Aride Island Special Reserve (6781)
Seychelles, Africa

Site overview

KBA status: confirmed

Global KBA criteria: B1, D1a

Year of last assessment: 2014

National site name: Reserve Spéciale de l'Ile Aride

Central coordinates: Latitude: -4.2110, Longitude: 55.6670

System: marine, terrestrial

Elevation (m): 0 to 135

Area of KBA (km²): 2.11666

Protected area coverage (%): 100.00

KBA classification: Global

Legacy site: Yes

Site details

Site description: Aride (68.3 ha) is the most northerly of the granitic islands, lying 9 km north of Praslin and 45 km north-east of Mahé. The site also includes 105 ha of coastal marine habitat. A ridge of Precambrian granite, rising to 135 m, dominates a small plateau of 9 ha. There is a single beach 800 m long on the southern side of the island while the rest of the coastline is composed of cliffs and rocky shore. The island is densely covered with mixed native woodland dominated by Pisonia grandis, Ficus lutea and F. reflexa. Granite outcrops and open glades are abundant on the hill, where there are also smaller areas of Euphorbia pyrifolia scrub. A young, managed woodland, replanted with indigenous species (Callophyllum inophyllum, Terminalia catappa, Morinda citrifolia, etc.), and a small wetland, are present on the plateau. Human activities are limited to nature conservation, research and ecotourism (day visits and confined to main paths only). Most of the former coconut plantation has been progressively eliminated and the only remaining agricultural activity is restricted to a small garden for resident staff. Coral reefs surround the island.

Rationale for qualifying as KBA: This site qualifies as a Key Biodiversity Area of international significance that meets the thresholds for at least one criterion described in the Global Standard for the Identification of KBAs. 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. The following KBA trigger species occur at this site but are not yet available in WBDB, either because they have only been globally Red-List-assessed recently (in 2012-2013; global Red List category is given in brackets, where triggering the Vulnerability KBA criterion) or because they have not yet been globally Red-List-assessed (most of these taxa are nevertheless listed as valid in Catalogue of Life or Tropicos); many of the latter species may prove to be globally threatened, or are already listed as regionally or nationally threatened, and nearly all of the following species are also likely to be endemic to the Hotspot, often with very restricted known ranges, thus also triggering the Irreplaceability 1 KBA criterion: PLANTAE: Peponium vogelii.

Additional biodiversity: See Box and Table 2 for key species. With approximately one million breeding seabirds of 10 species, Aride island holds one of the most important seabird colonies of the Indian Ocean. In addition to the tern species listed below, 71–89 pairs Sterna anaethetus also breed. Aride also hosts the largest known population in Seychelles of Puffinus lherminieri nicolae and is the most northerly breeding site for Phaethon rubricauda (3–5 pairs). Important numbers of Puffinus pacificus also occur from September to March. Seabird numbers are largest during the south-east monsoon, from May to October, the breeding season for many species. However, Phaethon lepturus, Gygis alba, Puffinus lherminieri and Sterna anaethetus may nest all year-round. Mixed, non-breeding flocks of Fregata minor and F. ariel are regularly seen roosting or soaring over the island (up to 4,600 birds between November and February). Landbirds include Acrocephalus sechellensis, originating from 29 birds introduced from Cousin in 1988. With a minimum of 1,600 birds present in 1997, the majority of the world population now occurs on Aride. Several attempts to re-establish a breeding population of Copsychus sechellarum have not so far succeeded (one pair still present in 2001). Nectarinia dussumieri (min. 49 birds) and Alectroenas pulcherrima (min. three pairs) have recolonized the island naturally. Streptopelia picturata picturata (200–400 birds) and Gallinula chloropus (200–400 birds) are also present. Non-bird biodiversity: There are eight resident reptile species, of which seven are endemic (including Mabuya wrightii and M. seychellensis at extremely high densities). Among the large invertebrate fauna, the whip scorpion Phrynicus scaber is present in good numbers. The turtles Eretmochelys imbricata (CR) and, occasionally, Chelonia mydas (EN) nest on the beach. Of the 100 vascular plants recorded on the island, Rothmannia annae is now restricted to Aride, as may be the Peponium sp. (taxonomy uncertain).

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

Habitats

Land use: hunting | nature conservation and research | tourism/recreation

Threats

Summary of threats to biodiversity at KBA: Aride was purchased by Christopher Cadbury in 1973 on behalf of the RSNC to be managed as a wildlife sanctuary. It was declared a Special Nature Reserve by government in 1979 and its boundary extends 200 m offshore. The reserve is funded through sponsorship, tourism and an endowment fund. The island is rat-free and although mice are present their impact is thought to be minor. The management plan includes the future re-establishment of other endemic species historically present, including Terpsiphone corvina and Coracopsis nigra barklyi. Aride has the longest continuous bird-monitoring programme of any island in Seychelles. Research programmes (e.g. on Sterna dougallii, Phaethon lepturus and Acrocephalus sechellensis) are conducted by the island staff and graduate volunteers in collaboration with different conservation bodies and universities. A Tyto alba eradication programme is in progress. Colonization of the island by alien predators, especially rats, is the main threat. Poaching of seabirds, including of eggs, for food and for sale still occurs and may be significant.

Additional information