Siberut Biosphere Reserve

UNESCO Biosphere Reserve, inscribed 1981, in Indonesia. Siberut is the largest of the four Mentawai Islands situated off the west coast of Sumatra. It has been isolated from the Sumatra mainland and the Sunda Shelf for at least 500,000 years, resulting in an exceptionally high degree of endemism. Sixty-five per cent of the animals are thought to be endemic. Lowland dipterocarp rainforest is the principal ecosystem.