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The major types of wetlands include bogs, fens, marshes, and swamps. Bogs and fens are most common in cold climates and are characterized by extensive deposits of partially decayed plant material called peat. Bogs have highly acidic soils. The soils of fens are not highly acidic. Mosses are abundant in both bogs and fens. Marshes and swamps usually lack peat deposits and occur in both warm and cold climates. Marshes are found in the shallow waters of lakes and streams. Cattails, horsetails, bulrushes, and other nonwoody plants are common in marshes. Swamps tend to develop in areas that are not permanently flooded. Trees and shrubs are the most prominent plants in swamps. Coastal wetlands, such as salt marshes and tropical mangrove swamps, are exposed to a mixture of fresh water and salt water. Many kinds of animals inhabit wetlands. They include a wide variety
of birds and insects; amphibians, such as frogs and salamanders;
and such reptiles as alligators, snakes, and turtles. Many mammals, including beavers, muskrats, and otters, also live in wetlands. Wetlands play an important role in nature. In addition to being a habitat for many plants and animals--particularly many endangered species--wetlands help to control flooding because they retain large amounts of water. The water stored by wetlands also serves as a source of replenishment for ground water supplies. In addition, people use wetlands for fishing, hunting, and nature study. Many wetlands throughout the world have been destroyed by human
activities. Almost half the wetlands in existence at the time the
United States was first settled have been destroyed. Since the early
1970's, however, awareness of the ecological and economic value
of wetlands has steadily increased. In the United States, various
federal and state programs have been designed to preserve the remaining
wetlands. But a significant number of wetlands continue to be destroyed.
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