The Everglades are a singular environment - one of a kind of all the world. The Everglades are host to extremely varied micro-environments where tiny increments completely change the nature of the system.
Variety of Habitats.From the Shark River Slough to Florida Bay, the Everglades is home to a variety of habitats. Slight changes in elevation (only inches), water salinity, and soil create entirely different landscapes, each with its own community of plants and animals.
The Everglades is a low, flat plain shaped by the action of water and weather. In the summer wet season it is a wide, grassy river. In the winter season the edge of the slough is a dry grassland. Though Everglades National Park is often characterized as a water marsh, several very distinct habitats exist within its boundaries.
Marine/Estuarine
Florida Bay, the largest body of water within Everglades National Park, contains over 800 square miles (2072 square km) of marine bottom, much of which is covered by seagrass. The seagrass shelters fish and shellfish and sustains the food chain that supports all higher vertebrates in the bay. The hard bottom areas are home to corals and sponges.Mangroves
Mangrove forests are found in the coastal channels and winding rivers around the tip of South Florida. Red mangroves (Rhizophora mangle), identified by their stilt-like roots, and the black (Avicennia germinans) and white mangroves (Laguncularia racemosa) thrive in tidal waters, where freshwater from the Everglades mixes with saltwater. This estuary system is a valuable nursery for shrimp and fish. During the dry months, wading birds congregate here to feed. Many bird species nest in the mangrove trees.
Coastal Prairie
Located between the tidal mud flats of Florida Bay and dry land, the coastal prairie is an arid region of salt-tolerant vegetation periodically flooded by hurricane waves and buffeted by heavy winds. It is characterized by succulents and other low-growing desert plants that can withstand the harsh conditions.
Freshwater Marl Prairie
Bordering the deeper sloughs are large prairies with marl sediments, a calcareous material that settles on the limestone. The marl allows slow seepage of the water but not drainage. Though the sawgrass is not as tall and the water is not as deep, freshwater marl prairies look a lot like freshwater sloughs.
Freshwater Slough
The slough is the deeper and faster-flowing center of a broad marshy river. This "fast" flow moves at a leisurely pace of 100 feet (30 meters) per day. Dotted with tree-islands called hammocks or heads, this vast landscape channels life-giving waters from north to south. Everglades National Park contains two distinct sloughs: Shark River Slough, the "river of grass;" and Taylor Slough, a narrow, eastern branch of the "river." There are no surface connections between the two. A series of other sloughs through the Big Cypress Swamp supply freshwater to western Florida Bay and the Ten Thousand Islands.
Cypress
The cypress tree (Taxodium spp.) is a deciduous conifer that can survive in standing water. These trees often form dense clusters called cypress domes in natural water-filled depressions. The trees in the deep soil at the center grow taller than those on the outside. Stunted cypress trees, called dwarf cypress, grow thinly-distributed in poor soil on drier land.
Hardwood Hammocks
Hammocks are dense stands of hardwood trees that grow on natural rises of only a few inches in the land. They appear as teardrop-shaped islands shaped by the flow of water in the middle of the slough. Many tropical species such as mahogany (Swietenia mahogoni), gumbo limbo (Bursera simaruba), and cocoplum (Chrysobalanus icaco) grow alongside the more familiar temperate species of live oak (Quercus virginiana), red maple (Acer rubum), and hackberry (Celtis laevigata). Because of their slight elevation, hammocks rarely flood. Acids from decaying plants dissolve the limestone around each tree island, creating a natural moat that protects the hammock plants from fire. Shaded from the sun by the tall trees, ferns and airplants thrive in the moisture-laden air inside the hammock.
Pinelands
The slash pine (Pinus elliottii var. densa) is the dominant plant in this dry, rugged terrain that sits on top of a limestone ridge. The pines root in any crack or crevice where soil collects in the jagged bedrock. Fire is an essential condition for survival of the pine community, clearing out the faster-growing hardwoods that would block light to the pine seedlings. Pine bark is multi-layered, so only the outer bark is scorched during fires. The pinelands are the most diverse habitat in the Everglades, consisting of slash pine firest, an understory of saw palmettos (Serenoa repens), and over 200 varieties of tropical plants.Water Management.
National parks are not islands of land. Outside events shape their fates. Water management is the critical issue for the Everglades, whose watershed begins in central Florida''s Kissimmee River basin. Summer storms flooding there once started a shallow, wide river flowing southward to the Gulf of Mexico. Elaborate water controls now disrupt the natural flow. Short of clean water at critical seasons, and in the correct quantities, the Everglades will die.
South Florida''s freshwater supply comes from rain on the Kissimmee River basin and southward, mostly in May through October. Evaporation, transpiration, and runoff consume 4/5 of the rain, which may total 40 to 65 inches (100 to 165 cm) per year.
Slow and rain-driven, the natural cycle of freshwater circulation historically built up in shallow Lake Okeechobee. It averages 12 feet (3.7 meters) deep and covers 730 square miles (1890 square kilometers).
Thus began the flow of the wide, shallow "River of Grass." Fifty miles (80 km) wide in places, one to three feet (0.3 to 0.9 meters) deep in the slough''s center but only 6 inches (15 cm) deep elsewhere, it flowed south 100 feet (30 meters) per day across Everglades sawgrass toward mangrove estuaries of the Gulf of Mexico. A six-month dry season followed.
Everglades plants and animals are adapted to alternating wet and dry seasons. Water cycle disruptions ruin crucial feeding and nesting conditions.
During the dry season (December to April), water levels gradually drop. Fish migrate to deeper pools. Birds, alligators, and other predators concentrate around the pools to feed on a varied menu of fish, amphibians, and reptiles. This abundant food source is vital to many wading birds who are nesting during the dry season.
In May, spring thunderstorms signal the beginning of the wet season. A winter landscape dotted with pools of water yields to a summer landscape almost completely covered with water. Wildlife disperses throughout the park. Insects, fish, and alligators repopulate the ''glades, thus replenishing the food chain. By December, the rains cease and the dry cycle begins again.
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