Map of Tristan da Cunha (click to view full-size)
Background information
Together with Ascension Island, the Tristan da Cunha group is administered by St Helena as a dependent territory. Saint Helena is the closest land to the group, 2,100km to the north. The associated islands of Gough, Nightingale and Inaccessible make up the group. The population is around 300 people.
Legislation regarding biodiversity and impact assessment
International
The Tristan da Cunha Islands are a signatory to the following international conventions:
- World Heritage Convention
- Ramsar Convention
- Convention on International Trade in Endangered Species
- Convention on Migratory Species
- Convention on Biological Diversity
- International Convention on the Regulation of Whaling
National
National legislation includes:
- The Tristan da Cunha Conservation Ordinance 2006 (as amended)
- The Tristan da Cunha Fisheries Limits Ordinance of 1968 as amended by Ordinance No.3 of 1977
The Conservation Ordinance updates and replaces the 1976 Ordinance.
Further information on this legislation can be found through the legislation pages.
Key development areas and issues
The main source of income is from inshore lobster-fishing concessions.
Biodiversity interest
The main island, Tristan da Cunha, is a volcanic cone reaching to 2060m a.s.l., with vegetation zoned altitudinally and topographically into five types. Gough Island is also mountainous, being an eroded volcanic cone which rises to 960m a.s.l., the vegetation of which is determined by climatic considerations.
The islands are notable for their endemic plant and landbird communities, and are recognised as Endemic Bird Areas by BirdLife International.
Tristan's indigenous flora is relatively poor, with about 40 flowering plant and 30 fern species recorded, and less on Inaccessible and Nightingalee Islands. Around 20 taxa are endemic to the islands. Over 100 free-living and 24 parasitic invertebrate species are known, with 8 endemic to Gough and another 14 endemic to the Territory as a whole. Some 80 marine invertebrates have been recorded, although most are found at other island groups in the South Atlantic. Six endemic landbirds are known, and Gough is considered one of the, if not the, most important seabird colonies in the world with 20 species breeding regularly - two species alone numbering several million pairs. Native mammals are restricted to cetaceans and pinnipeds, with two species of the latter - Subantarctic Fur-seal Arctocephalus tropicalis and Southern Elephant-seal Mirounga leonina. The former has about 200,000 animals, being around 65% of the world population.
Further information about the threatened and endemic species of the Tristan group can be found on this page.
Eradication programmes are in place for mice (which are predating juvenile seabirds and possibly buntings), and New Zealand flax. Other established species are primarily invertebrates, with earthworms (Lumbricus) perhaps supporting the mouse population at a higher level than otherwise normal (Varnham 2006).
Protected Areas
Gough Island, lying some 350km SSE of the main group, was designated a World Heritage Site in 1995.
The entire island group (Gough, Tristan, Inaccessible and the Nightingale group) has also been proposed as Ramsar sites, although this has yet to be formally accepted. This would mean a total area of 17,890ha. Further information can be found on the protected areas page.