For decades, many thought wetlands were mucky, mosquito-infested places and drained them to use as farmland, industrial sites, or residential areas. Fewer than half as many acres of wetlands remain in the continental United States compared with when the first European settlers arrived about 500 years ago. Now, wetlands are recognized as important wildlife refuges and water purification systems. Wetlands are areas that have standing water for at least part of the year. Marshes, swamps, tidal flats and associated pools, bayous, and bogs are the most common.
Marshes are water-saturated, poorly drained areas with both aquatic and grasslike plants.
Swamps, unlike marshes, have trees and bushes. Water flows into swamps and marshes from streams, or even an ocean. Bogs are waterlogged, spongy ground in former lakes now filled with living and dead mosses, which eventually become peat. Wetlands are important for many reasons. They support a large volume of plants, which in turn supply cover and food for animals.