The Wider Caribbean region contains a rich variety of complex ecosystems with a great abundance of plant and animal species, some of them endemic to the region. Along the coast of Belize is the second longest barrier reef in the world, and the longest one in the northern hemisphere. The number of endemic species is high when compared to the total number of species. For example, in Jamaica, the ratio of endemic to total species is 27:256 for breeding birds, 20:24 for lizards, 15:19 for frogs and toads, 82:579 for ferns, and 784:3000 for flowering plants.

The Wider Caribbean region contains diverse and productive coastal and marine habitats. The region represents the greatest concentration of biodiversity in the Atlantic Ocean Basin. Because the nations in this region depend heavily on the health and the beauty of the natural world to generate income, the conservation of the region’s biological diversity is not only linked to social, cultural, and political conditions, but also to the economic realities of the region. Coral reefs, seagrass meadows and mangroves are among the best known marine and coastal ecosystems in the Wider Caribbean region and large contributors to the biodiversity of the region.

Marine biodiversity data for the Wider Caribbean region has been collected from several sources and was published in 1996 in the UNEP and World Conservation Monitoring Centre publication, WCMC Biodiversity Series No4, The Diversity of the Seas: a regional approach. Some of the data is presented here.

Caribbean Regional Sea: biodiversity data

• endemic = restricted to the region
• T = total species richness in the region
  
• % = species richness in the region as a percentage of the world species richness in each group of organism
  
• - = no data available or not applicable
  

Caribbean Regional Sea: regional endemic species

In general, seagrass diversity is fairly low, with two species endemic to the region. The diversity of seagrasses and corals is lower in the Caribbean region than it is in the Indo-Pacific, although the Caribbean has the highest number of regionally endemic genera in the world. This is due to the geographic isolation of the Caribbean Sea from other major coral areas. The region has a high diversity of molluscs and crustaceans, but a low diversity of seabirds, as is the case in many tropical regions. All species of marine turtle, except for the flatback Natator depressus breed in the region. The critically endangered Kemp’s Ridley Lepidochelys kempii is confined to the region as a nesting species. Amongst sirenians, the West Indian Manatee Trichecus manatus is almost confined to the region, although its range extends into the northern part of the Southwest Atlantic Region.