Location and General Description
Jamaica is the third largest island in the Caribbean (~11,500 km2), located at 18º 15’ N and 77º 30’ W. Jamaica emerged from the ocean in the mid-Miocene, thus it was never connected to any other landmass. Jamaica ranks fifth among the world's islands for amount of endemic plant life. In 1983, less than 67,000 ha (6%) of Jamaica was covered in undisturbed natural forest. In 1995, the World Resources Institute, ranked Jamaica as the country with the highest deforestation rate (Hoagland et al . 1995); although, these figures are considered controversial. The original lowland forests including the dry forests of this ecoregion have been almost entirely replaced by plantations and artificial savannahs (Anon 1989). A flat coastal strip of dry forest surrounds the island, which is narrow in the north. The southern coastal plains are broad, and include flat alluvial areas, and dry hills. In addition, there are small areas of mangrove and herbaceous swamp surrounding this ecoregion and at times falling with in the boundaries (Braatz 1982). The land surface is two-thirds limestone while the rest is composed of igneous rocks, sedimentary shale and alluvium deposits. Mean annual rainfall varies although it is less than 750 mm along the southern coastal part of this ecoregion (Anon 1989).
This ecoregion includes most of the northwestern, western and southern coastal areas of Jamaica. The habitats of this ecoregion all lie below 213 m in altitude and have an annual rainfall not usually exceeding 1,270 mm. The fundamental vegetation is dry, woodland, considerably modified in many areas by features of the local terrain and altered by man’s activities in the more accessible areas. There is considerable variation in species composition, with greater diversity in the less disturbed, more sheltered areas.
Jamaican endemic plant genera include Portlandia and Jacaima – an endemic monotypic genus. The sole representative of which (J. costata) is endemic to this ecoregion (Dalling et al. 1997). Of 3,003 species of flowering plants recorded from Jamaica, 830 (28%) are endemic; of 579 fern species 82 (14%) are endemic; and within the Bromeliaceae and Orchidaceae, both of which are richly represented on Jamaica, endemism is 31% (Davis et al. 1986).
More than twenty species of endemic birds, out of a total of 113 breeding species, occur on Jamaica. The total number of species present almost doubles in the winter, due to migrants from North America (Downer and Sutton 1990). Most of the endemic species of birds are spread out in forests throughout the island including this ecoregion's dry forests, contain Jamaica’s national bird, the red-billed streamertail (Trochilus polytmus) however the similar black-billed streamertail (T. scitulus) is confined to the eastern end of the island (Stattersfield 1998). These bird species require intact habitat in this dry forest ecoregion as well as in the adjoining moist forest ecoregion. The endemic Jamaican least pauraque (Siphonorhis americanus), was once found mainly in this ecoregion, but now may be extinct (Greenway 1967), although some scant evidence suggests it may still be found in very reduced numbers.
Jamaica boasts 27 endemic reptile species and 21 endemic amphibian species. Island endemic reptiles specific to this dry forest ecoregion include Eleutherodactylus cavernicola, Sphaerodactylus parkeri, Cyclura collei, Ameiva dorsalis, Celestus duquesneyi; several of these species are threatened (Dalling et al. 1997). The endangered American crocodile (Crocodylus acutus) occurs in Jamaica mainly along the south coast and is especially abundant in the Black River Morass area. The endemic, critically endangered Jamaican rock iguana (Cyclura collei) survives today only in the Hellshire Hills, a rugged limestone area of 114 km2 with fringed wetlands and beaches located 20 km west of Kingston. The Jamaican iguana declined dramatically during the beginning of the 19th century due to the introduction of the Indian mongoose (Herpestes auropunctatus) and predation by introduced dogs as well as habitat destruction. The Indian Mongoose, was first introduced to Jamaica in 1872 as well as other West Indian Islands (Hoagland et al. 1989). It is an adaptable species that has effected native vertebrates, especially reptiles and amphibians, and is responsible for the accelerated extinction of numerous endemic species worldwide (Mittermaier et al. 1999).
Several island endemic butterflies including Papilio homerus, Eurytides marcellinus and many of the more than 500 endemic species of Jamaican landsnails such as species of Pleurodonte and Annularian pulchrum are found in this ecoregion.
There are three endemic bats on Jamaica (Artibeus flavescens, Phyllonycteris aphylla, Eptesicus lynni). The sole remaining extant native mammal of Jamaica, the Jamaican hutia (Geocapromys brownii), was still considered widespread by Hoagland et al. (1989) in the dry forests of this ecoregion and moist forests although threatened by hunting and habitat loss. Its current status is unknown.
Jamaica has a protected area network more than 40 nominal areas. The majority of these are Forest Reserves, where until recently, if managed, then management focused on timber extraction and plantation forestry. Generally parks and reserves are unmanaged and unmonitored with no effective control over timber or charcoal extraction, hunting and habitat encroachment for housing or agriculture (Stattersfield et al. 1998). Funding shortages result in fragmented management and institutional responsibilities . Enforcement of laws is difficult and unproductive as in many cases the fines for violations of environmental legislation are minimal. In the 1980s the principal obstacles faced when attempting to develop a working park system included lack of public awareness, political support, protected area legislation, and a park system policy statement. At the same time the need for definition and restriction of management capacity in priority areas developed (Thorsell 1981). Some of these problems have been addressed and a few protected areas established, but some problems persist such as the lack of financial sustainability, management skills, public awareness and political support.
Types and Severity of Threats
Environmental concerns in this ecoregion are characteristic of other populated Caribbean islands. These include deforestation, soil erosion, population pressures, and lack of public awareness concerning conservation. Bauxite (aluminum ore) mining has had a major impact in the island’s forests. Among the most immediate serious threats are deforestation as a result of large and small-scale cultivation, new town and road construction and plans (as yet not approved) to expand bauxite mining in the Cockpit Country and other parts of central Jamaica. Until recently, inland forests were relatively inaccessible; however, the importation of portable sawmills as well as continued road construction into these areas has led to increased deforestation and selective cutting.
Over 1 million tourists annually put the natural resources, mainly along the coasts, under enormous pressure and in some areas tourist developments are expanding, away from the coasts into the dry forests.
Justification of Ecoregion Delineation
Our classification for the dry forests of Jamaica are based on conglomerations of the following dry forest types/formations following the vegetation chart of Brown and Heinman (1972): dry salt marsh and coastal sands, and dry woodland and confirmed using Grossman et al. (1993) classifications.
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Prepared by: Sean Armstrong
Reviewed by: In process