Tromelin (6769)
French Southern Territories, Antarctica

Site overview

KBA status: confirmed

Year of last assessment: 2014

National site name: Tromelin

Central coordinates: Latitude: -15.8920, Longitude: 54.5230

System: marine, terrestrial

Elevation (m): 0 to 7

Area of KBA (km²): 1.0899

KBA classification: Regional

Legacy site: Yes

Site details

Site description: The site is a remote islet in the western Indian Ocean, roughly 480 km north-north-west of Mauritius and 390 km east of the Masoala Peninsula, Madagascar. The islet is low, flat and coralline. The native vegetation is in good condition, composed of Tournefortia argentea thicket and 3–5 species of herb. The island is an unmanned Nature Reserve, but has a meteorological station with four permanent staff. It is frequently affected by cyclones.

Rationale for qualifying as KBA: This site qualifies as a Key Biodiversity Area of international significance that was identified using previously established criteria and thresholds for the identification of Important Bird and Biodiversity Areas (IBAs) and for which available data indicate that it does not meet global KBA criteria and thresholds set out in the Global Standard. KBA identified in the CEPF Ecosystem Profile of the Madagascar and Indian Ocean Islands Hotspot (2014). Taxonomy, nomenclature and threat status follow the 2013 IUCN Red List.

Additional biodiversity: Two seabird species nest, both boobies (Sulidae). During 1993–1996, 200–250 pairs of Sula dactylatra nested (with up to 700 birds present, and increasing), alongside 130–180 pairs of S. sula (up to 500 present, declining). These populations comprise less than 1% of the global populations, but the site is considered to be an Important Bird Area for the following reasons: first, Sulidae populations in the western Indian Ocean have declined seriously and these are among the healthiest in existence; second, S. dactylatra is represented in the western Indian Ocean by an endemic race (S. d. melanops), of which Tromelin is one of the strongholds; and third, the S. sula population at Tromelin is the only polymorphic one in the region, indicating uniqueness and biogeographical isolation. Fregata ariel became extinct before 1968 and F. minor in the early 1980s, but up to 120 Fregata spp. use the island for roosting. Resident landbirds are absent. Non-bird biodiversity: The islet is a nesting site for the sea-turtle Chelonia mydas (EN).

Delineation rationale: Type 1 marine IBA: suitable for the seaward extension approach.

Habitats

Land use: nature conservation and research

Threats

Summary of threats to biodiversity at KBA: The islet was made a Nature Reserve in 1975. Classification as a Strict Nature Reserve by Arrêté Ministériel is needed to improve the site’s protection (see ‘Conservation infrastructure and protected-area system’). Tromelin is an important research site. Human disturbance to the seabird colony is minimal. Rattus norvegicus have been abundant and are a limiting factor to seabird populations, but are controlled periodically (although never eradicated) by poisoning.

Additional information