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Site description (2007 baseline):
Site location and context
The Ashton wetland, the largest in SVG, is part of Ashton Harbour on Union Island. It is located at the island’s south (Figure 12). Associated with these mangroves (Plate 3) were seagrass beds rich in lobster and conch, coral reefs comprised of fringing, patch, and barrier reef types, and an offshore island (Frigate) that was an important bird habitat (Price and Price, 1994a). The Ashton Harbour is a Conservation Area under The Fisheries Act of 1986.
Despite official designation as a PA, and an environmental impact assessment that showed development would be devastating for reefs, seagrass beds and fishery, a 300-boat marina project began at the lagoon (Price and Price, 1994b), and experienced the anticipated results. The site now lies abandoned (Plate 4).
In terms of vegetation, four species of mangroves (
Avicennia germinans, Rhizophora mangle, Languncularia racemosa and Conocarpus erectus) can be found in this 61.78-acre (25-hectare) (Ivor Jackson and Associates, 2004) stand, although
A. germinans (48 /19.43 ha) and
R. mangle (2 /0.81 ha) dominate (Simmons and Associates, Inc., 2000).
Rainfall on the island is greatest during the months July to November, with a 26-year average ranging between 4 and 6 inches (106.0 and 148.2 mm) (Daudin, 2000). During the drier months, December to May, this annual average falls to between 1 and 3 inches (26.2 and 83.4 mm) (Daudin, 2000). Droughts are a regular phenomenon that is worsened by poor distribution of rainfall. Thus potable water is purchased and also obtained by collecting and storing rainwater. Hurricanes, though not very regular, can have devastating effects. In 1955, hurricane Janet caused significant damage on the island, which took almost five years to recover thereafter (Daudin, 2000).
Data on bird counts or populations do not currently exist. It is unlikely that any has been conducted in recent years. The presence of the Piping Plover, Caribbean Coot and Eskimo Curlew have not been confirmed, due to the paucity of data and related studies. Other waterbird species including willets, whimbrels, turnstones and sandpipers have been observed at the site.
Several Congregatory species including the Laughing Gull, Magnificent Frigatebird and Brown Pelican also forage, roost and possibly nest on the site.
Non-bird biodiversity: Though abundance and distribution are unknown, a population of the regionally endemic Congo snake M. bruesi occurs on the island. Some variation exists between the colouration of Congo snakes on the mainland and in the Grenadines, with the latter tending towards a redder hue. The recently discovered (2005) endemic gecko Gonatodes daudini occurs on this island. Its range thus far appears to be restricted to Union Island.
Pressure/threats to key biodiversity
There are a number of threats to the flora and fauna of Union Island. These include severe droughts that reduce water levels in wetlands and other watering holes and may cause death of land and water birds. Droughts also directly affect the availability of food and habitat for birds and other wildlife, and are further augmented by the ‘let-go season’ - the practice of releasing ruminants, particularly cows and goats, to allow them to feed freely during periods of food scarcity. Ruminants strip the land of vegetation leaving only the least palatable plants; and thus damaging bird habitats and increasing the erosion rates on exposed soils.
Union Island is the hub of tourism activities in the southern Grenadines and the gateway to the Tobago Cays, which are internationally renowned for yachting and scuba diving. Large cruise ships also sail through these waters causing disturbance to marine birds.
Wetlands are threatened with development and harvesting of vegetation for fuelwood. Finally, the Ashton Lagoon is affected by pollution from run-off from land, particularly after heavy rains, and from the inconsiderate dumping of garbage by persons who take monies from yachts under the false pretense that they would dispose of the garbage at the landfill.
Recommended citation
BirdLife International (2024) Important Bird Area factsheet: Ashton Wetland (St Vincent and the Grenadines). Downloaded from
https://datazone.birdlife.org/site/factsheet/ashton-wetland-iba-st-vincent-and-the-grenadines on 23/12/2024.
