This IBA includes Great Pond to the limits of its wetland delineation and the adjoining baymouth bar on its southern edge. Great Pond is a 50 ha mangrove-fringed, saline lagoon situated on the southeastern shore of St. Croix, U.S. Virgin Islands (USVI).
Great Pond is contained on the south by a vegetated baymouth bar. The baymouth bar, approximately 1,100 m long with a maximum width of 105 m, separates Great Pond from Great Pond Bay. Pond level and area fluctuate as a result of rainfall and tidal flow. Ground water discharge and runoff from the 470 ha of hills and pastures in the upland watershed result in a large influx of fresh water into Great Pond during and following heavy rainfall. A narrow channel with a maximum depth of 1.5 m connects the pond to Great Pond Bay at the pond’s southeast corner. Salinity varies from 20 ppt, after heavy rainfall events, to more than 40 ppt (Sladen 1992). At low water levels, mudflats are exposed around much of the pond, particularly along the western border, and extend outward 30 - 100 m from the pond edge.
Mudflats are surrounded on the west and north sides by gently sloping, fallow pastures of dry grassland with mixed thorny scrub. In some areas, rainfall runoff amplified by former cattle grazing has left shallow eroded gullies and ledges where the pasture meets the mudflats. A failing barbed wire fence intersects the mudflats on the north and west sides. A Boy Scout Camp is located to the southwest.
A paved public road (Rt. 60) flanked by an electrical transmission line is separated from the east side of the pond mudflats by a narrow row of black mangroves (Avicennia germinans). Approximately 100 houses have been built in the upland watershed, primarily to the northeast.
An open fishermen’s shanty or camping kitchen and an outhouse built on the beach berm have been in use for years. When the western mudflats are not submerged, the beach and camp site are accessed by way of a temporary track along the pond’s western edge and a well worn road along the western end of the baymouth bar. A track through the southeast mudflats is used by fishermen launching small fishing boats from the shore into Great Pond Bay. Occasionally blue crabs (Callinectes sapidus) are taken from Great Pond for food. Likewise land crabs (Cardisoma guanhumi) are trapped on the baymouth bar and wetland fringes.
Like all lagoons in the U.S. Virgin Islands, Great Pond is owned by the Government of the U.S. Virgin Islands. The land surrounding the pond is currently owned by Golden Resorts, LLLP.
Surveys by D. B. McNair, L. D. Yntema, C. Cramer-Burke and S. L. Fromer from 2002 to 2007 have confirmed 72 species of birds at Great Pond, including 39 migrants and 33 resident species. This includes 18 species of migrant shorebirds. 19 nesting species including 3 resident shorebirds have been recorded at Great Pond.
White-crowned Pigeons are listed as Near Threatened on the IUCN Red List and are on the U.S. Virgin Islands Endangered Species List. White-crowned Pigeons nested in the mangroves at Great Pond every year from 2002-2007 (DBM and LDY, pers. obs.), most commonly in the interior red mangrove manglars (McNair 2005; LDY and CCB, unpubl. data). Interior pond surveys conducted by DBM in 2003 documented 55 nesting pairs (McNair 2006). In May 2007 birds were observed from the pond’s interior, flying from nests containing eggs or young in many of the red mangrove manglars. However, most surveys since 2004 have been conducted from the perimeter of the pond. Birds calling from the tops of manglars and flying out just after dawn were counted in the months of May and June.
Least Terns are listed as Endangered in the U.S. Virgin Islands. In 2006 the northwest mudflats of Great Pond supported the third largest nesting colony (134 pairs) of Least Terns on St. Croix (Lombard 2007). In 2007, approximately 30 pairs nested on the northwest and southeast mudflats. High water levels inundated the northwestern nesting area in June 2007, destroying all 20 nests and rendering the area inappropriate for re-nesting for the remainder of the season. Some pairs in the southeastern nesting area produced fledged young in 2007. Every August from 2002 – 2007 more than 200 Least Terns have congregated at Great Pond in preparation for post-breeding migration, even though birds did not breed from 2002 - 2005.
Green-throated Caribs and Antillean Crested Hummingbirds, both restricted-range species within the Eastern Caribbean (A26), are present at Great Pond. Green-throated Carib nesting has been confirmed in the black mangroves.
