|Scientific Name:||Cyclura carinata|
|Species Authority:||Harlan, 1824|
Cyclura carinata subspecies bartschi Cochran, 1931
Cyclura carinata subspecies carinata Harlan, 1824
|Taxonomic Notes:||The small subpopulation on Booby Cay, The Bahamas, has been classified as a distinct subspecies, Cyclura carinata bartschi Cochran, 1931, on the basis of morphological characteristics. Genetic studies are needed to more fully evaluate whether subspecific status is warranted.|
|Red List Category & Criteria:||Critically Endangered B1ab(i,ii,iii,iv,v) ver 3.1|
|Reviewer(s):||Hudson, R. & Alberts, A. (Iguana Red List Authority)|
A comparison of 1995 survey work (Gerber 1995) combined with a less extensive survey conducted in the mid-1970’s (Iverson 1978) indicates that at least 13 iguana subpopulations, most on relatively large islands, have been extirpated over the last 20 years. This represents a 25% or greater rate of population decline. Continuing habitat loss and spread of feral mammal predators (cats, dogs and rats) are contributing to presently accelerating rates of loss. The combined area of islands supporting viable iguana populations at present is approximately 13 km². The largest remaining subpopulation (30% of total population) occurs on an island that is privately owned under extensive development.
|Range Description:||The species is found on 50–60 of the > 200 islands comprising the Turks and Caicos island banks. The combined surface area of all islands in the Turks and Caicos is approximately 500 km². The extent of occurrence for iguanas is 13 km², most of which is accounted for by three large cays (Big Ambergis, Little Ambergris and East Bay). In the Bahamas, the species is found only on Booby Cay, located 0.5 km off the eastern end of Mayaguana Island. The cay is 2 km in length and varies from 100–750 m wide. Approximately 30% of the cay is taken up by two ponds.|
Native:Bahamas; Turks and Caicos Islands
|Range Map:||Click here to open the map viewer and explore range.|
Approximately 30,000 adult iguanas remain in the Turks and Caicos islands, fragmented into 50–60 island subpopulations. Subpopulations range from islands without feral mammals, where iguanas are very common (densities may exceed 30 adults per hectare) to islands with feral mammal populations, on which iguana are either absent or extremely rare. The most important remaining subpopulations are on three large cays lacking feral predators (Big Ambergris, Little Ambergis and East Bay), the largest of which (Big Ambergris; 4.3 km²; supporting approximately 10,000 adult iguanas) is privately owned and under development.
In the Bahamas, surveys indicate that iguanas on Booby Cay were fairly numerous in 1988 and 1997, with all age classes present. However, the iguana population is restricted to a single small cay with a high point of 6.2 m and most of its area below 3 m. Although no formal census has been conducted, it is unlikely that the population exceeds 750 adults (Gerber et al., unpublished data).
|Habitat and Ecology:||The species is most abundant is rocky coppice and sandy strand vegetation habitats, and friable soil is required for nesting. It is diurnal and spends the night in burrows it has dug or in natural retreats under rocks. It is primarily herbivorous throughout its life, feeding arboreally or terrestrially on the fruits, flowers and leaves of > 60 plant species, as well as occasional invertebrates. Adult males are territorial throughout the year. Courtship and mating occur in April/May, with a single annual clutch of 2–11 eggs laid in May/June. Females defend the nest burrow for several days to weeks after nesting, but are not territorial during the rest of the year. Hatching occurs in September after about 90 days of incubation. Sexual maturity in males occurs at about 7 years and in females at 6–7 years. Annual survivorship ranges from about 55% for the first three years of life, to about 67% during years four through six, to 90–95% in adults. Life table analysis suggests that mean cohort generation time is 14 years. Preliminary data suggest that some individuals live at least 20 years.|
In the Turks and Caicos Islands, the primary threat to iguanas is introduced mammals, particularly cats and dogs. Iverson (1978, 1979) documented the near-extirpation of a population of over 5,000 adults in three years as a result of predation by feral cats and dogs. Feral livestock (goats, cows, donkeys and horses) pose a serious threat also, presumably because they compete for food plants, alter the vegetational composition of habitats and trample soft substrates where iguanas burrow and nest. In 1995, iguanas were found on only 5–26 islands with cats or livestock. Iguanas on these islands were very rare, whereas iguanas on islands without introduced mammals are common. Recently, feral cats have crossed a newly formed sand spit connecting Pine and Water Cay (two islands with cats) to Little Water Cay (an important nature reserve that was previously cat-free). Development for tourism is also an increasing cause of habitat loss.
On Booby Cay, Bahamas, the immediate threat to the population is the presence of goats, which are degrading the vegetation through over-browsing. Catastrophe, particularly in the form of a hurricane or storm surge, is a significant threat.
In the Turks and Caicos, iguanas are still occasionally eaten by local fishermen, and although illegal exportation for international trade is undocumented, it probably occurs. There have been no reports of poaching of iguanas on Booby Cay, although it is unknown is any are taken by local fishermen for consumption.
The Turks and Caicos has a fairly extensive system of national parks, nature reserves and sanctuaries, a number of which encompass areas supporting iguanas. However, these reserves are not immune to the effects of introduced mammals and few government resources are presently allocated to maintain or enforce protection of non-marine parks. Largely due to the urging of the TCI National Trust, legislation to protect iguanas within the islands has recently been drafted, although not yet implemented. In addition, the government has granted the TCI National Trust stewardship of Little Ambergris Cay, which supports a healthy iguana population, and Little Water Cay, which supports a large population of iguanas but needs management due to its popularity with tourists and recent invasion by feral cats. Finally, the TCI National Trust has initiated a public education campaign that includes a tour of all schools to discuss iguanas and other conservation issues. In November, 2003, a Conservation and Management Plan was drafted at a joint IUCN-government sponsored workshop attended by in-country conservation managers, government officials, private businessmen, and international iguana conservation experts. The plan lays out a comprehensive strategy to conserve and restore populations of the Turks and Caicos iguana within its historic range, and perpetuate it as a symbol of national pride and sound environmental management.
All Bahamian rock iguanas are protected under the Wild Animal Protection Act of 1968. The Bahamas National Trust has proposed to the Bahamas government that Booby Cay, which is also of significant value for nesting seabirds, be named a protected area under the national parks system (Carey et al. 2000). Representatives of the Wildlife Committee of the Bahamas National Trust and the Department of Agriculture are planning the removal of feral goats.
This species is listed on CITES Appendix I.
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Welch, M.E., Gerber, G.P. and Davis, S.K. 2004. Genetic structure of the Turks and Caicos rock iguana and its implications for species conservation. In: A.C. Alberts, R.L. Carter, W.K. Hayes and E.P. Martins (eds) Iguanas: Biology and Conservation pp: 58-70. University of California Press, Berkeley.
|Citation:||Gerber, G. 2004. Cyclura carinata. The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 27 November 2014.|