Frégate is the easternmost of the granitic islands. It comprises two hills reaching a maximum of 125 m and two low-lying coastal plateaus covering 26 ha. The original vegetation was almost totally cleared in the nineteenth century and replaced by agricultural plantation crops. These were abandoned and reverted to the wild after agriculture became uneconomic and now form the dominant component of the vegetation, a mixed shrub-woodland of Cocos nucifera, Cinnamomum verum, Anacardium occidentale and assorted fruit trees. Patches of mature forest dominated by Pterocarpus indicus and native Callophyllum inophyllum also occur. Rocky areas with glacis and boulders, rocky coasts with cliffs and several pristine sandy beaches contribute to the beauty of the landscape. A small, artificial marsh, created to replace one that existed before the harbour was built, is the only wetland. Frégate is privately owned and has a small, exclusive hotel served by plane from Mahé. Besides tourism, the other main activity is agriculture, both of which cover less than 15% of the island.
See Box and Table 2 for key species. Frégate is currently the major stronghold of Copsychus sechellarum and was the island on which the species survived and from where birds were later translocated to other islands. In 1999, 51 birds were present and there were 14 occupied territories. The IBA also holds one of only four populations of Foudia sechellensis, with possibly 1,000–3,000 birds. There are also high densities of Alectroenas pulcherrima (>50 pairs) and Nectarinia dussumieri (>100 pairs). Frégate also historically held large seabird colonies, but these have mostly become extinct. Anous tenuirostris and Gygis alba remain the most numerous, with small numbers of Phaethon lepturus (c.20 pairs) and Sterna fuscata (c.1,000 pairs). Sterna anaethetus and Anous stolidus breed in limited numbers on a small satellite island, L’îlot Frégate, off the south-east point of Frégate (not included in the IBA, but under the same ownership). A variety of vagrants occur on the island; Arenaria interpres (100–200 birds) is the most abundant non-breeding visitor and is found all year-round.
Non-bird biodiversity: Frégate is one of only four islands where the skink Mabuya wrightii can be found, and also supports high densities of the endemic gecko Ailuronyx sechellensis, and the snakes Lycognathophis seychellensis and Lamprophis geometricus. There is a population of the terrapin Pelusios subniger and an introduced one of Aldabra giant tortoises Dipsochelys dussumieri. Hawksbill turtles Eretmochelys imbricata (CR) nest on the beaches. Until the early 1990s, Frégate used to support what was possibly the highest density of caecilians in the world. Numbers of the two species concerned, Grandisonia alternans and Hypogeophis rostratus, have declined drastically since then. It is thought that the introduction of pigs has contributed to this. The giant tenebrionid beetle Pulposipes herculaneus (CR) and the snail Pachnodus fregatensis are found only on Frégate.
BirdLife International (2019) Important Bird Areas factsheet: Frégate island. Downloaded from http://www.birdlife.org on 21/03/2019.