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South Atlantic

The South Atlantic Hub: Ascension Island, Saint Helena, Tristan da Cunha and Falkland Islands

Four very distinct islands or islands groups reaching across the South Atlantic Ocean, Saint Helena, Ascension Island, Tristan da Cunha and the Falkland Islands span a range of climatic systems and harbour differing ecosystems. Due to the vulnerability of these island communities to invasive species, climate change and development, more measures need to be put in place to ensure the future sustainability of their ecosystems.  

South Atlantic hub website


Main characteristics of the Region

Ascension Islandpopup

The smallest of the islands, Ascension is unusual for having a high-abundance/low-diversity sub-tropical system. Generally characterised by a lack of vegetation in its lower regions, the majority of the flora that can be found there was introduced by man in an attempt to alter the climate of the island. At the highest point on the island (859m), Green Mountain National Park is unique as an almost solely man-made ecosystem containing species that are not naturally found to coexist.

St Helena

Approximately 1,125 km south-east of Ascension, St Helena has a diverse landscape with seven ecological zones which are determined by elevation and rainfall. This ranges from semi-desert in low lying areas to a small ‘cloud forest’ at the highest peaks.

Tristan da Cunha

popup A further 2,430 km south of St Helena, Tristan da Cunha is composed of four main islands, only one of which is inhabited. It has a mild but wet climate with a mixture of grassland, woodland and bracken communities. It is mostly known for its breeding seabirds, with 13 species, giving it its status as an Important Bird Area.  

Falkland Islands


To the south-west of the Atlantic Ocean, the Falkland Islands lie 480 km off the east coast of South America’s southern Patagonian coast. It is an archipelago made up of 778 islands, with East Falkland and West Falkland making up the majority of the land area. There is much similarity

between their flora and fauna and the one found on the Patagonian shelf, with 19 land habitat types recognised. The majority of the vegetation is low lying heath and feldmark, and there are no native trees on the islands.   

Overseas Territory


Location capital

Land area (km2)

Marine area (km2)

Ascension Island


7o56’S 14o25’W



St Helena

Sub-Tropical/Marine/ Mild

15o56’S 5o43’W



Tristan da Cunha

Temperate/ Oceanic

37o4’S 12o19’W



Falkland Islands

Temperate/ Marine

51°42′S 57°51′W



Socio-economic, Policy and Civil Society Context

popupAscension Island

With no native population, all inhabitants must have a work permit to be able to reside on the island. As an important military base for both the British Royal Air Force (RAF) and United States Air Force (USAF), the majority of economic activity is centred on this. There is no commercial agriculture, despite highly fertile volcanic soils, as it is cheaper to import food to the island than produce it.

St Helena

St Helena has a very slow growing population, with some mobility of residents to Ascension Island and Falkland Islands for work. The Governor of all three islands (Ascension,St Helena and Tristan da Cunha) resides here, however both Ascension and Tristan da Cunha have their own Administrators. The island is currently reliant on aid from the British Government, but with its first airport due to be opened in February 2016, the economy is slowly shifting as more business opportunities present themselves.

Tristan da Cunha

The population of Tristan varies very little as no new permanent settlers are allowed on the island. Due to its mountainous nature only a small area of land is suitable to build on, with only one town, Edinburgh of the Seven Seas. All land is owned communally and the island is relatively self-sufficient, maintaining agriculture and livestock to support the remote population. The majority of the island's income is from lobster fisheries; however a decline in demand has damaged the economy in recent years.popup

Falkland Islands

In theFalkland Islands, unlike the majority of South Atlantic OTs, land can be owned privately and full resident status can be applied for after 7 years. The primary income (50-60%) is generated from the fishing industry and approximately 25% of the population is employed by the government. With large scale marine hydro-carbon exploration set to start imminently (2014-15), impact on the local economy is to be expected.

Overseas Territory

Population size

Main economic sector

Environmental organisations

Ascension Island



Conservation Department

St Helena



Agriculture and Natural Resources Dept

Environmental Conservation Section

Nature Conservation Group

Tristan da Cunha



Fisheries Department 

Conservation Department

Falkland Islands



South Atlantic Environmental Research Institute

Falklands Conservation

Falkland Island Government Fisheries Department

Facts and Figures

Ascension, St Helena and Tristan all have a disproportionate number of endemic species in relation to their size, due to their isolation and, until relatively recently, undisturbed nature. The Falkland Islands also contain a number of endemics but due to a relative lack of research, there is potentially more to be found as it has been proven recently. A number of these endemic species have already been lost from all four of these islands since colonisation of man, including the Ascension Crake (Mundia elpenor), St Helena Hoopoe (Upupa antaios), Tristan Moorhen (Gallinula nesiotis) and Falkland Island Wolf (Dusicyon australis). The classification of species as endemics and assessment of threatened status is ongoing in each of the territories so the numbers of each will change with time.