Wilson’s Plovers have nested annually from 2002 to 2007 on the dry mudflats on all sides of the pond. A 2002-2003 island wide survey by DBM confirmed Great Pond, with 20% of the island’s population, as the best breeding site for Wilson’s Plover on St. Croix. V.I. Fish and Wildlife has proposed that Wilson’s Plover be listed as a Species of Special Concern in the U.S. Virgin Islands. Another resident shorebird, the Black-necked Stilt regularly nests on the silt surrounding some interior red mangrove manglars and along the western pond edge. The shallow pond edges and mudflats provide feeding and roosting grounds for hundreds of migrant shorebirds including Black-bellied and Semipalmated Plovers, Greater and Lesser Yellowlegs, Whimbrels, Ruddy Turnstone, Semipalmated, Least and Stilt Sandpipers, Short-billed Dowitchers and others
Great Blue Heron, Snowy Egret, Black-crowned Night-Heron, and Willet all occur regularly at Great Pond and are considered Species of Special Concern in the USVI. Nests of Snowy Egret, Little Blue Heron, Tricolored Heron, Cattle Egret, Green Heron and Yellow-crowned Night-Heron have been confirmed in the interior red mangroves in recent years (McNair et al., 2005; McNair and Sladen 2007; LDY and CCB, unpubl. data). Zenaida Dove, Common Ground Dove, Caribbean Eleania, Gray Kingbird, Northern Mockingbird and Black-faced Grassquit have nested in the black mangroves and/or in a variety of trees on the beach berm.
Non-bird biodiversity: Hawksbill (Eretmochelys imbricate) and green turtles (Chelonia mydas) have nested along the ocean side of the baymouth bar.
Habitat and land use
Red (Rhizophora mangle), black and white mangroves (Laguncularia racemosa) cover more than 35% of the Great Pond wetlands. Red mangrove is the primary species found throughout much of the interior portion of the pond and lines the narrow channel to the sea. Black mangrove dominates the pond fringes, except on the more open west side. White mangrove grows mainly on the southeast side and in a stand on the northeast. All three species of mangrove are protected by the Virgin Islands Endangered and Indigenous Species Act of 1990.
The mudflats are primarily bare except for patches of wetland vegetation including Sesuvium spp., saltwort (Batis maritima ) and a few small mangroves. A well head on the north side discharges a continuous stream of minimally brackish water (2 ppt), supporting a stand of Sesbania sericea and an area of wetland grass and sedge.
The baymouth bar is covered by littoral forest and scrub comprised of native vegetation such as manchineel (Hippomane mancinella), seagrape (Coccoloba uvifera), otaheiti (Thespesia populnea), bay cedar (Suriana maritima), buttonwood (Conocarpus erectus), nicker (Caesalpinia spp.) and saltwort and exotic vegetation such as tamarind (Tamarindus indica), tantan (Leucaena leucocephala) and casha (Acacia tortuosa).
Pressure/threats to key biodiversity
There are six major threats to Great Pond and its avifauna, four are anthropogenic and two due to natural events.
1. Development: Since 2003, Golden Resorts, LLLP has been working towards developing a 500 room resort with a 25,000 square-foot casino, a 1,200 seat convention center and a 294 acre golf course on the land directly adjacent to the west side of Great Pond. Construction and resort activity and noise, light pollution, multi-storied structures and increased contaminated runoff from heavy rains would have a negative impact on the bird life in the nearby pond. In spite of protective designations given to the area by the Virgin Islands and the U.S Governments (see above under Protected Areas), Golden Resorts has received tremendous support and encouragement from the V.I. Government which hopes for an economic revival. This development process has been stymied by three separate lawsuits including one brought by the V.I. Conservation Society. The chances of the Golden Gaming development coming to fruition have diminished with time and with a recent mortgage foreclosure action against the owner. Nonetheless, the site remains under threat of development. Lack of an adequate and enforceable buffer zone around Great Pond compounds its susceptibility to any nearby development.
2. Human disturbance of feeding, roosting and nesting areas: The wide bare mudflats, especially on the southeastern and northern sides of the pond, are frequently churned up by vehicles. Vehicles are driven on the mudflats to access the shore, to illegally dump waste and for recreation. 4-wheel drive vehicles are driven fast, in circles on the dried or muddy flats. All of these activities disturb the birds which feed, nest and loaf on the mudflats or in the nearby shallows.
3. Illegal dumping: Dumping of old vehicles, household appliances, tires, construction debris, household garbage and yard refuse in and around the wetlands is common. Leaching of petroleum products and other contaminants has occurred. Excessive garbage has diminished the use of some mudflat nesting areas, particularly on the southeast. Periodically these areas are cleared using heavy equipment, removing the debris but damaging the mudflats.
