Home Introduction Physical Setting Urbanization Natural Hazards Mineral Resources Water System Environmental Quality Outdoor Recreation Everglades N.P. Coastal Zone Fish & Wildlife > Estuaries - Endangered Species - Recreation - Exotic Species Miccosukee Indians Conclusion References

Estuaries are tidal reaches where sea and stream mingle. The fresh water that meets the sea in the estuarine zone of Dade County came from the Everglades and the coastal marshes. Within this estuary are the wide seagrass flats and dense mangrove forests of the tidal zone. Large areas are constantly covered by shallow water, and salt content is less than that of the sea because of the seasonal inflow of fresh water.

This estuarine complex is very fertile. Fresh water with suspended material from the land-dissolved nutrients, humus, top soil-is mixed by the tides with mineral-rich sea water and organic products of underwater decay that currents prevent from settling on the bottom. This fertility is enhanced by the warmth of a subtropical climate. The Dade County estuary complex is more productive than the best Midwestern farmland.

The estuaries furnish a sheltered environment for small and microscopic plant and animal life which forms the abundant food for successively higher links in the food chain. The rich nutrients developed in the estuary are moved through the mats of underwater sea plants on the bay side and around the shallow mangrove flats on the land side by tidal currents.

Much of the life of our coastal seas begins in and depends on such estuaries. They are, for the sea, the cradle of life.

The value of the Dade County estuaries as spawning grounds, nurseries, or growing-up places for myriads of important commercial species such as shell fish, crustaceans, and finfishes cannot be over emphasized. Rarely are nature and the modern urban conglomerate in such close juxtaposition as in the estuaries of Dade County. The amenities which arise from this estuarine zone attract millions of people to the area. But this zone is most severely impacted.

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Predevelopment		Postdevelopment

The limited resources of the Dade County estuaries, as a foundation for economic growth, are endangered by dredging and pollution. The transition from use to overuse is subtle. At first, a few fish die. An oil spill kills a thousand birds. Completely unnoticed are the millions or billions of plankton which die as a result of some toxic discharge into the bay. The loss of plankton in a localized area changes the species composition of fish, which in turn, changes the species composition of birds and other higher forms dependent upon them. Then, people are directly affected: a beach area is closed for a few days or months. These subtle effects result in gradual environmental degradation which can eventually spoil the area.

Urban development is not subtle. It can destroy much of the estuaries’ attractiveness and eliminate the habitat of thousands of wild things. Some, like the manatee, the southern bald eagle, and the great white heron, are already being pushed back by such encroachment.

If habitat losses along the Dade County coast continue at the same rate as in the recent past, the estuarine values which contribute much to the economy and attractiveness of south Florida will be lost. The thin line of higher land consisting of the beach, dunes, and near shore areas of the coast is the most desirable for development. This type of land has been almost entirely converted to urban uses. Of the original 12,600 acres, 92 percent has been lost to urban development. Only 1,000 acres remain undeveloped. As the higher land is used up, mangrove areas become increasingly desirable, and are bulkheaded, filled with dredge, and made into real estate. Of the 99,700 acres of estuary, mostly mangrove forest, in Dade County, 15,400 acres, or about 15 percent, has already been lost as productive estuarine habitat.

Florida law (the Randall Act) requires that development in an estuarine area receive careful biological assessment by the Department of Natural Resources. Recommendations are made to the Trustees of the Internal Improvement Trust Fund who may deny or grant a permit to develop within the estuarine zone. The Fish and Wildlife Coordination Act also requires that the Bureau of Sport Fisheries and Wildlife evaluate the development and make recommendations before any federally required permits are granted.

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