Rhinoceros iguana  (Cyclura cornuta)

The main threat facing this species is habitat loss as a result of logging for hardwoods, exploitation for charcoal production and fuel wood, livestock grazing, agriculture and mining of limestone. In the Dominican Republic around 35% of suitable habitat has been totally lost; of the remaining habitat, 75% is disturbed and the situation is much worse in Haiti (2). Other threats include predation by dogs, cats, pigs, and mongooses, and illegal hunting by humans for food is a very serious problem in parts of Haiti, a country mired in poverty (2) (4). International trade in wild rhinoceros iguanas has been controlled since 1987 in the Dominican Republic, but not in Haiti (2).

Introduced exotic species pose the most serious threat to the subspecies on Mona Island, which has evolved in the near absence of predators and is therefore ill-equipped to cope with the dangers they now pose. In particular, the combined effect of pigs consuming eggs and cats preying on young has resulted in the present scarcity of juveniles on the island. Feral goats may also be having a damaging impact by gathering in sinkhole depressions on Mona's plateau where the iguana nests, and also through intense browsing pressure affecting the vegetation of the island. Although there are no permanent settlements on the island, Mona attracts many recreational pursuits, including camping, fishing, swimming, scuba diving, beach combing, exploring, and hunting. Most of these activities are concentrated along the island's sandy coastal terraces and within sinkhole depressions, areas of critical importance for iguana nesting. An additional recent concern is the emergence of an unidentified disease or parasite that causes blindness in the iguana, which in turn appears to affect the iguana’s ability to feed (2).

International trade in the rhinoceros iguana is controlled by its listing under Appendix I of the Convention on International Trade in Endangered Species (CITES). Most populations occur within protected areas in the Dominican Republic, and the species is protected under national wildlife laws. Although enforcement of these laws has improved in recent years, habitat destruction remains a problem and illegal hunting for food and for the pet trade continues. Sadly, the situation looks bleaker in Haiti, where there are no formal protected areas supporting this species and enforcement of any existing wildlife laws is unlikely. There are a large number of rhinoceros iguanas in captive breeding programmes around the world, and some have even included experimental reintroductions of captive-bred young to several protected areas in the southwest Dominican Republic. Nevertheless, the conservation of existing wild populations must remain a priority. Suggested future needs include the establishment of local educational awareness campaigns to try to reduce illegal hunting, the strengthening and enforcement of existing legislation protecting the species, and the development of a national recovery strategy. Research and monitoring programmes are also essential in order to devise and guide appropriate conservation efforts (2).

Mona Island is part of the Commonwealth of Puerto Rico, and is designated as a natural reserve by the Division of Natural Reserves and Refuges within the Puerto Rico Department of Natural Resources and the Environment (PR-DNRE). In conjunction with other organisations, the PR-DNRE has implemented some significant conservation measures, such as moving the hunting season to a time outside of the iguana’s nesting season, fencing off important habitat and remote nest sites from goats and pigs, and conducting research into the impact of feral cats and the blindness syndrome seen in several adult iguanas. Nevertheless, as the number of visitors to the island continues to grow, it is essential that they are better supervised, and that educational programmes raise awareness of the potentially damaging effects recreational activities can have to this endangered subspecies (2).