Freshwater Marsh.

If there is one ecosystem that symbolizes Florida’s landscape it is the “Everglades”, an immense fresh water marsh that covers 4000 square miles of the Southern tip of Florida. The definition of a marsh is a shallow wetland with few trees and standing water for most of the year (long hydroperiod).

The Everglades, called Pa-hay-okee (“grassy waters”) by the natives, begins as an overflow from lake Okeechobee in central Florida. The water then flows southward and westward in a slow fashion through the Everglades until it escapes into Florida Bay. The slope of the Everglades is 2 in per mile so the water flow is relatively slow. This slow moving “water mass” provides a unique ecosystem found nowhere else on earth.

A healthy marsh can support abundant life, including Sawgrass (Cladium jamaicense) up to 10 feet tall, immense flocks of wading birds, fish, exotic plants, alligators, and numerous invertebrates. The dominant grass found in freshwater marsh is unquestionably Sawgrass (actually a sedge, not a grass), although other species of grasses occur as well.

Along this route to the sea, the Everglades consists of mile after mile of Sawgrass marsh interrupted occasionally by Hardwood Hammocks that develop where the ground is slightly elevated and fresh water sloughs which are the deepest and most permanent areas in the marsh. Examples of sloughs are Taylor slough and Eco Pond.

Within the freshwater marsh are slightly deeper areas created by Alligators (Alligator mississippiensis) called “alligator holes”, which are critical for the survival of many aquatic species during prolonged dry spells. Because freshwater marshes are usually underwater it is difficult for terrestrial herbivores to feed on the vegetation. Because of this the Florida Apple Snail (Pomacea paludosa), a semi aquatic gastropod that thrives on Sawgrass, is the ideal herbivore in this environment. This snail is the primary food source for a number of birds, including the Limpkin (Aramus guarauna) and the Snail Kite (Rostrhamus sociabilis). Evidence of this predation (snail shells) can be seen all over the marsh.

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References

Alden, P., R. Cech, and G. Nelson. 1998. National Audobon Society Field Guide to Florida. New York: Alfred A. Knopf Inc.

Lodge, T.E. 1998. The Everglades Handbook: Understanding the Ecosystem. Boca Raton: St. Lucie Press.