Ecoregions

Windward Islands moist forests

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St. Lucia. (Photograph by WWF/ Paul Butler)

The Windward Islands moist forests ecoregion are some of the most biologically rich and diverse in the Lesser Antilles, if not the entire Caribbean Basin. Steep mountains inhibit extensive human-related development while abundant annual rainfall has allowed for great floral and faunal diversity. The vegetation in Dominica’s forests, for example, comprises over one thousand species of flowering plants with about sixty woody plant and tree species per hectare (ha). The region is home to four islands in this ecoregion suffer from similar human-related pressures, i.e., agricultural encroachment, hunting, and limited enforcement of wildlife and environmental legislation. Increased communication, networking, and effort of conservation on a regional basis are needed to ensure that these rich forests and their wildlife are maintained and protected.

Location and General Description 

This ecoregion is found in much of the central portion of each of the Caribbean’s Windward Islands and is characterized by rugged mountains, lush tropical vegetation and high annual rainfall. Specifically, this includes 70 to 95% of each of the following islands: Dominica, Martinique, St. Lucia, St. Vincent, and Grenada.

caption WWF The Windward Islands extend south from 15° 45' to 11° 45' N and from 60° 45' to 62° 00' W. These islands lie within the trade wind belt and lie upwind, in terms of the prevailing south-easterly wind, of the Leeward Islands. The rugged topography of these islands contributes strongly to micro-climatic variability within short distances and serves to capture a great deal of the moisture contained within the air masses that enter the region from the Atlantic. The rainy season occurs in summer and fall. Hurricanes and tropical storms pass over the islands during this period. The interior highlands of these larger islands also receive rainfall in the drier winter months and additional amounts in the summer months. Annual rainfall in the interior highlands ranges from 10,000 millimeters (mm) in Dominica to 3750 mm for the lower-elevation mountains in Grenada.

The Windward Islands form a volcanic island arc. Lava flows, ash, and pyroclastic deposits ranging from Miocene to recent in age are the principal bedrock found in these islands. Some limestones are interspersed between the volcanic layers. In general, Grenada and St. Vincent are composed of basalts and basaltic andesites. Typically, lava flows outcrop on the steeper slopes and ash underlies the gentler slopes. St. Lucia, Martinique, and Dominica are predominantly composed of acid andesite and dacitic rocks. Pyroclastic flow deposits, volcanoclastics, and lava domes are typical for these islands. Characteristic soils in the ecoregion are clay-based and, where undisturbed, minimally eroded.

Much of the mature moist forest in this ecoregion is an association of Dacryodes excelsa, Sloanea spp. and Amanoa caribaea. Undercanopy species include Licania ternatensis and Tapura antilliana and numerous epiphytes and lianas. Secondary rain forests, i.e., areas previously occupied by mature rain forest that have experienced disturbance, primarily logging and shifting agriculture, are characterized by Miconia mirabilis, Cecropia schreberiana, and Smaruba amara. The steep slopes of this ecoregion, once denuded of their cover by clearing and exposed to the erosive force of rain, are particularly vulnerable to accelerated erosion and recurrent landslides. Cultivated crops that exacerbate this problem include Sacharus officinarum, Musa spp., Theobroma cacao, Persea americana, Artocarpus altilis, Colocasia spp., Psidium guajava, Mangifera indica, Carica papaya, Ananas comusus, and Citrus spp.

Biodiversity Features

caption St. Lucia parrot. (Photograph by Phillip Coffey / Wildlife Preservation Trust)

Few areas of comparable size anywhere in the world are endowed with a botanical heritage as diverse and interesting as the flora in this ecoregion. The five main Windward Islands boast nearly 168 regionally-endemic tree species. Dominica’s undisturbed forests, for example, have been identified as the most extensive in the Lesser Antilles. The vegetation comprises over one thousand species of flowering plants with about sixty woody plant and tree species per hectare. The forest structure of this ecoregion is typical of tropical rain forests, i.e., species richness is very high and floral endemism is common. Typically, three tree strata are found and the highest, at 30 meters (m), comprises a dense canopy in which Dacryodes excelsa is dominant. Epiphytic ferns, aroids, and bromeliads coat the branches of trees. The two lower tree layers are discontinuous and each has its own distinctive species composition. In areas where the rain forest is degraded, groves of palms or tree ferns may be common.

Table 1.1. Endemic bird species in the Windward Islands Moist Forest Ecoregion.
Common Name Species Location
St. Vincent Parrot Amazona guildingii St. Vincent
St. Lucia Parrot Amazona versicolor St. Lucia
Imperial Parrot Amazona imperialis Dominica
Red-necked Parrot Amazona arausiaca Dominica
Whitsling Warbler Catharopeza bishopi St. Vincent
House Wren Troglodytes aedon St. Vincent
St. Vincent Solitaire Myadestes genibaris St. Vincent
St. Lucia Black Finch Melanospiza richardsoni St. Lucia
Semper’s Warbler Leucopeza semperi St. Lucia
St. Lucia Oriole Icterus laudabilis St. Lucia
Martinique Oriole Icterus bonana Martinque
Blue-headed hummingbird Cyanophaia bicolor Dominica + Martinique
White-breasted Thrasher Ramphocinclus brachyurus Martinique + St. Lucia

This ecoregion is similarly high in faunal richness and diversity. Dominica supports over 50 species of resident birds, including two endemic parrots (imperial parrot, Amazona imperialis; red-necked parrot, Amazona arausiaca), both that are endangered. Based on field-work between 1982 and 1987, Evans estimated that the total population for these endangered species reached levels as low as about 60 imperials and 200 red-necks. Other parrots endemic to this ecoregion are the St. Vincent parrot (Amazona guildingii) and the St. Lucia parrot (Amazona versicolor), both also critically endangered. Numerous other island and regional endemic bird species occur in this ecoregion (Table 1.1.).

All Antillean amphibians (Table 1.2) are frogs, and two Lesser Antillean endemics, a small tree frog, Eleutherodactylus martinicensis, and the large "mountain chicken" Leptodactylus fallax, occur principally on Dominica. The reptile fauna in this ecoregion is more diverse as is indicated by the number of endemics. Eleven island-endemic species occur. Of these, five are anoles (Anolis oculatus, A. roquet, A. luciae, A. trinitatis, A. griseus), three are eleuths (Eleutherodactylus shrevei, E. martinicensis, E. euphronides), two are snakes (Typhlops tasymicris)(Bothrops carribaeus) and one is a gecko (Sphaerodactylus microlepis).

There are no island-endemic mammals in this ecoregion. All extant mammal species were introduced by Amerindian or Colonial settlers. Commonly introduced mammals in this ecoregion are the mongoose (Herpestes officinarum), agouti (Dasyprocta antillensis), opposum (Didelphis marsupialis), pig (Sus scrofa), and domestic cat and dog. Grenada is home to the introduced Mona monkey (Cercopithecus mona) who is now often persecuted because of conflicts over agricultural crops. The only known endemic mammal from this ecoregion (Giant West Indian rice rat, Megalomys desmarestii) is presumed extinct. Bats are common to this ecoregion with as many as 12 species occurring in Dominica though none is an island or ecoregion endemic. There are no remaining endemic rodents in the Lesser Antilles.

Current Status

Table 1.2. Endemic amphibian and reptile species in the Windward Moist Forest Ecoregion.
Common Name Species Location
Dominica Anole Anolis oculatus  
Martinique Anole Anolis roquet  
St. Lucia Anole Anolis luciae  
St. Vincent Bush Anole Anolis trinitatis  
St. Vincent Tree Anole Anolis griseus  
St. Lucia Pygmy Gecko Sphaerodactylus microlepis  
St. Vincent Eleuth Eleutherodactylus shrevei  
Grenada Eleuth Eleutherodactylus euphronides  
Martinique Eleuth Eleutherodactylus martinicensis  
Grenada Blindsnake Typhlops tasymicris  
Fer De Lance Bothrops caribbaeus St. Vincent
Mountain Chicken Leptodactylus fallax Regional endemic

The biologically rich forests of this ecoregion have drawn much conservation attention and consequently several important protected areas exist. Notable examples are Morne Trois Pitons National Park (6,840 ha) and the Northern Forest Reserve (22,000 ha) in Dominica, the Grand Etang Forest Reserve (1,544 ha) in Grenada, Caravelle Nature Reserve (517 ha) and the Martinique Regional Park (70,150 ha) in Martinique, and the St. Lucia Nature Reserve (1,600 ha), the Dennery Forest Reserve (148 ha), the Quilles Forest Reserve (854 ha), the Ve-Vottier Forest Reserve (200 ha), and the St. Lucia Parrot Reserve (1,500 ha) in St. Lucia.

