Ascension Island

Map of Ascension Island

About the territory

Ascension Island was first discovered in 1501 by a Portuguese seafarer, Joao da Nova Castella, but remained uninhabited until 1815 when a British naval garrison was located on the island whilst Napoleon Bonaparte was incarcerated on Saint Helena. In 1823 it was taken over by the Royal Marines and it remained under the supervision of the British Board of Admiralty until 1922 when it became a dependency of Saint Helena. From 1922 until 1964 the island was managed by the Eastern Telegraph Company (renamed Cable & Wireless in 1934). In 1964 an Administrator was appointed.

Located in the South Atlantic at latitude 7° 57’ South, longitude 14° 22’ West, Ascension Island is about 1125 km northwest of the island of Saint Helena. A volcanic island which is around one million years old it has a total land area of 88 km2. The climate is sub-tropical with temperatures ranging between 20°C and 32°C. Showers occur throughout the year with January-April being the wettest period. Annual rainfall is as much as 680mm on Green Mountain and as little as 130mm in the lowlands. There are a number of sea stacks and one small island, Boatswainbird Island, of about 5ha. The population of the Island is not permanent, and mainly made up of employees and families of the organisations working on the island. The last population census in 2016 was 806, comprising 556 St Helena citizens and 250 other nationalities. There are five settlements on the Island, including two military bases.

On 30 August 2019 the Ascension Island Marine Protected Area (MPA) was designated following a recommendation from the Island Council. The MPA covers 100% of Ascension’s Exclusive Economic Zone (EEZ), an area of over 440,000 square km, making it one of the largest MPAs in the world. Within the MPA, it is proposed that commercial fishing and mineral extraction will be prohibited, ensuring one of the highest levels of protection possible for this biodiversity hotspot.

The designation of the MPA was the culmination of many years’ of data gathering, planning and consultation to ensure that an informed decision could be made about the best approach to manage Ascension’s waters. This work was supported by the UK Government’s Blue Belt Programme, funding from Darwin Plus, EU BEST and the Great British Oceans Coalition as well as input from academic institutions and most importantly the elected Council and people of Ascension.


The National Protected Areas Order 2014, created seven new protected areas so as to conserve Ascension’s wild and plant life, including the Island’s endemic species. The six new Nature Reserves and one new Sanctuary, in addition to Green Mountain National Park, mean that 20% of Ascension’s land is protected by measures for mitigating threats to vulnerable species.

The Kew online herbarium states that there are very few native plants on Ascension Island. There are probably 25 native vascular plants of which six ferns and six flowering plants are endemic. Most are threatened with extinction.
Ascension Island has 311 recorded species of land animals including a few that are now extinct. About 95 species are considered to be native including two marine turtles, 12 seabirds and two extinct landbirds. At least 138 species were probably introduced and 78 are of dubious status. There are about 29 endemic invertebrates including three genera of arthropods. There are no native species of terrestrial reptiles, amphibians or mammals except that the island is a major breeding site for green turtles (Chelonia midas).

There are four introduced species of reptile have been recorded with two known to be widespread (Gray’s Leaf-toed Gecko (Hemidactylus mercatorius) and Weigmann’s Swift (Liolaemus wiegmanni)). There is also a record of an African Clawed Frog but it is unclear if this species has become established.

There are eleven species of breeding seabirds including one endemic species, the Ascension Frigatebird (Fregata aquila). Most seabirds are now restricted to Boatswainbird Island or the inshore stacks rather than on the mainland. There are five resident landbirds, all introduced.

Policy and legislation

Ascension Island has an Environment Charter signed jointly with the UK Government. Guiding Principle 7 is to safeguard and restore native species, habitats and landscape features, and control or eradicate invasive species. Under the associated commitment 2 the government of Ascension Island will ensure the protection and restoration of key habitats, species and landscape features through legislation and appropriate management structures and mechanisms, including a protected area policy, and attempt the control and eradication of invasive species. Implementation progress was reviewed in 2007, 2010 and 2016, Read the 2016 review report (external link).

A South Atlantic Invasive Species Strategy and Action Plan agreed by the Governments of Ascension Island, Saint Helena, Tristan da Cunha, the Falkland Islands and South Georgia and the South Sandwich Islands was published in October 2010. This set out a number of strategic aims for the South Atlantic Overseas Territories in order to develop effective prevention and response measures for invasive species and thus reduce damage to their natural heritage, communities, livelihoods and options for future development. Key actions are grouped under five objectives: (A) Building awareness and support; (B) Co-ordination, co-operation and capacity-building; (C) Prevention; (D) Monitoring, early detection and rapid response; (E) Control, management and restoration.

In 2020 a biosecurity policy, and new biosecurity legislation was enacted in Ascension, with provisions for pre-border, border and post-border regulation of invasive species.

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