San Nicolas Bay Reef Islands (20854)
Aruba (to Netherlands), Caribbean
Site overview
KBA status: confirmed
Global KBA criteria: D1a
Year of last assessment: 2009
National site name: San Nicolas Bay Reef Islands
Central coordinates: Latitude: 12.4210, Longitude: -69.9030
System: marine, terrestrial
Elevation (m): 1 to 3
Area of KBA (km2): 2.48183
KBA classification: Global
Legacy site: Yes
Site details
Site description: Five small (1.75km2) low lying (max height 3m), boulder-coral reef islets located at the south-east corner of Aruba. The islands are located within San Nicolas Bay separated from the mainland by a shallow lagoon (3m-15m) adjacent to a large oil refinery and the town of San Nicolas. Hurricanes, winter storms and heavy rains have changed the size, substrate and extent of vegetative cover on the islands. Human disturbance and egg collecting has been minimized through public awareness and education. Informal protection provided by the refinery staff with regular patrols by the coastguard.
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.
Additional biodiversity: A significant regional site for Cayenne tern (1,300 – 3,500 prs.), black noddy (26-48 prs.) , roseate tern (25-75 prs.) and common tern (10-30 prs.). The site also includes sooty terns (2,000 - 6,600 prs.), brown noddy (120-180 prs.), bridled terns (3-150 prs.), least tern (5-85 prs.), and up to 10 prs of sandwich tern and royal tern. The timing of nesting is primarily between early April and mid-August, although black noddies may nest outside of this period. Non-bird biodiversity: Aruban whiptail lizards Cnemidophorus arubensis have been recorded on the islets; turtles are occasionally seen in the waters surrounding the islands; they are not known to breed on the islets. Queen conch (Strombus gigas) is relatively abundant (but not quantified) south of the San Nicolas Bay Reef Islands.
Habitats
Summary of habitats in KBA: Three of the five islands are covered with a variety of salt-resistant plants that have become more prolific in recent years. The vegetation is dominated by buttonwood (Conocarpus erecta), sea purslane (Sesuvium porlulacastrum) and bay cedar (Suriana maritme). The substrate includes sand, shell and is dominated by boulder coral.
Land use: nature conservation and research
| IUCN Habitat | Coverage % | Habitat detail |
|---|---|---|
| Forest | 33 | |
| Marine Coastal/Supratidal | 67 |
Threats
Summary of threats to biodiversity at KBA: Human disturbance by recreational visitors during April – August is the primary threat to nesting terns. A proposal for a new hotel complex within 1.5km of the islands poses a threat from water-sports enthusiasts who may venture to the islands. During nine years of intensive study there have been no significant incidents or threats from the oil refinery to the terns. Laughing gulls (Larus atricilla) represent a significant threat to nesting terns, particularly Cayenne terns, and account for 85% of egg and chick (<4–day old) mortality. Laughing gulls significantly affect overall breeding success particularly when Cayenne terns nest in small groups.
Additional information
References: AES (2006 and 2007), Bridge et. al (2005),Halewyn (1985), Voous (1983)
Contributors: We are very thankful to the author of this information Dr. Adrian del Nevo, and Theo Wools and Facundo Franken for their review.