Ascension Islandpopup

In June 2014 Ascension expanded its land based protected areas to 20% of the islands total area, including important seabird and turtle nesting sites. It is the second largest nesting area for green turtles (Chelonia mydas) in the Atlantic and it harbours the largest nesting population found in any UK Overseas Territories (OTs). Ascension is also home to two species of shrimp (Typhlatya rogersi and Procaris ascensionis) found in small anchialine pools which exist nowhere else in the world, as well as seven endemic vascular plants, one endemic seabird, 11 fish endemic to Ascension and a further 16 shared endemics with St Helena. 45 species have been officially confirmed as endemics with estimates of more, and studies to confirm them are on-going. There are current estimates of 28 endemic invertebrates and 15 bryophyte species.

popupSt Helena

St Helena has a high number of endemic species for its size, including 45 endemic flowering plants and ferns, over 400 endemic invertebrates and approximately 26 endemic bryophytes. Previously there has been a lot of focus on protection of terrestrial ecosystems with currently no enforced protection for the marine environment.

Tristan da Cunha

All land on Tristan is protected, with around 37 endemic flowering plants and fern species; however habitat restoration is ongoing due to the impact of invasive species. This process is made difficult by access problems between the islands. The Tristan islands are an Important Bird Area (IBA) due to being nesting sites for around 20 seabird species and host to three endemic genera of terrestrial birds.

Falkland Islands

The largest of the four territories, the Falkland Islands are home to 14 endemic flowering plant and fern species, 2 endemic birds and approximately 13 endemic invertebrates. Due to the difficulty to access all of the islands, there is still relatively much unknown about the biodiversity, with new species being regularly described. It is a recognised important breeding area for 22 southern ocean seabird species, with 22 designated IBAs.

Overseas Territory

No. Threatened species

No. Endemic species

No. Terrestrial protected areas

% Total land in protected area

No. Marine protected areas

% Total marine in protected areas

Ascension Island







Saint Helena







Tristan da Cunha







Falkland Islands







* Currently a proposed MPA which is in the process of being assessed/legislated

Main challenges

All four of these OTs have a distinct lack of baseline data, particularly in the marine environment which is currently afforded little to no protection in all but the Falkland Islands. As the marine areas of each island are vast in comparison with total land area, this has become a priority for future research.

Ascension Island

Mitigation of climate change impacts are extremely important to preserve important coastal habitats that are coming increasingly under threat. Containment and control of invasive species (e.g. black rats [Rattus rattus], Mexican thorn bush [Prosopis juliflora]) is important to allow restoration of habitats and to reduce predation and competition of native and endemic species.

St Helena

A lack of resources and personnel for management is one of the main challenges within St Helena; which is especially critical with the creation of their first airport (2016) and the direct and indirect impact this will have on the environment (including resource use and potential biosecurity issues). Also there is a possibility that illegal fishing is a problem due to lack of management within the marine environment.

Tristan da Cunhapopup

The main challenges facing Tristan da Cunha are illegal- and over-fishing, which impacts on habitats, marine life and bird populations. Pollution, especially marine-borne plastics, is of concern. It is believed that climate change is having negative impacts, such as on the declining Northern Rockhopper penguin (Eudyptes moseleyi) population. A real need for Marine Protected Areas (MPAs) is also perceived within the region in order to protect the marine environment against large volumes of shipping activities. Invasive species  - rodents and alien plants - are having an important negative impact on breeding birds on some of the islands.

Falkland Islands


Amongst the number of challenges facing the Falkland Islands are Invasive Alien Species (IAS) - which are   especially posing a risk to the terrestrial environment -, climate change and a lack of basic baseline data. The developing hydrocarbons industry presents a potential for future environmental problems, however, early monitoring and stringent mitigation measures (including scientific projects like the Gap Project being conducted by SAERI) are attempting to minimise the risk. 

Importance for the Region to be involved in the BEST initiative

With high biodiversity and endemicity with comparatively poorly understood environments and ecological processes, the territories within this region are ideal locations for EU BEST implementation. Collaboration with other EU Outermost Regions and Overseas Countries and Territories (ORs and OCTs) within the BEST initiative will also be very beneficial to share knowledge and expertise.

Useful links:

Maria Taylor, South Atlantic BEST III Project Officer

Dr Paul Brickle, South Atlantic hub Coordinator

South Atlantic Environmental Research Institute (SAERI) website: 

Ascension Island Government Conservation Department website:

Saint Helena Government Environmental Management Division website:

Tristan da Cunha Government website:

Falkland Island Government website: