What is a Wetland?

The term "wetland" is a very good description of many natural areas that we have here in Florida. Wetlands are a combination of water and land. They are much like a natural water-treatment plant, trapping much of the silt and sediment carried by rivers which flow through the wetlands. Most wetland areas have lush growths of plant life, both trees and grasses.

There are several different types of wetlands. Estuaries, salt marshes, swamps and mangroves make up the largest part of our wetlands in Florida. The amount of wetlands in Florida is amazing when viewed from the air. If one flies over Levy, Dixie, and Lafayette Counties, one sees that swamp black gum, and cypress ponds and swamps cover from 25 to 60 percent of the total land area. Wetlands cover large areas of Wakulla, Liberty, and Franklin Counties. The Big Cypress of Collier County and the Green Swamp of Polk, Lake, Sumter, Hernando and Pasco Counties are major water supply sources. The Suwanee and St. Mary's Rivers are derived from the Okefenokee Swamp in southern Georgia and northern Florida. (Forested Wetlands of Florida, June 1977)

Without wetlands, the climate would otherwise produce barren white sandy areas like those at Cape Coral. River and creek swamps have the capacity to absorb heavy floods. Mangrove wetlands bathed with tidal and river exchanges hold the soil, protect against hurricanes, and provide nutrition for fisheries and wildlife. A "wetland" is then described as "land where water is the dominant factor determining the nature of soil development and the types of plant and animal communities living in the soil and on its surface." (Our Nation's Wetlands, 1978).

Importance of Wetlands

Purification Plant

The grasses and trees that grow in wetland areas trap solid particles that are in the water. Many wetland areas are important in the breakdown of organic waste materials, a process which also helps to clean the water. Bacteria, and other microorganisms that live on the roots of grasses and trees, eat and digest the organic wastes that are brought into the wetlands. Tidal action and/or river water carries the cleansed water toward the ocean. As the water flows nearer the ocean, the tides act as a flushing mechanism, pumping the clean water out into the sea and receiving more river water containing silt and organic wastes. Many wetland areas act as a "purification plant" for the sea.

Nursery

A wetland is a unique hatching and breeding area for many aquatic animals. The eggs of many species of aquatic animals drift into the wetlands. Here, the eggs hatch and the young grow up. The wetlands provide shelter for these small animals.

The adults of many marine species leave the protection of the wetlands only when they swim to the ocean to spawn. These animals are known as wetland dependent animals. Fish, crabs, and shrimp are just a few of the wetland dependent animals. Some fish such as snapper live most of their lives and spawn in the open ocean, but the younger snapper live the first part of their lives in the wetlands. Since the younger are dependent on the wetlands for protection and food, the snapper as a whole are also said to be wetland dependent.

Both sport fish and commercial fish are considered by many to be a renewable resourcewhich is dependent on wetlands. A renewable resource is one which is produced on a continuing basis so that a new "crop" is available later on. This means that the wetlands are constantly supplying the oceans with shrimp, crabs, lobsters, fish and many other very important marine animals. If it were not for our wetlands, many of the foods we get from the oceans would not be around very long.

Nutrients

Nutrients for plant growth are plentiful in wetlands from land runoff and from the grasses. Abundant food is available for animals. Grasses such as cordgrass (Spartina), turtle grass (Thalassia) and eelgrass (Zostera) provide homes, protective cover and food for the many different animals that inhabit a wetland. Wetlands are collecting and dispersal areas for nutrients. Nutrients from the grasses and from the land runoff make up the first (basic) link in the food chain of the wetlands. The basic providers of nutrients in a wetland are the grasses and land runoffs.

Estuaries

An estuary is an area where the salt water of the seas and the fresh water of rivers and streams meet and mix. As sea water is moved into this area by tides, the saltiness is diluted by fresh water flowing toward the sea. This mixture of salt water and fresh water is often called brackish water. An estuary, then, has some characteristics of the ocean and some of the characteristics of the fresh water. It is a very special environment.

Compared to the oceans, estuaries comprise only a small percentage of the total surface of the marine world. Though esuaries are small in size, they are large in productivity. The rivers and streams that drain into an estuary bring fertilizing minerals (nutrients) from the land. Marsh grasses, mangroves, seagrasses, seaweeds (algae), and microscopic algae (phytoplankton) manufacture food from the nutrients.

An estuary has a rich supply of food, and the built-in protection from the predators makes it a haven for small animals. Some animals such as worms, oyster, mussels and barnacles spend their entire lives in an estuary. Other animals such as shrimp, mullet and blue crabs spend only a part of their lives in an estuary. The rest of the time may be spent in either the fresh water of the river or the salt water of the sea.

