5.2.4. Cave Communities
Subterranean cave formation is a distinctive feature associated with karst terrain. These voids form along weak lines in the limestone rock, carved out by percolating rainwater and groundwater. At present, over 1,200 caves, passages and sinkholes have been registered for Jamaica (Fincham 1997). Per square kilometer, Jamaica has among the highest number of caves of any country in the world. Minimally, 270 caves are located within the region of the Cockpit Country and almost all are or can be used as habitats for a great variety of wildlife, including " troglobites" (found only in caves and demonstrating adaptations for life in a world of darkness [e.g., loss of pigment, partial or total reduction of eyes]), " troglophiles" (found in both cave and noncave habitats) and " trogloxenes" (caves are required for part of the species' life cycle).

Cave environments can be divided into four zones, starting at the entrance: (1) twilight zone, where light intensity, humidity and temperature vary and faunal diversity is highest; (2) transition zone, where darkness is complete but humidity and temperature vary and where many faunal species make sorties to the outside world; (3) the deep zone, where darkness is complete, temperature is constant and humidity is 100 percent and where full-adapted cave species never venture outside the cave; and (4) the stagnant zone of complete darkness, little air exchange and carbon dioxide concentrations can become lethal for non-cave adapted organisms. There is more diversity in cave entrances because of greater environmental variability and movement of organisms between the cave and epigean habitats but greater patterns of endemism in the environmentally constant dark zone. Changes to any of these zones will cause stress to cave systems (Table 9 below).

As with the Karst Freshwater Systems, maintaining energy inputs is critical to maintaining functional Cave Communities. Energy is available through localized deposits of organic material (bat guano, insect frass) and drift material washed in by streams, particularly during floods. Tree roots are also an important source of organic material. Many trees, such as figs, survive the harsh limestone surface environment by sending roots deep into the rock, often down to the water table. Specialized organisms, including fungi and mineral-fixing bacteria, use these root systems and attract arthropods, such as crickets and millipedes, which subsequently disperse small amounts of organic material throughout the cave system.

Experts judged the size of Cave Communities to be " VERY GOOD" owing to the fact that there has been little physical destruction to the caves themselves (Table 2). The condition of this target, however, was ranked as " FAIR," with all peripheral caves (i.e., caves in proximity to human settlements) having experienced degradation because of guano extraction (Table 10). Because of their isolated populations, Cave Communities, and in particular invertebrates, are highly vulnerable to localized extinctions. Connectivity between the Wet Limestone Forest and Cave Communities is critical for maintaining the ecological processes of both targets.

5.2.5. Land Snails Jamaica's Land Snails represent one of the world's best examples of adaptive radiation and speciation in terrestrial molluscs. Currently there are 555 valid species recognized on Jamaica, of which 499 (90%) are endemic to the island. Most of these species have very limited ranges and often do not occur across more than 1-4 parishes. In Cockpit Country, species diversity is as high as has been documented for Land Snails anywhere in the world: a one-hectare plot near the village of Auchtembeddie, on the southern periphery of Cockpit Country, alone hosts 87 species of Land Snails, of which 69 are endemic. Land Snails fill a broad ecological role on Jamaica, with representative detritivores, herbivores (algae, fresh plant tissue and leaves), and carnivores, as well as being prey items for other non-mollusc species.

Land Snail communities in Cockpit Country are generally still viable wherever there is good forest. Species dependent on primary forest are most threatened and large-bodied snails such as Eurycratera jamaicensis and Pleurodonte bainbridgei have suffered from extensive loss of habitat and drying of the microclimate (Tables 11 & 12). Viable populations of these species survive only in primary forest or old secondary forest. All members of the tree snail genus Anoma, which is endemic to Jamaica, are highly threatened. In the past five years of intensive surveys by malacologists from the Academy of Natural Scientists, Philadelphia, no live Anoma spp. have been found in Cockpit Country, although fresh dead shells have been found and this genus is well-represented in the sub-fossil history (faded dead shells) of Cockpit Country. The cause(s) of apparent decline of Anoma spp. is unknown.

Although individual snails have small home ranges (e.g., < 1 m2 for micro-snails), the landscape context for all snail populations was rated as "FAIR" by the experts. Conversion of closed-canopy forest to agriculture restricts the movements of most of Cockpit Country's Land Snails because of loss of food resources, shelter, and desiccation of the microhabitat.