Key Biodiversity Areas

Virgin Islands National Park (20735)
Virgin Islands (to USA), Caribbean

Site overview


KBA status: confirmed
Year of last assessment: 2009
National site name: Virgin Islands National Park
Central coordinates: Latitude: 18.3318, Longitude: -64.7457
System: marine, terrestrial
Elevation (m): -22 to 390
Area of KBA (km2): 60.36645
Protected area coverage (%): 98.85
KBA classification: Global/Regional TBD
Legacy site: Yes

Site details


Site description: St. John is the smallest of the U.S. Virgin Islands with 28 square miles, 53% (7,000 acres) of which is the Virgin Islands National Park. Most of the landscape is second growth with relatively few introduced plant and bird species. Diverse habitats include rocky and sandy coastlines, semi-arid thorn-cactus communities, a comprehensive assortment of tropical dry forest formations from coastal hedge to shrublands and canopied upland forests, moist forests, mangrove wetlands, freshwater and saltwater ponds, small agricultural/pasture lands, and small towns. The island receives an average of 44 inches of rainfall annually, but is highly seasonal, with the heaviest precipitation occurring from August to November, augmented by a late-spring wet period. The winter-spring dry season normally lasts 3 months or more.
Rationale for qualifying as KBA: This site qualifies as a Key Biodiversity Area of international significance because it meets one or more previously established criteria and thresholds for identifying sites of biodiversity importance (including Important Bird and Biodiversity Areas, Alliance for Zero Extinction sites, and Key Biodiversity Areas)
Additional biodiversity: A total of 120 bird species have been confirmed on St. John. Key waterbird species are itemized in Table 1. Widespread terrestrial species include Red-tailed Hawk, American Kestrel, Scaly-naped Pigeon, White-crowned Pigeon, Zenaida Dove, Bridled Quail Dove, Common Ground Dove, Mangrove Cuckoo, Smooth-billed Ani, Green-throated Carib, Antillean Crested Hummingbird, Belted Kingfisher, Caribbean Eleania, Gray Kingbird, Puerto Rican Flycatcher, Black-whiskered Vireo, Caribbean Martin, Barn Swallow, Northern Mockingbird, Pearly-eyed Thrasher, Northern Parula, Yellow Warbler, Prairie Warbler, Blackpoll Warbler, Black and White Warbler, American Redstart, Northern Waterthrush, Bananaquit, Black-faced Grassquit, and Lesser Antillean Bullfinch. Among the wood warblers, only the Yellow Warbler (Dendroica petechia) is a nesting resident in the Virgin Islands. The White-crowned Pigeon (Columba leucocephala), listed by Birdlife International as “near threatened” nests in coastal mangroves and forests. Non-bird biodiversity: Green Turtles (Chelonia mydas) and Hawksbill Turtles (Eretmochelys imbricata) have been seen on St. John beaches and may nest. The Virgin Islands tree boa (Epicrates monensis granti) is listed as endangered by the VI Dept. of Fish & Wildlife. A number of endangered plant species have been identified on St. John including Eugenia earhartii (Earhart's eugenia), Solanum conocarpum (Marron baccora), Agave eggersiana (Eggers' agave), Erythrina eggersii (Eggers' cockspur), Machaonia woodburyana (Woodbury's machaonia), Calyptranthes thomasiana (St. Thomas lidflower), Zanthoxylum thomasianum (St. Thomas Prickly ash).
Delineation rationale: Mark has the shapefiles.

Habitats


Summary of habitats in KBA: St. John has remarkably diverse documented wetlands habitats including at least 28 salt ponds, 20 mangrove areas, 41 beaches, 15 major seagrass areas, and 31 areas of nearshore coral reefs. The woody species of the mangroves are Red Mangrove (Rhizophora mangle), Black Mangrove (Avicennia germinans), White Mangrove (Laguncularia racemosa). Mangrove areas around salt ponds and fringing the coastline provide vital nesting habitat for pigeons, hummingbirds, and herons. Other wildlife (lizards, crabs, juvenile fish) depend on mangroves for feeding, resting, and escape from predators. Beaches around St. John vary in elevation and size between winter and summer, providing essential habitat for crustaceans, sea turtles, terns, gulls, and shorebirds. They are often associated with important nearshore seagrass beds and salt ponds inshore. Human disturbance can be extreme on certain popular beaches and the National Park has attempted to restrict access to selected strands during tern nesting season. The numerous salt ponds exhibit variations in salinity and provide diverse habitats for a variety of algae, aquatic and littoral invertebrates. These conditions generate a vital food source for both resident and migratory birds including Black-necked Stilts, Yellow Legs, Spotted and Semipalmated Sandpipers, White-cheeked Pintails, coots, kingbirds, and swallows. Upland habitats include moist, semi-evergreen forests, dry deciduous forests, thorn woodlands, and coastal scrublands. These habitats consist of botanically rich and diverse native species assemblages. The forests are important habitats for predominantly indigenous communities of avian species and winter habitat for neotropical migrants, including more than 20 species of warblers. Although most of the National Park is subject to low human use/disturbance, the campgrounds, beaches, trails, and archeological sites have regular visitation and are subject to varying degrees of human disturbance. Moreover, there are more than 250 private in-holdings within the authorized boundaries of the Virgin Islands National Park.
Land use: nature conservation and research | tourism/recreation
IUCN HabitatCoverage %Habitat detail
Marine Coastal/Supratidal14
Marine Intertidal14
Forest14
Shrubland14
Grassland14
Marine Neritic29

Threats


Summary of threats to biodiversity at KBA: Most current land use and development outside the National Park is oriented towards tourism, public recreation, and resort development rather than conservation or restoration. Development outside the Park boundaries has been intense and continues to threaten valuable habitats. Introduction of exotic landscaping pests, mostly invertebrates, but including fungal and viral pathogens, are attacking native plant species and they are becoming a significant concern to conservationists. Imported nursery stock of plants native to the islands are a rising genetic threat. Also, some invasive exotic plants are included in the international nursery trade in recent years, causing habitat decline locally. Disturbance of soil stabilizing vegetation on slopes above the nearshore sea grass beds and coral reefs has resulted in erosion and sedimentation. Coral reefs have been negatively affected by this sedimentation. Reefs show signs of bleaching as well. Coastal mangroves are critical to the shoreline stabilization and filtering of slope runoff and are under growing threat from invasive plants (Sweet Lime, etc.) where disturbance and openings have occurred. Introduced terrestrial pest species of major concern that are subject to controls include mongoose (Herpestes javanicus) , domestic cats, donkeys, key deer, pigs, goats, sheep, and rats. The Park has had some success with reducing the feral donkey population. St. John is exposed to the sea so there is a natural threat from tropical storms and tsunamis that could damage the beach, mangroves, or forests. Maintenance and increased restoration of the mangrove wetlands, coral reefs, and beach area vegetation is vital to stabilizing and protecting these areas for both human enjoyment and wildlife habitat.

Additional information


References: Boulon, R.H. and D. M. Griffin (1999); McLaughlin, M.(Eds)(1976);Platenberg et al. (2005); Raffaele et al. (2003);Raffaele, H. (1989).