The many small animals that live in the protective confines of an estuary will soon grow up and become adults. The shallow water and submerged plants provide excellent hiding places from larger, hungry fish. Because so many different kinds of young sea animals live and feed in an estuary, it is often referred to as a nursery.

Salt Marshes

Salt marshes are low coastal lands which are strongly influenced by the tide. Salt marshes are usually covered with marsh grasses called cordgrass. These grasses usually grove up in an estuary where the rising tidal water comes up to cover the flat land. As the tide falls, the marsh land is exposed to the air.

Swamps

A swamp is an area that usually is further inland from the ocean than are estuaries and salt marshes. Swamps are less influenced by the constant rise and fall of the tide. Nevertheless, the tidal water and/or river water which flows though the swamp brings silt and organic material into the swamp. Like estuaries and marshes, swamps are lowland areas saturated with water. Swamps are often mistaken for marshes, and vice versa. Actually, the two are as different as a forest and a prairie. It is quite easy to tell the difference between a swamp and a marsh. The dominating feature of a swamp is trees while that of a marsh is grass.

In a swamp can be found plants such as palm trees, oak trees, palmettos and grasses. Alligators, herons, bass, trout, and bull frogs are some of the animal members of the swamp community. Swamps and marshes are sometimes very close to one another and usually intermingle. In many places in Florida, marshes encricle wooded islands known as "hammocks."

Mangrove Wetlands

In Florida, mangrove wetlands contain four species of trees that develop swamps in a variety of coastal situations. The four are red mangrove, black mangrove, white mangrove, and the buttonwood (buttonbush). Mangroves are indicators of a salt water environment, and natural stands are never found without salt water intrusion. Organisms such as gastropods, crabs, tunicates, oysters, clams, algae, worms, anemones and sponges take refuge on the prop roots of mangroves. It is the roots of the mangroves where small-sized offspring of salt water, brackish and fresh water animals find shelter, food, and a place to grove up. "By maintaining mangrove intact, man assures himself a multiplicity of free services in wildlife, panorama, environmental quality, and the form of food from the sea, forest products, above all, services in the form of water quality control and protecton from floods, storms and other hazardous climatic events. When taken collectively, these services may outweigh benefits from any other use man can imagine for these areas where mangroves grove." (Forested Wetlands of Florida - Their Management and Use).

The Florida Everglades

The Florida Everglades is a very large wetland in the southern part of Florida. The Everglades wetlands are sometimes referred to as an ocean of grass. The Everglades is the largest bredding and nursery area for many marine animals in the United States. This area houses one of the largest food webs in the world. The adult marine animals which depend on the Everglades when young are worth several million dollars in our seafood industry. Rainwater is the main source of water in the Everglades. The water is absorbed in the swamps of the Everglades and seeps into the rivers that flow to the ocean. Large pools scattered throughout the grassy Everglades supply homes for large aquatic animals such as alligators, bass, tarpon and birds.

The Florida Keys

The Florida Keys in another wetland area that provides a place for ocean animals to feed and grow. This area is one of the largest breeding and nursery grounds in the state of Florida. Pink shrimp (Panaeus Duorarum) are abundant in the keys. These shrimp spend the early months of their lives in the numerous estuaries and marshes of this region.

The islands of the keys constitute a perfect environment for the shrimp. Many marshland areas of the Florida Keys have been devastated by land-fills and dredging. Many areas that once were estuaries and marshes are now places where hotels, motels and mobile home lots stand. While dredging does not totally destroy a wetland, the wetland plants and animals are drastically limited. Plants and marine animals are killed. Larger quantities of silt gush into the rivers and settle on nearby grasslands and coral reefs. As the silt settles, the grasslands and corals are suffocated and soon die.

Wetlands and Landfills

The commercial harvesting of marine animals linked with mangrove wetlands is quite impressive. A study done in 1968 showed that 15.7 million dollars worth of shrimp, 1 million dollars worth of spotted sea trout and 1.2 million dollars worth of blue crabs were caught in one year. These are only a few of the animals that are dependent upon mangroves. Almost two-thirds of the total catch of fish and shellfish in the United States spend a portion of their lives in wetland areas, which is why the wetlands are often called the "nurseries of the sea." Wetland swamps, marshes, estuaries and mangroves are being filled in by dredging, clearing out of land, bulkheading, and landfills. These operations greatly decrease the area available to the newly hatched animals. Wetland acreage in the United States has been reducedat the rate of 300,000 acres per year (Pollard,1976).

Several million acres of the Everglades have been filled in by "land developers." The valubale, swampy ground is scraped and pushed back. Low lying areas are filled in and built up above sea level. This landfill kills grasses and mangroves upon which the marine animals depend. The space that the plants and animals can inhabit is constantly being decreased.

