DIVERSITY & ENDEMISM
Plant diversity and endemism are very high in the Caribbean Islands, with an estimated 13,000 species, including more than 6,500 single-island endemics. Endemism at higher levels is also exceptional, with 205 plant genera and one plant family, the Goetziaceae, found nowhere else on Earth.
Endemism is also significant at the island level; about one-quarter of the region's vascular flora is restricted to a single island – Cuba. Cuba is by far the most important island in the region in terms of biodiversity, particularly for plant diversity, with more than 6,500 vascular plants, of which about half are endemic. The largest island in the Antillean chain, Cuba accounts for about 48 percent of the land area of the entire hotspot and is home to more than half of the region's endemic plants, making it a top conservation priority for the Caribbean. Of the endemic genera in the hotspot, about 120 are confined to single islands.
Caribbean mahogany (Swietenia mahagoni, EN), a cousin of the big-leaf mahogany (Swietenia macrophylla, VU) of South and Central America, has been exploited heavily throughout the region for timber. The species has been extirpated from portions of its range, and remaining old growth stands have been plundered. Other economically valuable timber species in the Caribbean Islands include walnut (Juglans jamaicensis, VU), West Indian ebony (Brya ebenus), and poui (Tabebuia heterophylla).
There are more than 600 bird species in the Caribbean Islands, of which roughly 160 are endemic, some restricted to small areas on single islands. A remarkable 36 genera are endemic to the region, as well as two endemic families: the palmchat (Dulus dominicus) of the family Dulidae and the todies (family Todidae). BirdLife International recognizes six primary and two secondary Endemic Bird Areas (EBAs) within the Caribbean Islands hotspot, a testament to the diversity and island-specific endemism in this region. Forty-eight species endemic to the hotspot are threatened with extinction, including the Puerto Rican nightjar (Caprimulgus noctitherus, CR), Zapata rail (Cyanolimnas cerverai, EN), Zapata wren (Ferminia cerverai, EN), and Grenada dove (Leptotila wellsi, CR).
Thirteen bird species have already gone extinct; six of those species were of the genus Ara, the large and brightly-feathered macaws. The Cuban macaw (Ara tricolor), the last of the six to disappear, was hunted to extinction for food and the pet trade during the second half of the 18th century. The spectacular ivory-billed woodpecker (Campephilus principalis), which once ranged throughout Cuba and the bottomlands of the southeastern United States, has not been recorded in Cuba since 1987. However, recent reports of the species from Arkansas, although controversial, give renewed hope for its possible persistence on Cuba, and it is still listed as Critically Endangered rather than as officially Extinct.
Among the most important bird symbols for conservation in the Caribbean are the parrots, including the St. Vincent parrot (Amazona guildingii, VU), the St. Lucia parrot (Amazona versicolor, VU), and the imperial parrot (Amazona imperialis, EN) of Dominica. All three species are strikingly colored and rely on undisturbed forest for survival. Another remarkable species is the bee hummingbird (Mellisuga helenae) of Cuba. This tiny bird, which is only 5.5 centimeters long and weighs 1.95 grams, is the world's smallest bird.
The Caribbean Islands have nearly 90 mammal species, of which more than 40 are endemic. This includes two endemic rodent families: Solenodontidae and Capromyidae. The family Solenodontidae includes two surviving species, the Cuban solenodon (Solenodon cubanus, EN), and Hispaniolan solenodon (S. paradoxus, EN), which are rare giant shrews threatened by human exploitation and invasive species, including mongooses, feral cats, rats and dogs. The Capromyidae includes 20 species of rodents, known locally as hutias, which are prized for their meat and threatened by hunting, habitat loss and invasive species. The region hosts 15 endemic genera, including the fruit-eating bat genus Brachyphylla, with two species.
