St. Lucia Photograph by WWF/ Allan Smith   Island group in the southeast Caribbean Tropical and Subtropical Dry Broadleaf Forests   200 square miles (500 square kilometers) -- about thrice the size of Washington DC Critical/Endangered

· Location and General Description
· Biodiversity Features
· Current Status
· Threats
· Ecoregion Justification
· References
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This dry forest ecoregion is sparsely distributed among the Windward Island Group of the Caribbean’s Lesser Antilles. It is commonly found as an intermediate gradient between the moister, high elevation forests and the xeric, coastal areas. Much of this ecoregion has been dramatically altered by shifting cultivation. Many areas that were once dry evergreen or semi-evergreen seasonal forest, are now cultivated and dominated by farms, rural villages, roads, pastures and banana stands. This ecoregion shares flora and fauna with adjacent moist forests and, in some areas, with species native to coastal habitats. Arid coastal areas and inaccessible interior mountains put a disproportionate amount of human-related pressures (i.e., agricultural expansion, roads, buildings, etc.) on this ecoregion. Consequently, conservation attention is of particular importance in these dry forests.

Location and General Description

This ecoregion is found in limited area on several of the Caribbean’s Windward Islands. Specifically, this includes small portions of Martinique, St. Lucia, St. Vincent, Grenada and Carriacou of the Grenadines. The ecoregion is characterized by steep topography and is most often found in the intermediate area between the rugged interior-island mountains and the flatter, xeric coastal areas.

The Windward Islands extend south from 15° 45' to 11° 45' N and from 60° 45' to 62° 00' W (Rand McNally 1988). These islands are found in the trade wind belt and lie upwind, in terms of the prevailing south-easterly wind, of the Leeward Islands. The mountainous terrain of these islands creates great micro-climatic variability within short distances therefore capture a great deal of the moisture within the air masses entering the region from the Atlantic. Hurricanes and tropical storms pass over the islands during rainy season of summer and fall. The interior highlands of these larger islands also receive rainfall in the drier winter months and additional amounts in the summer months (Walsh 1985). Annual rainfall in the interior highlands ranges from 10,000 millimeters in Dominica to 3,750 millimeters for the lower-elevation mountains in Grenada. In contrast, coastal areas receive lesser amounts ranging from 1000 millimeters on Dominica to 1600 millimeters at the southern end of St. Vincent. The dry forest ecoregion falls between these two extremes due to its moderate relief and elevation.

The Windward Islands form a volcanic island arc consisting of lava flows, ash, and pyroclastic deposits ranging from Miocene to recent in age. Some limestones are interspersed between the volcanic layers (Fairbridge 1975). Typically, lava flows outcrop on the steeper slopes and ash underlies the gentler slopes (Walsh 1985). St. Lucia, and Martinique are predominantly composed of acid andesite and dacitic rocks. Pyroclastic flow deposits, volcanoclastics, and lava domes are typical for these islands (CCA 1991). Characteristic soils in the ecoregion are clay-based and, due to the proximity to coastal areas and higher population densities, often susceptible to significant erosion (CCA 1991).

The dry forest ecoregion surrounds the central, mostly primary rain forest. It consists of an irregular band of secondary forest and dry woodland. Much of this ecoregion has been dramatically altered by shifting cultivation, leaving behind abandoned gardens that often generate groves of fern trees. Many areas that were once dry evergreen or semi-evergreen seasonal forest, are now cultivated and dominated by farms, rural villages, roads, pastures and banana stands. On St. Lucia, where much of this ecoregion is found, a large proportion of the vegetation has been altered by agricultural practices and urban developments (Faaborg & Arendt 1985). Characteristic forest plant species are generally an association of Didymopinax and Charianthus. In general the dry forests contain a high proportion of aggressive, light-loving species, younger trees and trees that more easily withstand disturbances of the soil, plus a profusion of ferns and mosses (CCA 1991).

Biodiversity Features

By virtue of its proximity to the Windward Islands Moist Ecoregion, which is very high in terms of biological richness and diversity, this ecoregion also has abundant flora and fauna. Due to its restricted size, distribution and similarity to the moist forest ecoregion however, little information exists regarding plants and animals specific only to this area.

Endemic species common to the moist ecoregion likely also use this drier ecoregion periodically and thus should be considered in descriptive literature and future conservation efforts. Notable endemics are the St. Vincent parrot (Amazona guildingii), the St. Lucia parrot (Amazona versicolor), and the Grenada Dove (Leptotila wellsi), all critically endangered. Other endemic bird species in this ecoregion are more common (Table 1.1). Eleven island-endemic reptile species occur: Anolis oculatus, A. roquet, A. luciae, A. trinitatis, A. griseus, Eleutherodactylus shrevei, E. martinicensis, E. euphronides, Typhlops tasymicris, Bothrops carribaeus and Sphaerodactylus microlepis.

Table 1.1 Endemic bird species in the Windward Islands Dry Forest Ecoregion.

