Caribbean
Water defines the low-lying lands of South Florida and the Keys, which share a subtropical flora and fauna with the Caribbean islands. The population boom here has increasingly altered natural flows, consumed developable land, and boosted demand for water, raising the threat to the region’s keystone natural system—the Everglades. Rainfall alone supplies the water for this vast wetland, creating the unique "sheet flow" of water over broad, shallow marshes that led Marjory Stoneman Douglas to dub it “a river of grass.”
Location
Within the United States, the Caribbean Ecological Division encompasses south Florida, primarily from the Everglades south, including the Florida Keys. This Division also includes all of the Greater and Lesser Antilles.
Climate
Humid tropical, with average temperatures of 24.8ºC (77ºF) and annual rainfall of 1480mm (58 inches). The Everglades portion are subtropical, meaning the climate is not quite as hot and wet as the tropics, but the area still gets a large amount of rainfall. The region is also exposed to hurricanes, most frequently between August and October.
Features
The Everglades have suffered from a long history of human manipulation. Wetlands have been drained and cleared, rivers straightened and canals ditched, all of which which affect foraging areas for wading birds. Changing natural water levels also makes fire more likely. Today, it is estimated that only 2 percent of the original ecosystem is truly intact. This is important because, unlike other great wetlands, the Everglades derives its water directly from rainfall. The occasional small hills that rise above the wetland are called hammocks, and it is here that clusters of trees that need drier areas can grow. Species growing on these tree islands include red bay, pond apple, cypress, and a variety of palms. Some tree snails are endemic to the hammocks.
History and Trends
Florida is one of the fastest-growing states in terms of human population; between 1940 and 1980, the populations of Dade, Broward, and West Palm Beach Counties increased by 830 percent! This puts great stress on the Everglades, especially through the use of water. So much land has been cleared for agriculture and urban development in the Miami area and the Florida Keys that the South Florida Rocklands that once existed are now almost entirely gone. Only about 2 percent of the original habitat remains in small, isolated fragments surrounded by water or cities -- some patches even between highways.
As the human population continues to grow, we increasingly want to control and stop the fires that are essential to the survival of the pine forests. What's more, exotic plants such as Brazilian pepper threaten to outcompete native plants, and an increase in the water table from irrigation kills the pines. Taken together, these factors make the ecoregion very vulnerable to natural disturbances such as hurricanes.
Caribbean Ecoregions
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Tropical Florida Ecoregion
Surrounded by the Gulf of Mexico to its west, the Atlantic Ocean to its east and the Florida Straits to its south, Tropical Florida is a landscape under siege. It is also a landscape of great contrasts between highly fragmented upland terrestrial ecological communities-systems and vast expanses of herbaceous wetlands.