VI008
Southgate and Green Cay


Year of compilation: 2007

Site description
Southgate Coastal Reserve (SCR) and Green Cay National Wildlife Refuge (GCNWR) are located in the northeastern sector of St. Croix, U.S. Virgin Islands (USVI). The Caribbean Sea surrounds Green Cay NWR and separates it from Southgate Coastal Reserve. Both sites are nominated as one IBA because of their physical proximity. Southgate Coastal Reserve, established by the St. Croix Environmental Association (SEA) in 2000, consists of 41.5 ha that encompasses a 13 ha salt pond (Southgate Pond), 7.7 ha of associated wetlands, 5.8 ha of littoral deciduous woodland along a beach berm, and 15 ha of upland grassland. Two intermittent watercourses (guts) cross the property. East gut runs near the eastern boundary line and empties into the Caribbean Sea. West gut runs through the center of the property and into the salt pond basin. A man-made causeway contains Southgate Pond (hereafter SP) on the western side and a beach berm on its northern side separates it from the sea. The salinity and depth of the pond fluctuate with rainfall and associated run off from 311 ha of the upland watershed. Except when overflowing, the maximum pond depth is about 1.4 m. A dirt track traversing the property from south to north just east of the pond is used to access the beach. One derelict condominium structure is located within the delineated wetland. SEA intends to demolish the condo structure and build an interpretive center and field station at a suitable location on the upland portion of the property. Green Cay Marina, which formerly comprised part of SP, is located just west of SCR and south of Green Cay. A gated community and Tamarind Reef Hotel are adjacent to the marina. Chenay Bay Beach Resort adjoins SCR to the east. Route 83, a desalinization company, a small organic farm and pastureland border SCR on the south. Low density residential housing occurs in this area. Green Cay, an uninhabited 5.7 ha cay, lies off the north coast approximately 400 m from SCR and Green Cay Marina. Green Cay is of volcanic origin and prominent geological features include lava outcrops, tuffs, and breccias. Green Cay is saddle-shaped, with high points at the northern (12 m) and southern (21 m) ends connected by a narrow valley eight meters above sea level. The cay is mostly surrounded by steep cliffs. A small beach is found on the southern tip of the cay and narrow stretches of cobble beaches are found along the eastern and western shorelines. Green Cay was designated a National Wildlife Refuge in 1977 to protect the largest remaining population of the critically endangered St. Croix Ground Lizard (Ameiva polops), as well as to protect important bird nesting habitat. Green Cay is administered under the Caribbean Islands National Wildlife Refuge Complex.

