Southern Florida, Florida Keys, 7,800 mi2 (20,200 km2)
Land-surface form.--The Everglades occupy an extensive, almost flat marl and limestone shelf generally covered with a few feet of muck and a little sand. Elevation ranges from sea level to 25 ft (7.6 m). The low, level coastal plain contains large areas of swamps and marshes, with low beach ridges and dunes rising several feet above them. Poorly defined broad streams, canals, and ditches drain into the ocean. In the interior, hammocks rise a few feet above the general area.
The flat, marshy surface of the Florida Everglades. (Photo: National Park Service.)
Climate.--Average annual temperatures in this tropical climate range from 70 to 75F (21 to 24C), with minimums from October to February. The area is frost-free practically all year. An average of 50 to 65 in (1,280 to 1,660 mm) of rain falls per year, mostly between late spring and the middle of autumn.
Vegetation.--About one-fifth of the area is covered by tropical moist hardwood forest. Cypress forests are most extensive, but mangrove is widespread along the eastern and southern coasts. Much of the area is open marsh covered by phreatophytic grasses, reeds, sedges, and other aquatic herbaceous plants. Several areas covered by dense grasses are classified as medium-tall grasslands, with sawgrass and three-awns as major plants. Within these grasslands there are mesic habitats called "hammocks" that rise above the surrounding, usually wetter areas. These hammocks contain groves of low to medium-tall broadleaf evergreen trees and shrubs. Mahogany, redbay, and several palmettos are common. One also finds strangler fig and abundant epiphytes.
Soils.--Histosols are the principal soils. In slightly less wet parts of the southern Everglades, Inceptisols occupy extensive areas.
Fauna.--The Everglades have a wide variety of influent species from adjacent areas of palmetto prairie, cypress swamp, magnolia forest, and mangrove. Slight changes in water level create substantial changes in habitat and fauna.
Among the many mammals found are whitetail deer, Florida panther, black bear, raccoon, bobcat, opossum, skunk, various bats, marsh and swamp rabbits, cotton rat, and fox squirrel. Manatees inhabit estuaries and interlacing channels.
Numerous species of birds live in this province. Before the water level in much of the Everglades was lowered by drainage, the area was home to large numbers of herons, egrets, limpkins, mottled ducks, Florida Everglade kites (snail kites), and other birds. The Florida Everglade kite is now classified as endangered.
Characteristic lizards are the Caroline anole and the brown red-tailed skink. The rough green snake, key rat snake, and southern Florida coral snake are found here. The endangered American alligator is a year-round resident.