Saint Helena consists of an administrative centre, Saint Helena Island, and two dependencies, Ascension Island and the Tristan da Cunha archipelago. These islands are separated from one another by several thousand kilometers, thus they are different in terms of climate, fauna and flora.

The remoteness of these islands has resulted in a biodiversity characterized by a high level of endemism. For example, on Saint Helena Island there are 45 endemic plants, 400 endemic invertebrates and more than a dozen endemic coastal fish species. Birdlife includes such species as the endemic Saint Helena Plover (Charadrius sanctaehelenae).

Ascension Island is home to remarkable insular fauna and flora with 35 endemic species, including the especially threatened Ascension Frigatebird (Fregata aquila). It also has one of the most important populations of breeding Green Turtles (Chelonia mydas) in the world.

The Tristan da Cunha archipelago supports five globally threatened seabirds, including the vulnerable Spectacled Petrel (Procellaria conspicillata), which is endemic to Inaccessible Island, and the endangered Atlantic Yellow-nosed Albatross (Thalassarche chlororhynchos). The archipelago is also home to four endemic land bird species, including the Tristan Thrush (Nesocichla eremita) and the Inaccessible Rail (Atlantisia rogersi), the world’s smallest flightless bird. Two endemic species of terrestrial birds the Tristan or Gough Moorhen (Gallinula nesiotis) and the Gough Bunting (Rowettia goughensis) and 12 species of endemic plant can be found on the archipelago's Gough Island.

Since 1995, the Gough and Inaccessible Islands are a UNESCO World Natural Heritage site. Read more