Key biodiversity
Surveys conducted by D. B. McNair, C. Cramer-Burke, L. D. Yntema and C. D. Lombard from 2002 to 2007 have confirmed 98 species of birds at SCR and GCNWR. Of these, 24 species have nested. The Brown Pelican was listed as a federally Endangered Species in 1970 and the Caribbean population remains listed today. During 2003 and 2004 Brown Pelicans nested on the western side of Green Cay. 54 nests were documented in 2003 and 64 nests in 2004. Newly fledged young are guided by adults to SP where as many as 76 juveniles have been observed feeding. Brown Pelicans and Magnificent Frigatebirds roost year-round in the trees, cliffs, and beaches of GCNWR and in the mangroves on the north side of SP. Least Terns, listed as territorially Endangered in the USVI, breed on exposed, unvegetated mud flats at SCR when the pond bed is dry. In 2003, a large breeding colony produced 357 nests (Lombard 2007). These nests were destroyed by feral dogs. In the following years when the pond bed was not completely dry, nesting did not occur at SP until 2006 when 7 nests were documented on dry mudflats (Lombard 2007). Seven Least Tern nests were also recorded on the south beach of Green Cay in 2006. Each year in August and early September, congregations of as many as 215 Least Terns feed and loaf at SP in preparation for fall migration. Caribbean Coots are listed as Near Threatened on the IUCN Red List and as Endangered in the USVI (U.S. Virgin Islands Endangered and Indigenous Species Act of 1990). Some Caribbean and American Coots breed in mixed pairs at SCR. A maximum number of four Caribbean Coot pairs have been identified during a nesting cycle. The maximum number of active nests of both coots has been 13, when about 9 breeding individuals were Caribbean Coots. The maximum population of Caribbean Coots present at SCR since 2002 is estimated to be 34 individuals. SCR has been identified as the most important site for Caribbean and American Coots in the USVI (McNair 2006a). White-crowned Pigeons are listed as Near Threatened on the IUCN Red List and as Endangered in the USVI. Although large colonies of White-crowned Pigeons are reported to have nested on Green Cay in the early 1920’s (McNair 2006b) and cays are generally favored breeding sites for columbids on St. Croix (McNair and Lombard 2006), in recent years no more than 6 breeding pairs of White-crowned Pigeons have been observed at GCNWR. One pair of American Oystercatchers, considered Threatened in the USVI, has nested annually on the shore of GCNWR. A maximum of 8 pairs of Wilson’s Plovers have nested annually from 2002-2007 on the dry mud flats, pond bed, and beach at SCR and along the shores of GC. Wilson’s Plover is considered a Species of Special Concern in the USVI. Twenty species of migrant shorebirds have been recorded on the beaches, mud flats, and pond fringes including Black-bellied and Semipalmated Plover, Greater and Lesser Yellowlegs, Spotted Sandpiper, Whimbrel, Ruddy Turnstone, Semipalmated, Least and Stilt Sandpipers, Short-billed Dowitchers, Wilson’s Snipe, and others. The Green-throated Carib and Antillean Crested Hummingbird, both restricted-range species within the Eastern Caribbean (A26), are frequently observed at GCNWR and at SCR. The Green-throated Carib nests at SCR and the Antillean-crested Hummingbird has nested on Green Cay. The Pearly-eyed Thrasher, also a restricted range species, occurs at SCR and GCNWR. Ruddy Ducks, considered a Species of Special Concern in the USVI, nested at SCR in 2005-2007 (McNair et al., 2006; C. Cramer-Burke, unpubl. data). Before 2005, the only documented nesting of Ruddy Ducks on St. Croix was during the first half of the 20th century (McNair et al., 2006). Other species confirmed nesting at SCR and GCNWR since 2002 have included White-cheeked Pintail, Pied-billed Grebe, Little Blue Heron, Green Heron, Common Moorhen, Killdeer, Black-necked Stilt, Zenaida Dove, Common Ground-Dove, Yellow Warbler, and Bananaquit. Great Blue Heron, Tricolored Heron and Black-Crowned Night-Heron, all considered Species of Special Concern in the USVI, are frequently seen at SCR or GCNWR. In early 2006 it was documented that over 100 Cattle Egrets were roosting nocturnally at GCNWR for the first time since 2001. Large groups of Great Egret (max 76), Snowy Egret (max 140), Little Blue Heron (max 47), Black-necked Stilt (max 170), Laughing Gull (max 250), and Royal Tern (max 28) feed at Southgate Pond when water levels are low and food is concentrated.

Non-bird biodiversity: The globally endangered St. Croix Ground Lizard, listed by USFWS in 1977, was once widespread and common in coastal areas but has now been extirpated from the main island of St. Croix, likely because of the introduction of the Small Indian Mongoose. Three small populations of this endemic lizard remain on St. Croix’s cays, Green Cay, Ruth Island, and Protestant Cay. The largest population occurs on Green Cay. In 2006, 61 probable Green Turtle (Chelonia mydas) nests, 42 probable Hawksbill (Eretmochelys imbricate) nests, and 10 probable Leatherback (Dermochelys coriacae) nests were documented at SCR. Nesting activities from Hawksbill and Green Turtles have also been confirmed at Green Cay.



Pressure/threats to key biodiversity
There are five major threats to Southgate Coastal Reserve-Green Cay and its avifauna, four are anthropogenic and one is due to natural events. Invasive exotic animal species: Rats are known to have a variety of detrimental effects on native ecosystems. Rats greatly suppress natural vegetative growth by eating fresh shoots, fruits, and seeds. Rats can deter bird nesting as well as predate eggs and chicks of ground and tree nesting species. Mongoose and feral dogs primarily affect ground nesting birds; cats affect ground and tree nesting birds. Invasive exotic vegetation: Three exotic plant species, Tecoma stans, Andropogon pertusus, and Panicum maximum are becoming more abundant on Green Cay and can outcompete native species. The three exotic species do not provide suitable habitat for nesting birds or the St. Croix Ground Lizard. Human disturbance of nesting, roosting, and feeding areas: With three nearby hotels, Green Cay is a destination for tourists using hotel kayaks. Visitors often pull their boats out on the south beach and walk the island’s perimeter, which is illegal and poses a threat to foraging, roosting, and ground-nesting birds. A jet-ski / wave runner rental business opened in 2007 in the nearby town of Christiansted. Traffic from these motorcraft appears to be causing noise pollution that may disturb birds on Green Cay. At SCR, vehicles driving through wetlands and on the dry pond bed or drying mudflats have disturbed and destroyed nests of the ground nesting Least Tern and Wilson’s Plover, among others. Littering: Beach users and campers often leave garbage on the beach berm. Trash attracts mongoose which are known to predate the eggs and young of ground nesting birds and sea turtle nests. 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 vegetation occurs when wind speeds are greater than 100 mph. This destruction may limit bird nesting and roosting areas at SCR and GCNWR. The remnants of mangroves on the northern and eastern sides of SP still provide roosting areas for pelicans, herons, egrets, ducks, and rallids.

