|Scientific Name:||Cyclura cornuta (Bonnaterre, 1789)|
Cyclura cornuta ssp. cornuta (Bonnaterre, 1789)
Lacerta cornuta Bonnaterre, 1789
|Red List Category & Criteria:||Vulnerable A1acde ver 2.3|
|Range Description:||Rhinoceros iguanas are still widely distributed throughout Hispaniola, including most of its offshore islands. Their current geographic range is fragmented relative to their more continuous historical distribution, and is strongly associated with xeric regions of lower human population density. Most iguana concentrations are found along the southern side of Hispaniola, with the highest numbers in south-southwestern Dominican Republic. |
In the Dominican Republic a minimum of ten subpopulations are known. In Haiti ten or fewer increasingly threatened subpopulations may still exist.
Native:Dominican Republic; Haiti
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Rhinoceros iguanas were common and widespread until the early 1950s, but accurate information concerning current population estimates on Hispaniola is lacking. Unpublished data, based on opportunistic surveys, are available for a few localities but are inadequate for extrapolation to other areas facing different levels of disturbance, particularly in Haiti. Observations on population and habitat trends recorded since the 1970s provide a fair but rough approximation of 10,000 to less than 17,000. Iguana densities are low in the majority of the areas where they presently occur and appear to be declining. Local extirpations are known from both Dominican Republic and Haiti. Populations are seemingly stable only on Isla Beata and the extreme of the Barahona Peninsula inside Parque Nacional Jaragua.|
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||Rhinoceros iguanas are most abundant in, although not restricted to, dry forests characterized by xeric, rocky habitats of eroded limestone in coastal terraces and lowlands of the mainland and several offshore islands and small cays. In areas supporting iguanas, mean annual rainfall ranges from 470 to 1,000 mm, and mean annual temperature is 25°C. With some exceptions, the species ranges in elevation from -35 m (Isla Cabritos, Lake Enriquillo) up to 400 m. They are found in a variety of subtropical life zones and habitat types, including thorn scrub woodland, dry forest and transitional semideciduous to subtropical moist forests. |
Like other rock iguanas, rhinoceros iguanas are diurnal, spending the night in retreats. Rock crevices, caves, burrows dug in soil or sand, and hollow trunks are also used during the day for resting, cooling or sheltering. Males defend territories containing retreats attractive to females. High trees and exposed rocks are used by males for basking and overseeing defended areas. Mating takes place at the beginning of or just prior to the first rainy season of the year. Females lay from 2 to 34 eggs, with an average clutch size of 17. Females guard nests for several days after laying, and incubation lasts approximately 85 days. Females probably become sexually mature at 2-3 years of age. Rhinoceros iguanas feed on fruits, leaves and flowers of a variety of plants, depending on availability. Additional information on their ecology and natural history is summarized by Schwartz and Henderson (1991).
Continuing significant decline in quality and extent of habitat
Habitat destruction, due to extraction of hardwoods and fuelwood, charcoal production, agriculture, livestock grazing and limestone mining, represents the major threat to rhinoceros iguanas in both the Dominican Republic and Haiti. In the Dominican Republic about 13% of the human population occupy dry forest regions. These areas are also the most economically depressed and exploitation of forest habitats for charcoal and fuelwood represent important sources of income. About 75-80% of the total national demand for these products originates from dry forest habitats. In the Dominican Republic, roughly 35% of rhinoceros iguana habitat has been lost, and approximately 75% of what remains is disturbed. Both figures are much higher for Haiti.
Other important threats are predation by feral dogs, cats, mongoose and pigs on adults, juveniles and eggs, and illegal hunting of subadults and adults for food and local trade. The use of iguanas for food in Haiti is extreme in rural areas where iguanas are conspicuous enough that local people are familiar with them. International trade of wild animals from Hispaniola, a conservation problem until the mid 1980s, has been controlled in the Dominican Republic under CITES since 1987, but no such control exists in Haiti.
In the Dominican Republic, most rhinoceros iguana populations are either fully or partially protected inside existing national parks and reserves. Protected areas supporting iguana populations include Montecristi National Park, Parque Nacional del Este including Isla Saona, Parque Nacional Jaragua including Isla Beata, Las Caobas Strict Natural Reserve, El Acetillar scenic area, Sierra Martín García National Park, and Lago Enriquillo National Park, including Isla Cabritos. However, the foothill regions in the latter two areas remain only partially protected. Management in most protected areas is not intensive, and in some cases is restricted to legislation.
Compliance with international trade regulations is effective, aside from occasional smuggling of animals across the border with Haiti. Rhinoceros iguanas are protected nationally by Dominican wildlife regulations. Enforcement has improved during the past few years, but clearing of the natural habitat for development is not being prevented, and illegal hunting and poaching for food and for the local pet market continues. No formal protected areas are known within the present distribution of iguanas in Haiti. The status of protective legislation is also uncertain, although the rhinoceros iguana was included on a list of protected wildlife by the Ministry of Agriculture during the 1980s. Enforcement of any potentially existing wildlife regulations seems unlikely at present.
Rhinoceros iguanas are the most common rock iguana in captivity. A successful breeding program existed at the Parque Zoológico Nacional of the Dominican Republic (ZooDom) from 1974 to 1994, with an average of 100 young hatching annually. These efforts included experimental reintroductions of captive-bred young to several protected areas in the southwest Dominican Republic. Although a captive colony of almost 300 iguanas representing all age classes was maintained at ZooDom as of December 1994 the program has been adversely affected by administrative changes since January 1995. It is hoped that these problems can soon be resolved and the program resumed.
As of November 1995 rhinoceros iguanas elsewhere in captivity included 393,236 individuals at about 20 zoological institutions, with an additional 533 animals of unassigned subspecies, reported by seven American Zoo and Aquarium Association institutions (Christie 1995). The actual number may be higher considering holdings at some European zoos and many private collections.
|Citation:||Ottenwalder, J. 1996. Cyclura cornuta. The IUCN Red List of Threatened Species 1996: e.T6042A12363359.Downloaded on 12 December 2017.|
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