|Scientific Name:||Cyclura collei|
|Species Authority:||Gray, 1845|
|Red List Category & Criteria:||Critically Endangered B1ab(iii)+2ab(iii) ver 3.1|
|Assessor/s:||Grant, T.D., Gibson, R. & Wilson, B.S.|
|Reviewer/s:||Hudson, R.D. & Hoffmann, M.|
|Contributor/s:||Lung, N.P., van Veen, R. & Robinson, O.F.|
Although suitable vegetation still exists, extensive recent surveying has not located iguanas far from the central core protected zone (<10 km²). Habitat in the Hellshire Hills continues to be degraded by human encroachment from the periphery. The Jamaican Iguana is therefore listed as Critically Endangered given its extremely small range in a single location where there is a continuing decline in habitat.
|Range Description:||According to Sloane (1725), who visited the island in 1688, iguanas were once common in Jamaica although their distribution seems to have been restricted to the drier sections of the south coast. The Jamaican Iguana declined dramatically during the second half of the 19th century, probably due to the introduction of the Indian Mongoose (Herpestes javanicus [=auropunctatus]) in 1872, changing land use patterns, and human population growth. Today, the iguana survives only in the Hellshire Hills, a rugged limestone area with suitable habitat totalling 114 km². However, extensive surveying has shown that iguanas are only found near the central core area that is protected from mongoose (<10 km²). Despite the proximity to Jamaica’s densely populated capital Kingston, the Hellshire Hills persist as a wilderness area because of its ruggedness and lack of surface water, making the area unsuitable for agriculture and large-scale settlement. The species was recorded to occur from sea level up to 200 m.|
|Range Map:||Click here to open the map viewer and explore range.|
At the beginning of the 20th century, the Jamaican Iguana was thought to have survived only on the Goat Islands, two small islets offshore from the Hellshire Hills. The iguana was believed extinct after this population disappeared in the 1940s. However, the continued survival of the Jamaican Iguana in the Hellshire Hills was confirmed in 1970 (Woodley 1980) from a single individual and again in 1990, both found by hunter’s dogs. A preliminary survey in 1990 revealed a small surviving population of fewer than 100 animals living in the least disturbed central and western sections of the Hellshire Hills. Two active nesting sites were also found though juvenile recruitment appeared to be minimal. Iguanas appear to have disappeared from northern and eastern sections of the Hellshire Hills because of extensive logging for charcoal production, use of dogs for pig hunting, and human settlements (CBSG 1993, B. Wilson and R. van Veen pers. comms. 2010).
Today, because of intensive predator control and the reintroduction of headstarted iguanas, the population in the central core area only is increasing. Field research has documented several milestones in the core area including: a greater than two-fold increase in the number of nesting females, successful reproduction among repatriated releases, and long-term survival and reproductive maturation of hatchlings (B. Wilson and R. van Veen pers. comms. 2010). The population trend for iguanas wandering outside the area protected by the mongoose trapline is unknown.
|Habitat and Ecology:||
Rugged limestone outcroppings comprise much of the Hellshire Hills with coarse red ferralic soil accumulating in crevices and depressions. Soil suitable for nesting is comparatively scarce. The vegetation of the Hellshire Hills consists of tropical dry forest, one of the world’s most threatened ecosystems. Jamaican Iguanas are found only in the remotest sections of the Hellshire Hills where the forest remains in good condition. The Jamaican Iguana feeds on leaves, fruits, and flowers of a wide variety of plant species, supplemented occasionally by animal matter, including snails and insects.
Since 1991 the known communal nest sites have been observed intensively (Vogel 1994, Wilson et al. 2004) and individuals have been marked. Nesting occurs in underground burrows, filled with loose soil, and is guarded for several days. Gravid female iguanas begin digging trial holes long before egg laying. Females deposit their eggs in mid-June, and hatchlings emerge approximately 85-87 days later. Clutch sizes range from 6-20 eggs depending on the size and age of the female. Hatching success varies from 0 to 100% and appears to be related to maternal body size and seasonal rainfall extremes (B. Wilson and R. van Veen pers. comms. 2010).
