structural:summarization
Sawgrass marshes and sloughs

Several ecosystems are present in the Everglades, and boundaries between them are subtle or absent. The primary feature of the Everglades is the sawgrass marsh. The iconic water and sawgrass combination in the shallow river 100 miles (160 km) long and 60 miles (97 km) wide that spans from Lake Okeechobee to Florida Bay is often referred to as the "true Everglades" or just "the Glades". Prior to the first drainage attempts in 1905, the sheetflow occupied nearly a third of the lower Florida peninsula. Sawgrass thrives in the slowly moving water, but may die in unusually deep floods if oxygen is unable to reach its roots. It is particularly vulnerable immediately after a fire. The hydroperiod for the marsh is at least nine months, and can last longer. Where sawgrass grows densely, few animals or other plants live, although alligators choose these locations for nesting. Where there is more room, periphyton grows. Periphyton supports larval insects and amphibians, which in turn are consumed as food by birds, fish, and reptiles. It also absorbs calcium from water, which adds to the calcitic composition of the marl.

Sloughs, or free-flowing channels of water, develop in between sawgrass prairies. Sloughs are about 3 feet (0.91 m) deeper than sawgrass marshes, and may stay flooded for at least 11 months out of the year and sometimes multiple years in a row. Aquatic animals such as turtles, alligators, snakes, and fish thrive in sloughs; they usually feed on aquatic invertebrates. Submerged and floating plants grow here, such as bladderwort (Utricularia), waterlily (Nymphaeaceae), and spatterdock (Nuphar lutea). Major sloughs in the Everglades system include the Shark River Slough flowing out to Florida Bay, Lostmans River Slough bordering The Big Cypress, and Taylor Slough in the eastern Everglades.

Wet prairies are slightly elevated like sawgrass marshes, but with greater plant diversity. The surface is covered in water only three to seven months of the year, and the water is, on average, shallow at only 4 inches (10 cm) deep. When flooded, the marl can support a variety of water plants. Solution holes, or deep pits where the limestone has worn away, may remain flooded even when the prairies are dry, and they support aquatic invertebrates such as crayfish and snails, and larval amphibians which feed young wading birds. These regions tend to border between sloughs and sawgrass marshes.

Alligators have created a niche in wet prairies. With their claws and snouts they dig at low spots and create ponds free of vegetation that remain submerged throughout the dry season. Alligator holes are integral to the survival of aquatic invertebrates, turtles, fish, small mammals, and birds during extended drought periods. The alligators then feed upon some of the animals that come to the hole.