Saba (19913)
Bonaire, Sint Eustatius and Saba (to Netherlands), Caribbean
Site overview
KBA status: confirmed
Global KBA criteria: B1, D1a
Year of last assessment: 2009
National site name: Saba
Central coordinates: Latitude: 17.6310, Longitude: -63.2362
System: marine, terrestrial
Elevation (m): 0 to 887
Area of KBA (km2): 21.40673
Protected area coverage (%): 99.36
KBA classification: Global
Legacy site: Yes
Site details
Site description: Saba Coastline includes all areas from the waterline to 400 meters inland around the perimeter of this small island. Because Saba’s coast is composed solely of cliffs, Red-billed Tropicbirds can be found all around the island. This habitat also is appropriate for Audubon’s Shearwater, a species which is much more difficult to detect but breeds on the island. The IBA should include Rainforest Ravine, part of the proposed Saba National Land Park, the only site where nesting of Audubon’s Shearwater has been confirmed in recent decades. The only human settlements along the coast are at Fort Bay, where a dock, several buildings, a rock quarry, and landfill exist. It is also a Tropicbird research site.
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: The Saban population of Red-billed Tropicbirds has been estimated at 750-1,000 breeding pairs, meeting the requirement for more than 1% of the global estimated population (20,000). They can be found nesting around the entire perimeter of the island in coastal cliffs and xeric, rocky hills. Despite being the national bird of Saba and familiar to residents, the Audubon’s Shearwater population is much more difficult to estimate accurately due to inconspicuous nesting habits and inadequate data. Because all coastal areas are cliffs, there is a tremendous amount of potential habitat. Indeed Lee (2000) has placed the population at 1,000 individuals based on available habitat. One shearwater was found on an egg near Sulpher Mine in February 2002. No calls were heard during 10 hours of nocturnal observations in February (Collier et al. 2002). In April 2004, two hours of nocturnal call-playback resulted in one response by a shearwater near The Bottom. In May 2004, four hours of nocturnal call-playback resulted in three responses near The Bottom and 15-20 responses at Sulpher Mine. It is possible there is no peak in breeding activity, resulting in a protracted nesting period, which would further hinder population estimates. The steep topography limits accurate nest counts as well, although numbers of flying or calling adults may be used. Although these are the only known estimates, there is sufficient evidence to conclude that Saba meets the globally important criteria for Audubon’s Shearwater. Some regionally limited species can be found in pockets of habitat along the coastal zone, these include: Green-throated Carib Eulampis holosericeus, Antillean Crested Hummingbird Orthorhyncus cristatus, Pearly-eyed Thrasher Margarops fuscatus, and Lesser Antillean Bullfinch Loxigilla noctis. Non-bird biodiversity: The single endemic vertebrate is Anolis sabanus. The gecko Sphaerodactylus sabanus has a restricted range. Hunting has caused The Mountain Crab Gecarcinus ruricola to now be considered endangered on the island. The bat sub-species Natalus stramineus stramineus is endemic to Saba.
Delineation rationale: Mark has the shapefiles.
Habitats
Summary of habitats in KBA: Habitat is primarily rocky cliffs, many over 100 meters high, interspersed with grass and scrub. Land use is limited to grazing by free roaming goats and quarry work around Fort Bay
Land use: tourism/recreation
| IUCN Habitat | Coverage % | Habitat detail |
|---|---|---|
| Grassland | 25 | |
| Forest | 25 | |
| Marine Coastal/Supratidal | 50 |
Threats
Summary of threats to biodiversity at KBA: Free roaming goats cause erosion and trample nesting burrows. Introduced predators, such as rats and feral cats and dogs, consume nest contents and attack fledged birds.
Additional information
References: Augustinus, P.G.E.F., R.P.R. Mees and M. Prins. 1985. Biotic and Abiotic Components Of the Landscapes of Saba (Netherlands Antilles). Uitgave Natuurwetenschappelijke Studiekring voor Suriname en de Nederlandse Antillen 115.Collier, N.C., A.C. Brown, and M. Hester. 2002. Searches for Seabird Breeding Colonies in the Lesser Antilles. El Pitirre 15(3).Hoogerwerf, A. 1977. Notes on the birds of St. Martin, Saba, and St. Eustatius. Studies on the Fauna of Curacao and other caribbean islands 54(176):60-123.Lee, D.S. 2000. Status and Conservation Priorities for Audubon's Shearwaters in the West Indies. Pp 25-30 in Status and Conservation of West Indian Seabirds (E.A. Schreiber and D.S. Lee, eds.).Society of Caribbean Ornithology, Special Publication No. 1, Ruston, LA.Rojer, A. 1997a. Biological Inventory of Saba. Unpublished Report. Carmabi Foundation. Curaçao, Netherlands Antilles.Stuffers, A.L. 1956. The vegetation of the Netherlands Antilles. Studies of the Flora of Curaçao and Other Caribbean Islands 1(15). Van Halewyn, R. and R.L. Norton. 1984. The status and conservation of seabirds in the Caribbean. Pp 169-222 in Status and conservation of the world's seabirds (J.P. Croxall, P.G.H. Evans, and R. Schreiber, Eds.). ICBP Technical Publication No. 2 Cambridge, United Kingdom.Voous, K. H. 1955.The birds of the Netherlands Antilles. Curaçao: Uitg. Natuurwet. Werkgroep Ned. Ant.Voous, K. H.1983. Birds of the Netherlands Antilles. 2nd ed. De Walburg Pers, Zutphen, Netherlands.Walsh-McGehee, M. 2000. Status and Conservation Priorities for White-tailed and Red-billed Tropicbirds in the West Indies. Pp 31-38 in Status and Conservation of West Indian Seabirds (E.A. Schreiber and D.S. Lee, eds.). Society of Caribbean Ornithology, Special Publication No. 1, Ruston, LA.Westermann, J. H., H. Kiel. 1961. The Geology of Saba and St. Eustatius, with Notes on the Geology of St. Kitts, Nevis and Montserrat (Lesser Antilles). Uitgaven Natuur Wetenschappelijke Studiekring Voor Suriname en de Nederlandse Antillen 24, Utrecht, The Netherlands.