Giant Tortoise Distribution and Abundance in the Seychelles Islands: Past, Present, and Future

Abstract The giant tortoises( Aldabrachelysor Dipsochelys) of the Indian Ocean Islandshave been in decline since the first human settlementof the islands. They retain only a single natural population on Aldabra Atoll(and possibly Ile aux Cerfs, where tortoisesare descendants of a mixture of indigenous and imported animals). Several additional wild populations are known, resulting from reintroductions to the historic range and introductions outside of that range. The historical distribution of tortoisesin Seychelles is summarized, with reliable tortoiserecords from only 4 coralline islandsand 23 granitic islandsand the status of all the wild populations reviewed. This includes the first census of the Fregate Islandpopulation. In the granitic islands, only 9 islandssupport tortoisestoday and the wild population of these islandsis estimated at 500–550 adults. In the coralline islands, tortoisesare now present on 11 islands, with a total population of over 100,000 (almost all on Aldabra). Climat...