Dolphin Head and adjacent forested mountains (hereafter referred collectively as Dolphin Head) are located at the western end of Jamaica. The area is recognized as the western-most portion of the mountainous spine stretching across Jamaica from the John Crow Mountains (limestone) and Blue Mountains (igneous shales) in the East through Mount Diablo and Cockpit Country (limestone) and igneous Central Inlier of the Central Plateau, to the limestone-over-shale Dolphin Head mountains of the Hanover Block in the West. Considered part of the Western Uplands: “Although partly isolated from each other, these upland areas all lie on the western side (Hanover Block) of north-south trending fault zone (Montpelier-Newmarket Graben). Although the southern areas (801 m) are higher in elevation, Dolphin Head (545 m) has the better-developed wet limestone forest.” (Hedges,1999).
The forests of Dolphin Head have been broadly classified as evergreen seasonal and closed broadleaf forest (Beard, 1955; Forestry Department, 2001). Dolphin Head includes a core area consisting of two Forest Reserves (Raglan Mtn. and Bath Mtn.), Crown Lands managed by the Forestry Department (FD), and privately-owned lands of natural, closed- and disturbed broadleaf forests and forestry plantations. Surrounding this core is a mosaic of mixed- and non-forest land use, including bamboo, sugarcane, pasture, small family farms of yam, banana, and fruit trees, and rural communities. The remnant forest has been depleted for more than 300 years by the harvesting of valuable timber species and for fuelwood associated with sugarcane and slaked lime production. Illegal timber harvesting and clearing of hilltops for marijuana (Cannabis sativa) cultivation occurs within the Forest Reserves and on private lands.
Although no species of bird is restricted in range to Dolphin Head, 21 of Jamaica’s 28 endemic land birds, 23 of 70 resident breeding birds and 11 migratory species occur across the gradient of available habitats. Forest-dependent birds include the endemic Ring-tailed Pigeon, Jamaican Elaenia, and the Arrow-headed Warbler.
Of additional ornithological interest is the presence of species that make pronounced altitudinal migrations, nesting in mid- and upper elevation forest and extending their ranges into the lowlands and secondary-growth habitats during winter months (outside the breeding season). This pattern is pronounced in the Rufous-throated Solitaire (Myadestes genibarbis), which is endemic to the insular Caribbean.
Non-bird biodiversity: Dolphin Head supports the highest density of endemic plant species and rare or threatened species per unit area for Jamaica.
Nearly 150 species, representing 61 families in 10 classes of 4 phyla, have been reported historically or were observed in the 2001 study in the Dolphin Head Area. At least 50 of these species are endemic to Jamaica and a minimum four (1 Sesarma freshwater crab, 2 Lampyridae fireflies, 1 species of Operculate snail) are endemic to Dolphin Head. Identification of several unknown species of earthworms (Class Oligochaeta), cricket (Order Grylloptera), and grasshopper (Order Orthoptera) may increase the number of localized endemic species. Fourteen butterfly species were observed, the majority during the summer survey period. This increases known species richness from two (Brown and Heineman, 1972) to 16 for the Dolphin Head area. Only one species, Calisto zangis, is endemic to Jamaica; all other species are widespread and common throughout the Americas. The species endemic to Dolphin Head are relatively small animals with limited dispersal capabilities and predicted small home ranges. To contrast, there were no birds or bats whose ranges were restricted to this relatively small area. However, 21 of Jamaica’s 28 endemic landbirds and one of four endemic bats were identified, thus contributing to the recognition of Dolphin Head as important habitat both nationally and globally.
Three species of reptiles were unique to one of three quadrats, including the Jamaican Black Groundsnake (Arrhyton funereum), which represents the first known sight-record for this small colubrid snake in Dolphin Head (see Schwartz and Henderson, 1991). The most species-rich site for reptiles, which included the location of the Black Groundsnake, was the same saddle corridor located along the trail leading to Dolphin Head Monument where invertebrate species richness was highest.
Perhaps the most important new discovery of the field surveys with regards to wildlife was the identification of a large bat roosting and nursery chamber in King’s Pen, Westmoreland (Line 9, Plot 49; 18021’01”N, 78009’14”W). This cave had been known by several local persons for more than 50 years, but it was not documented in the Jamaica Cave Registry. At least two species were resident in the cave, the Moustached Bat (Pteronotus quadridens) and the Leaf-chinned Bat (Mormoops blainvillii). The current IUCN Red List of Threatened Species (IUCN, 2000) lists Mormoops blainvillii and Pteronotus quadridens as "Near-Threatened," meaning they are not conservation dependent but are close to being considered "Vulnerable". Both of these species are endemic to the Greater Antilles. This cave represents the largest colony of roosting and breeding bats in the Dolphin Head environs identified thus far. Because of their biomass, the bats probably represent the most important consumers of insects in Dolphin Head.
