CEPF
Protecting Nature's Hotspots for people and prosperity

Biological Importance

 
Caribbean Islands

Biological Importance

The Caribbean Islands Hotspot comprises 30 nations and territories, each characterized by unique and wide-ranging biodiversity and culture. It is one of the world’s greatest centers of endemic biodiversity as a result of the region’s geography and climate: an archipelago of habitat-rich tropical and semi-tropical islands tenuously connected to surrounding continents.

Habitats and Ecosystems

Geography, climate and the large geographic expanse of the Caribbean Islands Hotspot has resulted in a diverse range of habitats and ecosystems, which in turn support high levels of species richness. Although 14 Holdridge life zones and 16 WWF ecoregions have been defined in the hotspot, there are four major terrestrial forest types, the distribution and biodiversity characteristics of which are described below.
  • Tropical / Subtropical Moist Broadleaf Forests occur mainly in lowland areas influenced by north-easterly or north-westerly winds, and on windward mountain slopes, such as the northern part of eastern Cuba, northern Jamaica, eastern Hispaniola, northern Puerto Rico and small patches in the Lesser Antilles.
  • Tropical / Subtropical Dry Broadleaf Forests are found in the Bahamas, Cayman Islands, Cuba, Hispaniola, Jamaica, the Lesser Antilles and Puerto Rico. The dry forest life zone tends to be favored for human habitation, largely because of relatively productive soils and reasonably comfortable climate. For this reason, few dry forests remain undisturbed.
  • Tropical / Subtropical Coniferous Forests (both lowlands and montane) are found in the Bahamas, Turks and Caicos, Cuba and Hispaniola where they are often threatened by timber extraction and frequent man-made fires that change their age structure and density.
  • Shrublands and Xeric Scrub occurs in areas of rain shadows created by mountains, and also in the more arid climate of the southern Caribbean (e.g. Aruba, Bonaire and Curaçao). Xeric shrublands and cactus scrub are found where suitable conditions occur throughout the Lesser Antilles and on Cuba.
The Caribbean Islands Hotspot also supports important freshwater habitats, including large lowland rivers, montane rivers and streams, lakes, wetlands and underground karst networks. In addition to providing habitat for many important, unique and migratory animals and plants, these freshwater sites provide clean water, food and many services to local communities. These services are especially important as the small islands of the insular Caribbean are surrounded by salt water, and rely greatly on limited, land-based freshwater from functional ecosystems.

With the majority of Caribbean people living close to the shoreline, coastal ecosystems, including mangroves, beaches, lagoons and cays, are essential not only for biodiversity, but for buffering coastal communities from the effects of storms, providing a basis for recreational and tourism industries, as well as nursery habitat for commercial species.

Species Diversity, Endemicity and Global Threat Status

The Caribbean Islands Hotspot supports a wealth of biodiversity within its diverse terrestrial ecosystems, with a high proportion of endemicity making the region biologically unique. It includes about 11,000 plant species, of which 72 percent are endemics. For vertebrates, high proportions of endemic species characterize the herpetofauna (100 percent of 189 amphibian species and 95 percent of 520 reptile species), likely due to their low dispersal rates, in contrast to the more mobile birds (26 percent of 564 species) and mammals (74 percent of 69 species, most of which are bats). Species endemic to the hotspot represent 2.6 percent of the world’s 300,000 plant species, and 3.5 percent of the world’s 27,298 vertebrate species.

By percentage, amphibians and mammals are the most threatened of the taxonomic groups assessed, at 77 percent and 39 percent respectively (see Table 1).

Table 1. Terrestrial Species Diversity, Endemicity and Global Threat in the Caribbean Islands Hotspot
Taxonomic
Group
Species  Hotspot
endemics 
% Endemism  Globally
Threatened 
% Threatened 
Mammals 69 51 74 27 39
Birds 564 148 26 51 9
Reptiles 520 494 95 37 7
Amphibians 189 189 100 145 77
Freshwater fish  167 65 39 5 3
Plants 11,000 7,868 72 438 4
Total 12,509 8,817 70 703 6

The high level of biological diversity in the Caribbean is due to several factors. Geologically, the hotspot has a complex history, with the Greater Antilles forming in the Pacific Oceans more than 200 million years ago, when it was attached to what is today the Yucatan Peninsula. During its eastward migration between the Americas, the Caribbean collided with other land forms along South America, creating unique landscapes and bedrock. The Lesser Antilles are the active remnants of an ancient volcanic chain, and are geologically much younger than the larger islands to the west and north. This geologic complexity provides the basis for species that find their origin along both the Pacific and Atlantic coasts of Central America. Further, several islands have particularly rugged and mountainous landscapes separated by large stretches of sea, which has resulted in the isolation of populations and eventually to speciation.

The Caribbean Islands Hotspot forms the heart of Atlantic marine diversity. Roughly 8 percent to 35 percent of species within the major marine taxa found globally are endemic to the hotspot. The shallow marine environment contains 25 coral genera (62 species scleractinian coral), 117 sponges, 633 mollusks, over 1,400 fishes, 76 sharks, 45 shrimp, 30 cetaceans and 23 seabirds. The Caribbean contains approximately 10,000 square kilometers of reef, 22,000 square kilometers of mangrove, and as much as 33,000 square kilometers of seagrass beds.

Within the hotspot, however, little variation in marine species diversity exists because of the high degree of connectivity. The strong and predictable Caribbean Current meanders through the basin year round transporting larvae between the islands. As a result, marine habitats share many of the same marine species in contrast to the region’s terrestrial biodiversity with its high rates of endemism. Large ranging and highly migratory species such as turtles, whales, sea birds and pelagic fishes inhabit different portions of the Caribbean basin during different stages of life. Despite this high degree of mixing, there are significant differences in geology, climate, productivity, and island size, all of which influence the relative abundance, extent, intactness, and vulnerability of marine biodiversity in the Caribbean.
 
 
 
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Document: The Caribbean Islands Ecosystem Profile, January 2010
English (PDF - 1.63 MB) / Français (PDF - 2.6 MB)