The West Indian manatee (Trichechus manatus, VU) is native to Cuba, Hispaniola, Puerto Rico and Jamaica. Worldwide, manatees are increasingly threatened by commercial fishing and boat-strike mortality. Another significant marine mammal species has already gone extinct. The Caribbean monk seal (Monachus tropicalis, EX), which was once widespread throughout the Caribbean, was hunted into oblivion, with the last individual collected in 1965. In total, 19 mammal species once endemic to the Caribbean are recently extinct (since 1500), including four species of Nesophontes, relatives of the solenodons.
The Caribbean Islands are particularly rich in reptiles, with over 500 reptile species, almost 470 of which (94 percent) are endemic. The diversity here includes several large evolutionary radiations of lizards, such as the anoles (Anolis; 154 species, 150 endemic) with their colorful dewlaps used in displays; dwarf geckos (Sphaerodactylus; 86 species, 82 endemic); and curly tails (Leiocephalus; 23 species, all endemic) that hold their tails in a coil as they run. This lizard fauna includes the smallest lizards in the world, Sphaerodactylus ariasae from the Dominican Republic and S. parthenopion from the U.S. Virgin Islands.
The West Indies is also home to the world's smallest snake, Leptotyphlops bilineata, which could slither through a pencil if the lead were removed. Leptotyphlops is one of a number of major radiations of snakes in this hotspot, including the large boas (Epicrates, nine species); a genus of boldly patterned snakes that change colors (Tropidophis; 26 species, all endemic); and fastmoving racers (Alsophis; 13 species, all endemic). The Aruba island rattlesnake (Crotalus unicolor, CR), endemic to Aruba, is the most threatened rattlesnake in the world. While there are fewer than 250 individuals left in the wild, the snake has been the focus of significant and successful conservation, public awareness, and research programs. A total of six snake genera are endemic to the hotspot.
Also included in the reptile fauna are nine species of rock iguana from the genus Cyclura, all threatened, including some that measure more than one meter in length. The Jamaican iguana (Cyclura collei, CR) was thought to be extinct until a small population of about 200 individuals was rediscovered in 1990 in the Hellshire Hills of Jamaica. The Cuban crocodile (Crocodylus rhombifer, CR) was once found all over Cuba and in the Cayman Islands and Bahamas, but is now found only in the Zapata swamp; and it is the most threatened species of New World crocodilians.
The Caribbean is also a center of amphibian endemism, with all of the roughly 170 native species of amphibians from four families of frogs (the Bufonidae, Dendrobatidae, Hylidae, and Leptodactylidae) endemic to the hotspot. All but a few species are endemic to single islands.
More than 80 percent of all amphibians found in the Caribbean belong to the large genus Eleutherodactylus, forest frogs that lay eggs on land and hatch into miniature adults with no tadpole stage. One Cuban species (E. iberia, CR) is the smallest tetrapod in the Northern Hemisphere, with a length of only 10 millimeters, while a golden-colored species in Puerto Rico, possibly Extinct, is one of only a few species of frogs in the world known to be live-bearing. One of the largest tree frogs (Hylidae) in the world, the Jamaican snoring frog (Osteopilus crucialis, EN), has a length of about 120 millimeters and occurs in Jamaica, where males of this declining species make a loud snoring call from within giant, hollow trees.
Among the most interesting amphibians found in this hotspot is the "mountain chicken" (Leptodactylus fallax, CR), the second largest frog in the Western hemisphere. The frog gets its name from the fact that it is a favorite culinary treat on some islands; it has been rapidly declining in numbers due to human consumption, habitat loss and disease.
The Caribbean Islands have more than 160 species of freshwater fish, about 65 of which are endemic to one or a few islands, and many of these to just a single lake or springhead. As in other island hotspots, there are two distinct groups of freshwater fishes in the Caribbean: on smaller and younger islands, most fish are species that are widespread in marine waters but also enter freshwater to some degree, while on the larger and older islands of the Greater Antilles, there are several groups that occupy inland waters, including gars, killifishes, silversides and cichlids.