Conservation responses/actions for key biodiversity
SOUTHGATE COASTAL RESERVE: Land acquisition and resource assessment, St. Croix Environmental Association and Coast and Harbor Institute The St. Croix Environmental Association (SEA) acquired the property comprising Southgate Coastal Reserve (SCR) in 2000 and 2001. To inform decisions regarding development and management of SCR, The Coast and Harbor Institute conducted an assessment of the property and its resources. The 10 Coast & Harbor SCR Technical Reports, produced in 2004, review the geology, hydrology, ecology, history, vegetation, birds, and marine resources contained within SCR and the surrounding watershed. American and Caribbean Coot and Ruddy Duck breeding ecology, Douglas B. McNair (formerly of V.I. Department of Planning & Natural Resources, Division of Fish and Wildlife [VIDPNR, DFW]) and Carol Cramer-Burke (SEA) Research was conducted on the breeding ecology of American (Fulica americana) and Caribbean (Fulica caribbaea) Coots in 2003-2004 (McNair and Cramer-Burke 2006) and Ruddy Duck (Oxyura jamaicensis) in 2005-2006 (McNair et al., 2006). Observations are on going. Wildlife monitoring, surveys, and management activities, SEA Staff and Volunteers Daily track surveys have been conducted to monitor sea turtle nesting at the SCR beach since early 2006. Bird surveys are also conducted on a regular basis. Trapping and removal of the Small Indian Mongoose (Herpestes javanicus) is conducted in order to protect sea turtle nests and ground-nesting birds in beach areas, and on the mudflats and pond bed when dry. Human access is limited in ecologically sensitive areas and education programs are offered to youth and community groups. GREEN CAY NATIONAL WILDLIFE REFUGE: Population estimates, habitat associations, and management of Ameiva polops at Green Cay, Douglas B. McNair (formerly of VIDPNR, DFW) and Claudia D. Lombard (U.S. Fish and Wildlife Service [USFWS]) In 2002 the abundance and distribution of the St. Croix Ground Lizard (Ameiva polops) was assessed using stratified random sampling. The conservative population estimate totaled 183 individuals. Lizards were more numerous in woodland areas and the number of lizards was positively associated with shrub stems. Management recommendations included removal of invasive exotic species and woodland improvement. The restoration of habitat for the critically endangered St. Croix Ground Lizard, Claudia D. Lombard (USFWS) Over 100 native trees were planted in previously disturbed areas along the eastern shoreline of the cay in 2004. All seeds were collected from Green Cay. More trees are being propagated for future plantings. Ecology, behavior, and conservation of the St. Croix Ground Lizard, Amy Mackay and Jim Wiley (University of Maryland, Eastern Shores), Judy Pierce (VIDPNR, DFW) and Claudia D. Lombard (USFWS) The objectives of this study are to determine behavioral characteristics, habitat preferences, and size and structure of the St. Croix Ground Lizard population. Capture and translocation of the endangered endemic St. Croix Ground Lizard to Buck Island Reef National Monument, St. Croix, Lee Fitzgerald (Texas A&M), Zandy Hillis-Starr (National Park Service), Michael Evans (USFWS), and Renata Platenberg (VIDPNR, DFW) Translocation of individuals of the St. Croix Ground Lizard from Green Cay to Buck Island is being planned as a measure to mitigate the potential for catastrophic loss of remaining populations. Translocation will establish a new population on the largest cay off St. Croix and increase species range into high quality habitat in a federally protected area. Translocation will begin in 2008. The eradication of invasive rats on Green Cay, Claudia D. Lombard (USFWS) and Judy Pierce (VIDPNR, DFW) Using a live-trapping method, a total of 60 rats (Rattus rattus) were removed from Green Cay and eradication was assumed in October 2000. Regular follow-up trapping revealed no presence of rats until January 2006 when they had reinvaded the cay. In 2006, a snap-trapping rat removal program was initiated. A total of 58 rats were removed from the cay but the 2006 efforts did not achieve eradication. The vegetation of Green Cay, Roy Woodbury and Jose Vivaldi (USFWS) Vegetation surveys were conducted in 1983. A total of 60 species were identified within four ecological zones. These species include 13 trees, 20 shrubs, 9 vines and 18 herbaceous species. Several other species have been discovered subsequently. A pre-Columbian conch midden, Malcolm Weiss and William Gladfelter (V.I. Archaeological Society) An archaeological study documented that Green Cay was used by Neo-Indians for processing conch almost a millennium ago. An estimate of over 33,000 conch shells on Green Cay tells of human settlement as early as 1020 A.D

