Saint Helena is a British possession in the South Atlantic Ocean. It is a remote volcanic tropical island 1,950 kilometres west of the coast of south-western Africa, and 4,000 kilometres east of Rio de Janeiro in South America. It is one of three constituent parts of the British Overseas Territory of Saint Helena, Ascension and Tristan da Cunha.
Saint Helena has long been known for its high proportion of endemic birds and vascular plants. The highland areas contain most of the 400 endemic species recognised to date. Much of the island has been identified by BirdLife International as being important for bird conservation, especially the endemic Saint Helena plover or wirebird, and for seabirds breeding on the offshore islets and stacks, in the north-east and the south-west Important Bird Areas. On the basis of these endemics and an exceptional range of habitats, Saint Helena is on the United Kingdom's tentative list for future UNESCO World Heritage Sites. Artist Rolf Weijburg produced various etchings on Saint Helena, picturing various of these endemic birds.
Saint Helena's biodiversity, however, also includes marine vertebrates, invertebrates, fungi, non-vascular plants, seaweeds and other biological groups. To date, very little is known about these, although more than 200 lichen-forming fungi have been recorded, including nine endemics, suggesting that many significant discoveries remain to be made.
Various flora and fauna on the island have become extinct. Due to deforestation, the last wild endemic St Helena olive tree, Nesiota elliptica died in 1994, and by December 2003, the last cultivated olive tree died. The native St.Helena earwig was last seen in the wild in 1967.
A large reforestation project has been under way since 2000 in the north-eastern corner of the island, known as the Millennium Forest, to recreate the Great Wood that existed before colonisation.
The island's shoreline is deep and is known to have abundant red crab. In 1991, a crab-fishing vessel, Oman Sea One, which was engaged in potting of crabs, capsized and later sank off the coast of Saint Helena on its way from Ascension Island, losing four crew members. One crew member was rescued by RMS St Helena.