Current Status

Conservation issues relevant to the greater Windward Islands are applicable to the specific dry forests of this ecoregion. Martinique, since 1953, is subject to the same legislation as metropolitan France, producing a lot of conservation involvement at the local level by French NGO’s. Yearly revisions to French legislation are produced by the Direction de la Protection de la Nature on Martinique. St. Lucia’s forestry conservation issues are directed by the Government’s Forestry Division. Forestry resources are divided into strictly protected, protected but permitting limited production on an individual tree basis, and production forests. The Wildlife Protection Act identifies wildlife that is absolutely protected, partially protected, and unprotected (Johnson 1988). Six species of mammals and reptiles and 79 species of birds are given extensive protection, while 37 birds are partially protected under legislation. The Fer de Lance viper, the mongoose, and several pest mice and rat species may be hunted or trapped year round (CCA 1991). A national park system on St. Vincent has been considered, but is not fully approved or implemented (UNEP 1996). St. Vincent’s forests are being threatened by encroaching agriculture even though all forests above 305 m are theoretically protected by legislation. Grenada has one established protected area (Grand Etang Forest Reserve), however, there is no substantive national park legislation that provides adequate authority either to establish or to manage national parks and protected areas (NPWU 1988).

Types and Severity of Threats

Justification of Ecoregion Delineation

The dry forests ecoregion of the windward Islands were designated according to Caribbean Conservation Association survey reports (1980) for each island. In order to maintain our broad scale coverage we lumped the dry woodland terrestrial life zones from all of the Leeward Island which contained this habitat type. Littoral vegetation and agricultural areas were also included, when bordering dry woodland formations. On Martinique we followed Portecop (1975), and for boundaries with mangroves we followed Lacereda (1994).

References

Caribbean Conservation Association (CCA). 1991. St. Lucia: Environmental Profile. St. Michael, Barbados.

Caribbean Conservation Association. 1980. Survey of conservation priorities in the Lesser Antilles: St. Vincent, Preliminary Data Atlas. Eastern Caribbean Natural Area Management Program, Caribbean Conservation Association, the University of Michigan and the United Nations.

Caribbean Conservation Association. 1980. Survey of conservation priorities in the Lesser Antilles: Grenada, Preliminary Data Atlas. Eastern Caribbean Natural Area Management Program, Caribbean Conservation Association, the University of Michigan and the United Nations.

Caribbean Conservation Association. 1980. Survey of conservation priorities in the Lesser Antilles: St. Vincent, Preliminary Data Atlas. Eastern Caribbean Natural Area Management Program, Caribbean Conservation Association, the University of Michigan and the United Nations.

Caribbean Conservation Association. 1980. Survey of conservation priorities in the Lesser Antilles: St. Lucia, Preliminary Data Atlas. Eastern Caribbean Natural Area Management Program, Caribbean Conservation Association, the University of Michigan and the United Nations.

Caribbean Conservation Association. 1980. Survey of conservation priorities in the Lesser Antilles: Grenadines, Preliminary Data Atlas. Eastern Caribbean Natural Area Management Program, Caribbean Conservation Association, the University of Michigan and the United Nations.

Caribbean Conservation Association. 1980. Survey of conservation priorities in the Lesser Antilles: Barbados, Preliminary Data Atlas. Eastern Caribbean Natural Area Management Program, Caribbean Conservation Association, the University of Michigan and the United Nations.

Faaborg, J. R., and W. J. Arendt. 1985. Wildlife assessments in the Caribbean. Rio Pedras, Puerto Rico: Institute of Tropical Forestry.

Fairbridge, R.W. 1975. Windward Islands. Page 667 in R.W. Fairbridge, editor, The Encyclopedia of World Regional Geology, Part 1: Western Hemisphere. Stroudburg, Dowden, Hutchinson and Ross.

Johnson, T. H. 1988. Biodiversity and conservation in the Caribbean: profiles of selected islands. Cambridge, UK.: International Council for Bird Preservation.

Lacereda, L.D. 1994. Conservation and sustainable utilization of mangrove forests in Latin America and Africa regions. Part 1, Latin America. Mangrove Ecosystems Technical Reports. Vol. 2. International Society for Mangrove Ecosystems. International Tropical Timber Organization.

National Parks and Wildlife Unit (NPWU). 1988. Plan and policy for a system of national parks and protected areas in Grenada and Carriacou. St Georges: Forestry Department, Ministry of Agriculture.

Organization of Eastern Caribbean States (OECS). 1986. Dominica, description of national legislation related to natural resources management (first stage analysis). Natural Resources Management Project. Organisation of Eastern Caribbean States, Castries, St. Lucia.

Rand McNally 1988. World atlas of nations. New York: Rand McNally.

Portecop, J. 1975. Carte ecologique de la Martinique. Map 1:75,000. Centre Universitaire Antilles, Guyane, Martinique.

United Nations Environment Programme (UNEP), Caribbean Environment Programme. 1996. CEP Technical Report. No. 36.

Walsh, R. P. D. 1985. The influence of climate, lithology, and time drainage density and relief development in the volcanic terrain of the Windward Islands. Pages 93-122 in I. Douglas, and T. Spencer, editors, Environmental change and tropical geomorphology. London: Allen and Unwin.

Woods, C. A. 1985. Endemic rodents of the West Indies: the end of a splendid isolation. Proceedings from a workshop of the IUCN/SSC Rodent Specialist Group, #4. p. 11-19.

For more general information on this ecoregion, go to the WildWorld version of this description.