Tristan da Cunha

Tristan da Cunha is the most remote inhabited island in the world and is 2,778 km west of Cape Town at 37o 06’S and 12o 18’W. The island is volcanic and 98 km2 in area. It has one settlement, Edinburgh of the Seven Seas, which is the only inhabited part of the island. The Group also includes Nightingale, Inaccessible and Gough Islands. Nightingale Island has an area of 3.2 km2 and is 38 km southwest of Tristan at 37o 24’S and 12o 29’W. There are two associated small offshore islands, Stoltenhoff and Middle (or Alex) Islands as well as offshore islets and stacks. Inaccessible Island is 1.4 km2 in area and lies 40 km southwest of Tristan at 37o 18’S and 12oW. Gough Island is 350 km SSE of Tristan at 40o 21’S and 09o 53’W with an area of 65 km2. Whilst Nightingale and Inaccessible Islands are both uninhabited Gough Island contains a permanent meteorological station at Transvaal Bay. Average temperatures at Tristan range from 12oC in August-September to 19oC in February. Average annual rainfall is 1 681 mm. At Gough Island temperatures range between about 6oC and 17oC and average annual rainfall is over 3 000 mm.

The islands were originally discovered by the Portuguese Admiral Tristao da Cunha in 1506 en-route to Cape Town. The first recorded landing of Tristan was by the Dutch in 1643 and there were two subsequent Dutch expeditions before they abandoned the idea of using it as a permanent supply base. In 1816 the UK formally took possession of the island when HMS Falmouth established a garrison there. The next year a small group led by Thomas Glass settled the island permanently. They were joined by others over the years, including five female volunteers from Saint Helena, and by 1832 the population had risen to 34. Various travails and periods of isolation meant that when a communications base was established during World War Two the island experienced a major transformation. This brought new buildings and some cash into the economy. Between the war and 1961 Tristan experienced a booming economy due to the establishment of a successful fishing industry to exploit the crawfish and the agreement to the establishment of a meteorological base on Gough Island by the South African Government. As part of the lease agreement for Gough the RMS Agulhas makes an annual supply visit to Tristan from Cape Town.

During October 1961 a volcanic eruption led to the entire population of 264 islanders and 26 expatriates being evacuated, firstly to Cape Town and then to Southampton in the UK.  Although initially the UK Government assumed that the evacuation would be permanent the islanders pressed for repatriation.  After a favourable report from a Royal Society expedition in 1962 the islanders returned to re-establish the settlement in late 1963.  

The population Of Tristan da Cunha is now about 260.  The economy is based on traditional subsistence farming and fishing supplemented by royalties from the commercial crawfishing industry, the sale of stamps and coins and income from limited tourism.

Biodiversity

The Kew database has 53 species of native flowering plants for the Group of which 28 species and 4 sub-species are regarded as endemic. There are also 38 species of ferns and clubmosses, of which 15 species and 2 subspecies are regarded as endemic. Seven of the endemic species are restricted to one island in the Group, mainly Gough Island. Terrestrial invertebrates are less well studied although over a hundred species have been recorded, including eight that are endemic to Gough Island and another 14 endemic to the Group. Only eight species of freshwater invertebrates are known. At least 79 species of littoral invertebrates have been recorded and 20 coastal species of fish. The Tristan rock lobster (Crawfish) Jasus tristani is a major element of a local commercial fishery which brings income to the Islands.

There are no native reptiles, amphibians or land mammals. The islands are of major ornithological significance and contains 14 species of global concern. There are six endemic land birds; the Inaccessible Rail Atlantisia rogersi, Tristan Thrush Nesochicla eremita, Tristan Bunting Nesospiza acunhae and Grosbeak Bunting Nesospiza wilkinsi are endemic to the main Tristan group whilst the Gough Moorhen Gallinula comeri and Gough Bunting Rowettia goughensis are endemic to Gough Island. Four species of breeding seabirds are endemic to the islands – the Tristan Albatross Diomedea dabbenena, Atlantic Yellow-nosed Albatross Thalassarche chlororynchos, Spectacled Petrel Procellaria conspicillata and Atlantic Petrel Pterodroma incerta.

Policy/Strategy background

Tristan da Cunha 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 Tristan Cunha 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.

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 1995 Gough Island and the surrounding waters out to three nautical miles was declared a World Heritage Site and the site was extended to include Inaccessible Island and the surrounding waters out to 12 nautical miles in 2004. In October 2010 a Gough and Inaccessible Island World Heritage Site Management Plan was produced by the RSPB and Tristan Conservation Department.


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