Aldabra Atoll in Seychelles

A tiny speck in the Indian Ocean, the Aldabra Atoll belongs to the Seychelles. Home to some of the most endangered species of giant tortoises in the world, this fragile marine ecosystem was named a World Heritage Site by the Unesco in 1982.

Covering 35, 000ha  and over 8m above sea-level, the Aldabra atoll lies in the Mozambique Channel, situated approximately 400km north-west of Madagascar and 680km east of the East African mainland.

A classic coral atoll, the Aldabra rises from the ocean floor and is 34km long and 14.5km wide. It comprises four main islands of coral limestone demarcated by narrow passes, enclosing a large shallow lagoon. The terrain is mostly a hotch-potch of coral reef (about 125,000 years old) and ancient reef limestones. There numerous smaller islets on the lagoon and the entire atoll  is ringed by an outer reef. 

This self-sustaining ecosystem is one few areas in world where reptiles dominate the terrestrial fauna. Aldabra atoll is home to the world's largest population of giant tortoise - Geochelone gigantea - (152, 000). The Green turtle - Chelonia mydas - & Hawksbill turtle - Eretmochelys imbricata also breed here in addtion to 13 species of terrestrial birds including the last representative of the western Indian Ocean flightless birds - the endemic Aldabran white-throated rail Dryolimnas cuvieri aldabranus.

Aldabran drongo Dicrurus aldabranus (approximately 1,500 individuals) is also an endemic avian species inhabiting scrub, mangrove and casuarina enclaves on the isle-group. Aldabra is a major breeding site of the red-tailed tropical bird, Phaethon rubricauda, red-footed booby Sula Sula, greater frigatebird Fregata minor and lesser frigatebird F. ariel.

Some 178 species of flowering plants, many of which are thought to be endangered, grow on the islands. Mangrove swamp thrives at the edge of the lagoon and inshore waters support sea-grass meadows. Much of the fretted limestone terrain is covered with dense Pemphis acidula thicket, however coconut trees have been planted in isolated areas.