The 2002 IUCN Red List includes 2 iguanids as Extinct, 6 as Critically Endangered, 4 as Endangered, 12 as Vulnerable, 1 as Lower Risk/Near Threatened, and 17 as Data Deficient. The extinct species are both tropidurines: Leiocephalus eremitus and L. herminieri. In addition, other iguanid species that are not listed by the IUCN are declining in either number or range due to overcollecting or habitat disruption and destruction. Introduced species also may play a role in these declines. For example, numbers of horned lizards in southern California have dropped in association with the proliferation of Argentine ants, which are replacing the native ants that make up the bulk of the lizards' diet.
A number of conservation activities are under way to protect threatened iguanids. For example, the Jamaican iguana (Cyclura collei), was believed extinct until a dead lizard was found in 1970 and a second individual, this time a living male, was discovered 20 years later. Since that time, the Jamaican Iguana Research and Conservation Group formed to survey the lizard's present habitat, which is now limited to a small peninsula west of Kingston. The population, estimated at about 100 individuals, is faced with several threats in the wild, including predation of the eggs (and likely the young) by the Indian mongoose (Herpestes javanicus [=auropunctatus]). Researchers now hope to boost the population by gathering eggs from the wild and rearing the hatchlings at the Hope Zoo in Jamaica until the lizards are large enough to avoid predation. The Natural Resources Conservation Authority is also taking measures, including promoting the designation of the area as a national park, to protect the lizard's current habitat from deforestation and development. Other proposals include introducing the lizards to areas such as Great Goat Island, which supported a population of Jamaican iguanas through the middle of the twentieth century.
Another at-risk iguanid is the Turks and Caicos iguana (Cy-clura carinata carinata), which is native to these islands north of Haiti and the Dominican Republic. The lizards were once widespread, but the population is now estimated to number about 30,000 adults, and these are restricted to the smaller islands. Introduced mammals are the largest threat. Cats and dogs prey on the lizards, and now-wild livestock competes with the mainly herbivorous lizards for vegetation. Habitat destruction is also taking a toll. In an attempt to prevent the continued decline of the lizard population, the National Trust for the Turks and Caicos Islands worked with the government to draft legislation protecting the lizards from additional introduced mammals. The trust has also trapped cats in vulnerable areas. Other efforts include recently installed viewing platforms to keep tourists away from the lizards, the introduction of tourist fees to support further conservation efforts, and new educational programs to spread the word about the lizards and their plight.
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