Dominica still has large undisturbed montane forests that are regionally significant but inadequately protected. The Minister of Agriculture is able to set up protected areas under the authorization of the National Parks and Protected Areas Act and terrestrial wildlife is protected under the Forestry and Wildlife Act. Martinique has some of the Caribbean’s largest forest tracts though much is secondary. Martinique has been subject to the same legislation as metropolitan France since 1953, producing a lot of conservation involvement at the local level by French NGO’s. 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. A national park system on St. Vincent has been considered, but is not fully approved or implemented. St. Vincent’s forests are being threatened by encroaching agriculture even though all forests above 305 m are theoretically protected by legislation. Although Grenada has one established protected area (Grand Etang Forest Reserve), there is no substantive national park legislation that provides adequate authority either to establish or to manage national parks and protected areas.

Types and Severity of Threats

Except for remote, inaccessible areas characterized by high relief, much of the forest on different islands in the Windward Islands Moist Forest ecoregion suffer from similar human-related pressures, i.e., agricultural encroachment, hunting, and limited enforcement of wildlife and environmental legislation. An improved infrastructure of roads on most of the Windward Islands has allowed greater access to previously undisturbed forests and accelerated conversion of primary forest to agricultural plantations. Perhaps the most fundamental problem facing the managers of Dominica's forests is the rapidly expanding pressure on the forest resources as a source of timber, fuelwood and charcoal, and as areas increasingly utilized for crop cultivation. Regionally, two aspects of current forestry legislation are considered weak, penalties for forest offenses are too low for deterrence, and there is no mechanism for ongoing co-ordination of decision-making between forestry and other sectors concerning land-use planning and development control.

Justification of Ecoregion Delineation

The moist forests of the Windward Islands were classified by conglomerating the following moist terrestrial life zones for each individual island, designated by the CCA Preliminary Data Atlas listed below: moist forest, rain forest, and cloud forest. Small islands with minimal moist forest coverage were lumped with the dominant vegetation cover to maintain the broad scale classification scheme.

Additional Information on this Ecoregion

Further Reading

  • 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.
  • Carrington, S. 1998. Wild plants of the eastern Caribbean. London: Macmillan Education LTD. ISBN: 033367443X
  • Evans, P. 1988. The conservation status of the Imperial and Rednecked Parrots on the island of Dominica, West Indies. ICBP Study Report No. 27, Cambridge UK.
  • Honacki, J. H., K. E. Kinman, and J. W. Koeppl. 1982. Mammal species of the world. Lawrence, Kansas: Allan Press, Inc. and The Association of Systematics Collection. ISBN: 0942924002
  • International Council for Bird Preservation (ICBP). 1990. The development of Morne Diablotin National Park and Nature Center in the Commonwealth of Dominica, 1990-1993. Final draft of project proposal. Cambridge, UK.
  • Johnson, T. H. 1988. Biodiversity and conservation in the Caribbean: profiles of selected islands. International Council for Bird Preservation, Monograph No. 1., Cambridge UK. ISBN: 0946888140
  • 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. Forestry Department, Ministry of Agriculture, St Georges. 130 pp.
  • Organization of Eastern Caribbean States (OECS). 1986. Dominica, description of national legislation related to natural resources management (first stage analysis). Natural Resources Management Project. Organization of Eastern Caribbean States, Castries, St Lucia. 15 pp.
  • Portecop, J. 1975. Carte ecologique de la Martinique. Map 1:75,000. Centre Universitaire Antilles, Guyane, Martinique
  • Rand McNally 1988. World atlas of nations. New York: Rand McNally. ISBN: 0528833154
  • Stoffers, A. L. 1993. Dry coastal ecosystems of the West Indies. In E. van der Maarel, editors, Ecosystems of the world 2B: dry coastal ecosystems Africa, America, Asia and Oceania. B.V.: Amsterdam Elsevier Science Publishers.
  • 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. ISBN: 0045510741
  • Wright, R.M. 1985. Morne Trois Pitons: Case study in park establishment in the developing world. Unpublished report.
  • 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.

 

 

Disclaimer: This article contains information that was originally published by the World Wildlife Fund. Topic editors and authors for the Encyclopedia of Earth have edited its content and added new information. The use of information from the World Wildlife Fund should not be construed as support for or endorsement by that organization for any new information added by EoE personnel, or for any editing of the original content.

 

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Citation

Fund, W. (2014). Windward Islands moist forests. Retrieved from http://www.eoearth.org/view/article/157143

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