Biodiversity in IA toolkit
Br. Indian Ocean TerritoryMap of British Indian Ocean Territory (click to view full-size)

Background information

British Indian Ocean Territory is a small archipelago surrounded by a very large expanse of ocean. Within around 54,400km2 of ocean, lie a group of islands totalling some 60km2. More importantly, the territory contains around 4,000km2 of near-surface coral reefs, about 1.5% of the total global reef area. The nearest other land is that of the Maldives, 500km away to the north. Only one of the five islands - Diego Garcia - is inhabited, and land use is for military purposes only.

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Legislation regarding biodiversity and impact assessment

International | National
International

International Conventions regarding biodiversity protection and impact assessment:

The territory asked that the UK extend provision of the Ramsar Convention to the islands, and Diego Garcia has since been designated a Ramsar site.

National

Protected area legislation for the territory is encompassed by the following:

Further information on this legislation can be found through the legislation pages.

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Key development areas and issues

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Biodiversity interest

The key habitat of the islands is the coral reef resource. The islands lie at the very southernmost tip of the Chagos Laccadive Ridge, which stretches from the Lakshwadeep islands to BIOT across the middle of the Indian Ocean. Suggestions have been set out that BIOT reefs may act as a critical link between coral reef systems to the east and west of the ridge. The reefs around the territory are also amongst the most diverse along the Laccadive-Maldive-Chagos chain.

The seagrass beds around Diego Garcia are the only significant extent of this habitat in the Territory, and hold several fish species that are so far unrecorded elsewhere in the archipelago.

Much of the terrestrial vegetation has been cleared and/or modified since at least the 1780s, with extensive coconut plantations and other non-native species now established. A variety of non-native fauna have also been introduced, many of which have probably had a very detrimental effect on native species.

Few endemic species have been found, emphasising the likelihood that the islands are a 'stepping-stone' in the ocean, linking east and west. For instance, although 280 vascular plants are recorded, none are endemic. The marine fauna is, as might be expected, very diverse, including a relict coral (Ctenella chagius) of the Meandrinidae, a family otherwise absent from the Indo-Pacific. Fish diversity is also relatively high, with at least 770 species recorded, but only three - perhaps four - endemic species.

Terrestrial fauna is far less diverse (e.g. just 91 species of bird recorded), and again, little endemism is evident, with only endemic moth and butterfly subspecies recorded. Seabird colonies of international importance occur, and rat-free islands hold sizable populations of species declining elsewhere, such as the Red-footed Booby (Sula sula), Masked Booby (S. dactylatra) and Lesser Noddy (Anous tenuirostris).

Known non-native species on the islands are primarily plants, a situation due at least in part to lack of information, remoteness and lack of inhabitants. Cats are being controlled on Diego Garcia (the only permanently-settled island) with a view to eradication in the future. There is potential to eradicate rats on one island, to reduce pressure on seabirds and turtle hatchlings (Varnham 2006).

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Protected Areas

There are very few protected areas in BIOT, with just two categories defined in the WDPA: restricted area and strict nature reserve. In addition to these, one Ramsar site is designated, though this has no explicit legal protection (?) under existing legislation. However, isolation and military status mean that the islands act as a de facto protected area.

The designated Ramsar site is Diego Garcia, covering some 35,424ha, with a proposed Ramsar site also covering the Chagos Banks, an area of 4,000,000ha! Further information can be found here

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