Films for Loan

Estuarine Heritage - 28 Min., Color. Stresses the importance of estuaries for important species such as shrimp, crab, oysters, clams, menhaden, and other finfish; as the habitat of waterfowl and furbearing animals; and as a recreational and esthetic resource. Depicts major threats to estuarine resources: pesticides, municipal methods of conservation.

The Biologist and the Boy - 14 Min., Color. A popularized, shortened version of Estuarine Heritage, both of which are produced in cooperation with the five states bordering the Gulf of Mexico. Based on an encounter between a youngster intent only on fishing and fun, and a biologist who shares with the boy his more knowledgeable perspective and sense of responsibility for conservation. Distributed theatrically as Crisis on the Coast.

Mail Request To:

Department of Commerce - NOM

Motion Picture Service

12231 Wilkins Avenue

Rockville, Maryland 20852

Big Cypress, Partnership with Nature - 17 min., Color. Deals with the Big Cypress swamp in Florida, which is an exotic haven for fish, birds, and creatures rarely seen. It is also the site of an oil discovery. The film takes a look at the successful efforts that are being made to preserve the wild beauty of the swamp, while tapping the area's much-needed energy reserves.

Mail Request To:

EXXON Company

Modern Talking Picture Service

2323 New Hyde Park Road

New Hyde Park, N.Y. 11040

Islands of Green - 24 min., Color. Shows how the National Audubon Society is helping communities across the country establish nature education centers, to counteract the influences of a totally man-made environment. People isolated within cities are led to see nature around them and to understand it with an awareness, appreciation, and affection for the natural world and to enjoy and preserve what land remains.

Mail Request To:

ASSOCIATION FILMS, INC.

866 Third Avenue

New York, N.Y. 10022 or

ASSOCIATION FILMS, INC.

5797 New Peachtree Road

Atlanta, Georgia 30340

A Living Lake - 14 min., Color. Chemical and biological studies of Lake Okeechobee. Features the scientific work of the South Florida Water Management District in protecting and monitoring Lake Okeechobee which is the heart of the water supply for all of South Florida.

Mail Request To:

South Florida Water Management District

P. 0. Box 5

West Palm Beach, Florida 33402

Billion Dollar Marsh - 45 Min. (long version) 26 Min. (short version). Stretching over 2,500 miles from Maine to Florida lies one of the greatest areas of marshland in the world. To developers, these marshes are so many thousands of wasted acres that could be drained for housing and industry; to others, the marsh must be preserved as is. This film, shot in the wetlands of New Jersey, Virginia and Georgia, explores the conflicting points of view.

The Salt Marshes - The importance of the salt marsh and the role it plays in the delicate ecosystem isdepicted in this film. How a marsh is formed and the variety of plants and animals that inhabit the marsh are also described.

Mail Request To:

VIMS/SEA GRANT MARINE EDUCATION CENTER

Virginia Institute of Marine Service

Gloucester Point, Virginia 23062

804/642-2111 Ext.111

References

"Estuaries must be protected," Australian Fisheries, D. A. Pollard, June, 1976

Estuary Ecology Christopher M. Dewes, and Jon K. Hooper, California Sea Grant Marine Advisory Publication, 75-LE/2245.

Forested Wetlands of Florida - Their Management and Use, Center for Wetlands, Phelps Lab., University of Florida, Gainesville, Florida, June 1977.

Land-building and Stabilization by Mangroves, Jeffrey M. Carlton, Contribution No. 240, Florida Department of Natural Resources Marine Research Laboratory, St. Petersburg, Florida.

Life In And Around The Salt Marshes, Michael J, Ursin, Thomas Y. Crowell Company, New York, 1972.

"Meanders in the marsh," Audubon George Reiger, September, 1977.

Our Nation's Wetlands, An Interagency Task Force Report, Elinor Lander Horwitz, U.S. Government Printing Office, Washington, D.C. 20402, 1978.

"South Florida's Mangrove-Bordered Estuaries: Their Role in Sport and Commercial Fish Production," University of Miami Sea Grant Information Bulletin, No.4, December, 1970.

"Tidal Wetlands," Wavelets, Gene Silberhorn, Marine School House Series No. 5, Sea Grant Marine Advisory Services, Virginia institute of Marine Science.

The Estuary. Florida Department of Natural Resources Marine Research Laboratory, St. Petersburg, Florida, 33701.

The Ocean World of Jacques Cousteau, The Sea in Danger, Vol. 19, The Danbury Press, pp. 84-85, 1973.

Tropical Marine Invertebrates of Southern Florida and the Bahama Islands, Warren Zeiller, John Wiley & Sons, Inc., New York, 1974.

Wildlife of Lakes, Streams, and Marshes, H.R. Morgan, National Wildlife Federation, Washington, D. C., 1978.