted forest sacred sites may represent undocumented sources of biodiversity that may contribute towards conservation of this threatened coastal habitat.
