C ARIUBEAN SEA .... Q) 8 60 120 A EcOSYSTEM ASSESSMENT Ul Q) :a ::J 0 80 u; 40 0 .... Q) $ ::J 20 0 40 E 0 () '#- .0 ::J z Ul .0 <( 000000 0 0 1977 1982 1987 1992 1997 0 2002 FIG. 2.4. Absolute per cent coral cover from 1977 to 200 I across the Caribbean SouRcE: Gardener et al. 2003. which are still present. These include hurricane damage; disease; bleaching; 15 pollution, including sediment runofl' from coastal developments and agriculture; ovcrlishing; and direct damage from boat anchors, lish traps, grounded ships, dredging, collection, and dynamite. All of these impacts probably have some human component. Global wanning may have led to more frequent occurrence of severe hmTicanes which results in mechanical damage to reefs and is also largely responsible for coral bleaching. The spread of coral diseases has probably been enabled by shipping and possibly through increased transport of disease organisms over long distance via dust through descrti lication."' Overlishing, especially of alga-grazing !ish such as parrot !ish, has allowed algae to overgrow corals. Jamaica, for example, has been cited as having some of the most ovcrlished coral communities in the world." Pollution, principally elevated nutrient levels fi·om sewage and agricultural fertilizers, has further stimulated the growth of these algae. In !act, most Caribbean reels have experienced a shift in ecological dominance from corals to algae. Recovery has been both rare and, when present. slow. 2. 7.4 Mtmgrol'es A mangrove is a tree or shrub adapted to colonize tropical, sheltered, coastal environments between the high-water and low-water marks. Mangroves reach their greatest development in estuaries, where they may lbnn l-IThe trend line represents the dcclim! in live com! cover hust.:d on weighted means of I studies. the exact number of which arc shown hy open circles. The error bars indicate 95%, confidcnc\! intervals. 15Coral bleaching is u phenomenon in which clcvut,:d sea tcmpcnnurcs cause stress to the symbiotic ulguc1 which then leave the tissues of the coral polyp. Since algae provide pigment to the comls, tht! reef loses its colour and rapidly declines in biodiversity. C;:trihbcun comls typically bleach when the \V;..IIcr tcmpcmturc exceeds 30"C. 16Scc Section 3.3. 17Scc Scc1ion 3.2. 15 extensive lbrcsts. The term mangrove is also used to describe the complex community of animals, plants, and micro-organisms adapted to life in a saline and muddy environment. Tree-dwelling animals, including nesting and roosting seabirds, occupy the upper level of the mangrove plants, while marine animals occupy the bases . Sessile marine organisms such as bamacles, oysters, and sponges arc dependent upon the hard surfaces provided by the mangrove roots, while mobile animals such as crabs, gastropod molluscs, shrimps, and !ish occupy the mud around the stilt roots and the water in the tidal creeks. In the Caribbean region, only 4 common mangrove species arc present, tar fewer than in the Indo-Pacific region where some 44 species occur. Mangroves arc lbund along sheltered coastlines of almost all countries and territories SUITounding the Caribbean Sea, and they fullil important socioeconomic and environmental functions. These include the provision of a large variety of wood and non-wood forest products; coastal protection against the effects or wind, waves, and water cunents; conservation of biological diversity·--·including a number of endangered mammals, reptiles, amphibians, and birds; protection of coral reels, scagrass beds, and shipping lanes against siltation; and provision or habitat, spawning grounds, and nutrients lbr a variety of lish and shclllish, including many commercial species. Mangroves can provide income as ceo-tourist attractions lbr viewing birds, manatees, crocodiles, and other fauna and llora. High population pressure in coastal areas has, however, led to the conversion or many mangrove areas to other uses, including infrastructure, aquaculture, rice, and salt production. Numerous case studies describe mangrove losses over time, but information on the status and trends of mangrove area exlenl at the global level is scarce. A comprehensive database on mangrove extent has been assembled by the UN Food and Agriculture Organisation (FAO 2002, 2003a). This contains a compilation of mangrove area estimates by country along with revised estimates lor 1980, 1990, and 2000 for each country (Table 2.2). The results of the trend analyses indicate that the mangrove area around the Caribbean Sea has in general decreased by about 1% per year since 1980. Table 2.2 also shows that the region of Central America and the Caribbean has lost about 413,000 ha of mangroves since 1980, but that the rate of loss seems to have slowed from about 1.4% per annum between 1980 and 1990 to 1.1% from 1990 to 2000. The highest rates of dclbrestntion in the 1980s were found in Barbados, Jamaica, Dominica, and Honduras, while the same countries plus Dominican Republic, El Salvador, Haiti, and Honduras had the greatest rate in the 1990s. -36-