Protected areas
Southgate Coastal Reserve (SCR): St. Croix Environmental Association is planning to manage SCR as a wildlife reserve and build a Reserve Center with paths and bird blinds to facilitate environmental education and research programs. This project is currently in the permitting stage. SCR encompasses the entire onshore portion of this IBA. Green Cay National Wildlife Refuge (GCNWR): Green Cay is an uninhabited 5.7 ha cay that is closed to the public. GCNWR comprises the offshore island included in this IBA. Caribbean Barrier Resource System: Southgate Pond is part of Unit # VI-04 of the Caribbean Barrier Resource System (CBRS) as set forth in the Federal Coastal Barrier Improvement Act of 1990. CBRS VI-04 includes all of Southgate Pond and associated wetlands and extends north into the ocean. Green Cay is not included in this unit, but is classified by CBRS as an “otherwise protected area”. Area of Particular Concern: In 1991 Southgate Pond/Chenay Bay was designated an Area of Particular Concern (APC) and an Area of Preservation and Restoration (APR) by the Coastal Zone Management Commission, V.I. Department of Planning and Natural Resources. The APC boundaries extend east of SCR to Pull Point, west to Punnett Point, south to Route 82 and north to the three mile limit. 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. A no-take protected area surrounds Green Cay and the shoreline of SCR. Protected areas extend from just west of Green Cay around the east end of the island to the west end of Great Pond.

Habitat and land use
Southgate Pond (hereafter SP), just below mean sea level, is mostly devoid of emergent vegetation. When rainfall is sufficient, Ruppia maritime and Chara spp. may form extensive submerged aquatic meadows. White mangrove (Laguncularia racemosa) manglars are interspersed throughout the eastern end of the pond. The surrounding wetlands are dominated by white and black mangroves (Avicennia germinans) and a variety of herbaceous species including Sporobolis spp., crinoid grass, seaside heliotrope, seashore paspaulum, and sea purslane. Gallery forest is established along the east gut where white and black mangroves dominate and form a closed canopy. This community grades along a distinct slope into semi-deciduous woodland characterized by white manjack, seagrape and Acacia spp. The beach berm littoral woodland is composed primarily of mahogany, seagrape, genip, manchineel, and seaside mahoe with an understory of shrubs (Eugenia spp., Caesalpinia bunduc) and vines. The upland area, formerly agricultural land, is primarily guinea grass (Urochloa maxima) with scattered small trees including Acacia spp., Leucaena leucocephala, and Cordia dentate. The flora of Green Cay consists of over 60 species, most being native. Natural forest is poorly developed except for a closed mesic woodland on the southwestern part of the cay. Other less densely vegetated areas are found throughout the southern half of the cay. The dominant tree species are Cordia rickseckeri, Tabebuia heterophylla, and Hippomane mancinella. Most of the cay is covered by shrubs, mainly Eupatorium sinuatum, Oplonia spinosa, Lantana involucrate, and Clerodendrum aculeatum. The northern half of the cay is primarily a shrub-grassland association. It is characterized by impenetrable, almost monospecific shrub stands up to two meters tall, together with wind swept grasslands. Herbaceous plants are scattered throughout the cay. Three main exotic species that appear to be increasing in abundance are one tree (Tecoma stans) and two grasses (Andropogon pertusus and Panicum maximum).


Recommended citation
BirdLife International (2022) Important Bird Areas factsheet: Southgate and Green Cay. Downloaded from http://www.birdlife.org on 02/10/2022.