The most extensive natural community in the management area is sawgrass marsh. The dominant species sawgrass, which reaches heights of 10 feet high or more, thrived in the low-nutrient and fluctuating water conditions of the historic Everglades.
The black peat of the Everglades valued for agriculture, especially sugar cane, formed over thousands of years from decaying sawgrass and charcoal from frequent light ground fires. Today water levels in the marsh are regulated by water control structures as well as by rainfall and vary from an average of 2 feet deep at the peak of the wet season in October to below ground level at the end of the dry season in May. Sawgrass is important to ground nesting birds such as the American and least bitterns, which build elevated mound nests out of dead vegetation and use the thick growth of sawgrass for cover.
Fires every one to five years are typical and result from lightning in the late spring when the ground surface is dry, although sawgrass will carry a fire over water. When the peat dries out in extreme droughts, muck fires may consume the soil and lower the ground surface converting the sawgrass marsh to a slough.
Tree islands comprise less than two percent of the area but are an integral part of the Everglades ecosystem. These islands vary in size from less than an acre to several hundred acres. Eighty percent of Everglades plant diversity is found on tree islands. They are also critical habitat for deer, Florida panther, bobcat, raccoon, marsh rabbit, river otter, snakes, migratory songbirds, small mammals, and butterflies, and nesting sites for wading birds, alligators, turtles, and raptors. Dominant species are maple, dahoon holly, wax myrtle, elderberry, and willow.
The wet prairies of the Everglades are treeless plains with a sparse to dense ground cover of grasses and herbs, including maidencane, spikerush and beakrush. Other typical plants include swamp lily, arrowhead, pickerel weed, Ludwigia spp. and bladderwort. Wet prairies occur on low, relatively flat, poorly drained terrain. They are saturated approximately 90 percent of the year and burn every six to ten years. Sloughs within the Everglades are broad shallow channels inundated with flowing water except during extreme droughts. They often correspond with linear depressions in underlying bedrock. Vegetation consists of large emergent herbs and floating aquatic plants such as white water lily, floating hearts and spadderdock. During the rainy season, sloughs and wet prairies are habitat for a wide variety of fish species as well as snails, crayfish and other invertebrates. As water levels decline during the dry season, fish and invertebrates move to deep water sloughs for refuge. This high concentration of prey during the dry season is a critical source of food for the threatened wood stork and other wading birds. Wet prairies and sloughs are threatened by the spread of melaleuca and cattails.