4. Exotic species: Mongoose and rats are numerous at Great Pond. Mongoose primarily affect birds on the dry mudflats, especially the ground nesting birds. Rat nests have been detected in the interior red mangroves. These two exotic species have negatively affected some native birds at Great Pond, but critical studies are lacking.
5. Rainfall run-off: Heavy rains can produce sheet flow of water across the mudflats. When such rainfall occurs in the spring and early summer months, Least Tern and Wilson’s Plover nests are often inundated and destroyed by the runoff or the associated pond level rise. Rainfall run-off has caused erosion in the mudflats and carries silt into the pond. Increased silt will result in a shallower pond basin, facilitating invasion by red mangroves.
6. Hurricanes: St. Croix lies in the hurricane zone that extends from the eastern Atlantic Ocean to the Americas. St. Croix was seriously impacted by four major hurricanes between 1987 and 1999. Extensive damage to tall mangroves occurs during such storms with wind speeds greater than 100 mph. This destruction initially limited bird nesting and roosting areas in the mangroves of Great Pond. Young mangroves, especially red mangrove, are less susceptible to hurricane damage and have thrived in recent years. The overall increase in red mangroves in Great Pond has resulted in more nesting area for birds such as the White-crowned Pigeon, Green Heron and other ardeiids that use these manglars.
Conservation responses/actions for key biodiversity
Island Resources Foundation, under contract with the V.I. Department of Planning & Natural Resources, performed a Comprehensive Analytic Study of Great Pond and Great Pond Bay in preparation for the site’s designation as an Area of Particular Concern (1991). The APC Analytic Study states, “The pond itself is important as a silt trap for upland runoff, a means of protection for the offshore reef and seagrass beds, a productive nursery area for juvenile fish, and an important resting and foraging ground for resident and migratory avifauna.” There is no evidence of conservation management resulting from this study or designation.
Great Pond has been included in several waterbird research studies based on multi-year wetland surveys led by V.I. Fish and Wildlife biologists. F. W. Sladen (Sladen 1992) made a comparative study of the waterbirds found at Great Pond and at Southgate Pond, St. Croix from 1981 to 1985. D. B. McNair (McNair et al., 2006) prioritized saline wetland sites on St. Croix, including Great Pond, using the abundance of six species of waterbirds observed at those sites from April 2002 to December 2004. These two sources clearly indicate that Great Pond is the most important lagoon for birds on St. Croix, USVI.
D. B. McNair (hereafter DBM) and other individuals conducted White-crowned Pigeon and Cattle Egret/Heron surveys throughout the pond in 2002 - 2007 (McNair 2006; McNair and Sladen, 2007; L. D. Yntema and C. Cramer-Burke [hereafter LDY and CCB] unpubl. data).
Great Pond was among the sites surveyed by C. D. Lombard (U.S. Fish & Wildlife) while conducting research for her Master’s thesis on the nesting ecology of Least Terns (Sterna antillarum) on St. Croix (Lombard 2007).
Monthly bird surveys have been conducted at Great Pond since 2002 by D. B. McNair (formerly of V.I. Fish & Wildlife), L. D. Yntema, C. Cramer-Burke (St. Croix Environmental Association) and S. L Fromer.
Caribbean Barrier Resource System: Great Pond is part of Unit # VI-07 of the Caribbean Barrier Resource System (CBRS) as set forth in the Federal Coastal Barrier Improvement Act of 1990. CBRS VI-07 includes all of Great Pond and extends south into the ocean past the barrier reef of Great Pond Bay.
Area of Particular Concern: In 1991 Great Pond was designated an Area of Particular Concern (APC), a Significant Natural Area and an Area of Preservation and Restoration by the Coastal Zone Management Commission, V.I. Department of Planning and Natural Resources. The boundaries of the APC include all of Great Pond and extend further to the east and west. The APC boundaries extend south from the eastern and western boundaries, out to sea to the “outer shelf ledge or the three mile limit (whichever is closer).”
St. Croix East End Marine Park: The St. Croix East End Marine Park (STXEEMP), established in 2003 by the V.I. Department of Planning and Natural Resources, encompasses approximately 60 square miles of ocean, beaches and submerged land on the eastern end of St. Croix. In the STXEEMP, Great Pond is classified as a “no-take” area, prohibiting commercial and recreational fishing.
Lisa D. Yntema, Douglas B. McNair, Claudia D. Lombard and Carol Cramer-Burke.