West Indian Iguana Habitat
West Indian xerophytic forests inhabited by iguanas have survived drastic climatic variation, geological activity, and rising and falling sea levels throughout their existence. Although they are often less tolerant of unnatural disturbance than other vegetation communities, dry forests survive hurricanes and tropical storms and recover quickly if they are in good condition. These xerophytic plant communities contain some of the world's hardest woods, harbor many spectacular bird species, and support the earth's largest saurian herbivores.
Although the Lucayan, Caloosa, Taino, and Arawak Indians probably all utilized iguanas as food, it was the arrival of Europeans that precipitated dramatic declines in iguana populations and the destruction of native habitats. In modern times, West Indian dry forests have continued to suffer steady degradation. On larger islands and in populated areas, these forests are mostly gone, although some excellent examples survive in remote or sparsely populated areas, primarily in Cuba and the Bahamas. Fragments in good condition still remain in a number of other areas, but most are under intense pressure and in danger of being lost in the near future.
West Indian dry forests have been historically referred to as thorn forests, due to the presence of cactus, agave, epiphytes, thorny or spiny trees and shrubs, and their typically low canopy. Stem densities are high, helping to reduce water loss. The substrate may be sandy, but often consists of sharp, pitted limestone containing numerous holes and crevices. Solution and sink holes in which organic soils accumulate are common, providing places for trees and shrubs to grow. Larger holes may be maintained in an open state by the annual nesting activities of iguanas.
Good quality iguana habitat on Great Sand Cay, Turks and Caicos Islands
The rough and inhospitable nature of West Indian iguana habitats, along with heat and rocky terrain, have made few people lament their destruction. In many areas, the absence of permanent fresh water has been the most important factor preventing forest degradation. On larger islands, the availability of water for irrigation has enabled agricultural development of forested areas. Limestone mining has destroyed large forest tracts on Cuba, Puerto Rico, and Jamaica. In many countries, woodcutting for charcoal, an inexpensive cooking fuel, has decimated vast areas.
Goats, burros, sheep, cattle, and other free-ranging and feral mammalian browsers contribute to destruction of iguana habitats by preventing natural regeneration of vegetation. Non-native trees such as Australian pine (Casuarina equisetifolia), non-native naturalized weeds such as jumbie bean (Leucaena leucocephala), and early successional natives such as Acacia macracantha have become dominant in many degraded xeric forests. These species have very little value for native wildlife. Lower plant diversity translates into reduced food resources for wildlife, which in turn leads to loss of more specialized organisms.
Good quality iguana habitat on Great Sand Cay, Turks and Caicos Islands.
Conservation of West Indian iguanas will be difficult in the face of growing, economically depressed human populations. Because the continued existence of dry forest vegetation communities is imperative for iguana survival, protection of habitat should be the first priority of conservation efforts. Free-ranging livestock and woodcutting for charcoal production are probably the most common negative impacts on dry forest habitats in rural areas. Because xerophytic forests are slow growing and grazing by mammalian herbivores precludes regeneration, mammals must be removed if vegetation is to recover. Reduction plans will need to involve compensation for livestock owners and may be facilitated by establishing a warden from the local community. Fences may be required to exclude browsers kept for dairy purposes from iguana areas. Elimination of woodcutting will undoubtedly require a longer time frame. Several wardens will be needed to enforce restrictions in larger areas. However, local employment opportunities could be generated by establishing plant nurseries for native species that include seed gathering and restoration planting. Reforestation with native hardwoods such as mahogany (Swietenia mahagoni) and black ironwood (Krugiodendron ferreum) in clearly defined buffer zones or close to settlements would be feasible, and plantings of a variety of indigenous species could provide firewood, medicinal plants, and wildlife habitat. Such programs could allow recovery of degraded habitats and provide strong incentives for conservation and wise management of forest resources.