The most significant pressure on the remaining population in areas of intact forest are alien invasive predators, including mongooses, cats, stray dogs, and possibly feral pigs. Mongooses are very common throughout the Hellshire Hills and field observations indicate they prey on both young iguanas and iguana eggs. Cats occur throughout the area and are also known predators of juvenile iguanas. The dogs used to hunt feral pigs are of particular concern, as they are able to kill adult iguanas (Woodley 1980). Although feral pigs have not been observed disturbing iguana nests in the Hellshire Hills, evidence from Mona Island suggests they are potentially important egg predators (Wiewandt 1977).
Another significant problem is illegal tree cutting in the forest for use in charcoal production, a local industry that provides income to an estimated 10,000 Jamaicans. Approximately one-third of the Hellshire Hills is badly degraded as a result of this enterprise. Development projects proposing large-scale limestone mining, human settlements, and tourism also threaten the eastern half of the Hellshire Hills. Although a few localized limestone quarries might have only limited impact on the iguanas and their habitat, the new roads that would be constructed to facilitate the mining process would undoubtedly allow charcoal burners, pig hunters, and other forest users to migrate further into the forest.
The Jamaican Iguana is listed in Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), however, this iguana has not been utilized by humans since well before the late 1800s.
Although most of Jamaica’s remaining ecologically important forests, including the Hellshire Hills, are owned by the government and protected by law under the Forest Act of 1996, the Act has received little enforcement. The Hellshire Hills is currently part of the Portland Bight Protected Area (PBPA). Declared in 1999, the PBPA is Jamaica’s largest protected area and includes both of the Goat Islands. Designation as a protected area provides a promising legal instrument to prevent the expansion of large-scale development projects in the Hellshire Hills.
Following the rediscovery of the species in 1990, a local Jamaican Iguana Research and Conservation Group (JIRCG) was formed, comprising representatives from the University of the West Indies, the Natural Resources Conservation Authority, Hope Zoological Gardens, and the Institute of Jamaica. Together with a group of international iguana specialists, the JIRCG held an IUCN-sponsored workshop in Kingston in 1993, which developed a Population and Habitat Viability Assessment and a comprehensive plan for recovering this species in the wild (CBSG 1993). During the workshop, it became clear the current mortality level of juvenile iguanas in the wild was too high to permit survival of the population. This led to recommendations for a captive headstarting program at the Hope Zoo, which has resulted in the release of 138 iguanas back into the Hellshire Hills from 1996 through 2010.
The JIRCG is now known as the Jamaican Iguana Recovery Group (JIRG) and includes international collaborators. In addition to captive headstarting and release, the group continues to survey the wider Hellshire Hills, monitors individuals in the core area centered around the known nesting sites, and is detailing a complete natural history of the species (Wilson et al. 2004; Wilson and van Veen 2005, 2008). Repatriated animals have demonstrated high survivorship and are now integrated into the breeding population. Complementary predator control in the core area has resulted in improved recruitment attributable to enhanced survival among younger age classes. The group also focuses on education, international awareness, and habitat protection and improvement.
In 1994, an ex situ captive population was initiated with the importation of 12 iguanas to three U.S. institutions (Indianapolis Zoo, Fort Worth Zoo, and Gladys Porter Zoo). In 1996, this group was supplemented by a second importation of 12 iguanas to the San Diego Zoo, Central Florida Zoo, and Sedgwick County Zoo. After successful breeding in the U.S., the program has expanded to Fresno, Miami, and St. Louis zoos. The primary purpose of the U.S. captive population is to promote education, awareness, and provide support for the ongoing recovery effort of the wild population. Additionally, the captive colony is managed for long-term maintenance of genetic diversity in the event of catastrophic loss in the wild population (Grant 2010).
As a further safeguard against extinction, captive-reared juvenile iguanas may also be used to establish satellite populations on the Goat Islands, provided the islands can be rendered free of predators and goats. A priority goal, highlighted in the 2006 Jamaican Iguana Species Recovery Plan, outlines establishing a dry forest biodiversity reserve on these offshore islets and is arguably the single most critical conservation activity ensuring the long-term recovery of the Jamaican Iguana.
The species is listed on CITES Appendix I.
|Citation:||Grant, T.D., Gibson, R. & Wilson, B.S. 2010. Cyclura collei. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 24 May 2013.|
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