publications > paper > PP 1011 > ecosystems > freshwater and terrestrial > wet prairies
Ecosystems of south Florida
Freshwater and terrestrial ecosystems
Wet prairies are seasonally inundated lands intermediate in depth
and periods of flooding between sawgrass marshes and sloughs. Characteristic plants include the algal components of periphyton, and a variety of vascular plants such as maidencane, spikerush, beakrush, and water dropwort. Soil in the prairies is usually a calcareous marl, which is precipitated, at least in part, by green and blue-green algae and other microorganisms in the periphyton.
During the wet season, animals of the wet prairies include an assemblage of aquatic and semiaquatic species similar to those of the sloughs. As water levels fall in the dry season, the aquatic animals such as the freshwater prawns and fish are forced into the deeper sloughs and ponds. Water levels rarely recede more than a foot below the land surface except in abnormally dry years (Loveless, 1959).
Wet prairies occur throughout the Everglades, in parts of the Big Cypress Swamp, and in the sandy flatlands, particularly the Devils Garden area. In the Everglades they occupy large areas called "flats," which are extensive on the boundaries of Shark River Slough and the northwest Everglades. In the Big Cypress Swamp, wet prairies occur as flats and as small, isolated areas associated with ponds and marshes. In the flatlands they are characteristically small areas associated with bedrock depressions in the pine forests and dry prairies.
Wet prairies have suffered alteration and destruction since 1900. About 1,300 km2 (500 mi2) have been destroyed, including most of the wet prairies immediately west of the Atlantic Coastal Ridge (Birnhak and Crowder, 1974). In Broward and Palm Beach Counties alone, 80 percent of the wet prairies were destroyed (Birnhak and Crowder, 1974). Alteration - through drainage, water impoundment, and the spread of exotic plant species--has also been extensive in the remaining wet prairies. In the western Big Cypress Swamp, drainage for urban development has suppressed periphyton production and affected all levels of the food web dependent on this production (Carter and others, 1973). In the central Everglades, wet prairies have been affected recently as a result of changes in water impoundment in the conservation areas (fig. 11). In the mid-1950's, wet prairies were common in the central and east-central parts of Conservation Area 2 and in the west and south sections of Conservation Area 3, as indicated by extensive stands of water rush and maidencane (Loveless, 1959). Before the construction of Levee 35, west of Fort Lauderdale, in 1961, much of Conservation Area 1 went dry annually; after construction the area remained flooded. Similarly, the south part of Conservation Area 3 has remained flooded for long periods as a result of levee completion in 1962. As a result of changes in impoundment, wet prairies have been mostly eliminated in Conservation Area 2 and reduced in Conservation Area 3 (Dineen, 1972) but have been increased in parts of Conservation Area 1 (Hagenbuck and others, 1974).
|A periphyton mat at the water surface is typical of Everglades wet prairies. [larger image]
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