In contrast to the King Pen cave, the next largest identified bat colony was found in Clifton Cave. Two species were present, the insectivorous Parnell’s Moustached Bat (Pteronotus parnellii) and the frugivorous Jamaican Fruit Bat (Artibeus jamaicensis). Their populations were estimated to be fewer than 500 individuals. The Jamaican Fig-eating Bat is one of four bats endemic to Jamaica and is the sole species in the genus Ariteus (i.e. the genus is endemic to Jamaica). It is not believed to be a cave-dwelling bat, but most likely roosts and breeds in tree hollows. It is rare in collections and as early as 1942 was thought likely to become scarce because of intensive agricultural development. The Jamaican Fig-eating Bat is listed as “Vulnerable” by the IUCN. Almost nothing is known of its ecology and habitat requirements.
Habitat and land use
These figures for Dolphin Head proper – From Forestry Dept Report). Modified/disturbed mesic limestone forest:Hill tops (48%) and Lower slope/valley (44%).
Landuse: Watershed (primary), Wildlife Conservation & Research, Agriculture/Pasture and Recreation/Tourism (secondary).
Pressure/threats to key biodiversity
The forests, caves and surrounding human-modified habitats of Dolphin Head support diverse faunal communities, which include a minimum of 50 species endemic to Jamaica and four endemic to Dolphin Head. These species differ in their use of habitats, both spatially and temporally. While some species benefit from human modifications to the forest and landscape structure, others demonstrate greater sensitivity to degradation, fragmentation, and loss of natural forest cover. As a general trend, the endemic species were restricted to areas of closed-canopy or moderately disturbed forest, while introduced species were restricted to converted habitats. However, two harmful species, the mongoose and marine toad, have penetrated the closed-canopy forest. The results of this research reveal the importance of distinguishing not only the type of human modification but also the location of the disturbance in relation to forest cover in seeking to understand how habitat change affects different taxonomic groups of wildlife.
For birds, clearing of hilltops had a negative effect on species composition and abundance. This site location is preferred for marijuana cultivation because of the direct sunlight and pockets of soil, in contrast to hillsides with little soil formation or low-lying areas with soil but where sunlight is restricted. Of the four hilltops that were assessed for avian diversity, one was under cultivation while the other three had been abandoned for at least 10 years (Anonymous, pers. comm.). The abandoned hilltops were dominated by non-native fern and lantana. These patches showed low usage by both endemic and migratory birds. With the exception of aerial hunters that perched on fire-burned snags, use of this habitat by other birds was restricted almost exclusively to the well-defined forest edge. Natural forest regeneration of these hilltops may be limited in the absence of human mitigation, particularly if the present vegetation either fails to attract seed-dispersing wildlife or competitively excludes native plant species.
Avian diversity increased in valleys with disturbed broadleaf forest or when the forest canopy was kept open because of a road (that is, a gap was created, but unlike on hilltops, the gap was bounded by forest). This type of disturbance may even be seen as beneficial to bird diversity because of the regeneration of early succession herbaceous ground cover and understory, which supported the granivores and small frugivores, and by the maintenance of open gaps which are preferred by the larger species or aerial (flycatching) insectivores. The adjacent closed-canopy hill slopes supported the smaller aerial insectivores, many of which are endemic to Jamaica, and the larger frugivorous Columbids, which were restricted in their use to closed and minimally-open canopy.
Thus, conversion of forest affects taxonomic communities differently. Clearing for marijuana cultivation on hilltops has the greatest effect on avian diversity but apparently minimal effect on terrestrial invertebrates, which have low levels of natural occurrence on hilltops. Clearing in saddle-corridors or valleys, in contrast, will have an important negative effect on terrestrial invertebrates while being neutral or even positive for birds. In all instances of forest clearing, however, there is the risk of species extinctions, particularly for plants or other highly-localized fauna. Additionally, the opening of the forest canopy facilitates the spread of many non-native species, including the Marine Toad and the Lesser Antillean Eleuth.
Conservation responses/actions for key biodiversity
Efforts towards conservation and public education are being undertaken by the Dolphin Head Trust (http://www.dolphinhead.org/) and Jamaica’s Forestry Department’s paper “ANALYSIS OF FOREST ENVIRONMENT RELATIONSHIPS, DOLPHIN HEAD, JAMAICA. Prepared by Roland Camirand
Trees for Tomorrow Project Draft report, November 2002” indicates their acknowledgement of the value of the area. Further, one of the relatives of a large land-owner (Christopher Samuels) is being trained by Windsor Research Centre, and is already an accomplished bird bander.
Dolphin Head is a proposed National Park. The protection and conservation of this limestone ecosystem is recognized nationally and globally for its unique biological diversity. The area nominated as an IBA (7301 ha) encloses 3 Forest Reserves: Raglan Mountain (101 ha), Bath Mountain (121 ha) & Burnt Savanna (ca. 80 ha). Raglan Mountain and Burnt Savanna reserves are located in watershed #25; Bath Mountain straddles the boundary of watersheds # 25 and #2.