Many species live their entire lives in wetlands and are completely dependent on them for survival. Other species are dependent on wetlands only during a portion of their life cycle. For these species wetlands serve either as a summer home, a winter home, or an occasional feeding or resting spot. Wetlands provide critical habitat for wildlife, and, in fact, wetlands exceed all other land types in wildlife productivity. It has been estimated that in the United States roughly 150 species of birds and more than 200 species of fish depend on wetlands for their survival.
Ducks occupy wetlands in great numbers.
Duck species include the wood duck, mallards, black ducks, blue-winged teal, gadwall, widgeon, and the northern pintail. Mammals such as the muskrat, beaver, raccoon, and white-tailed deer also use wetlands. In addition, a wide variety of reptiles, turtles, and freshwater fish depend on wetlands for survival. One group of animals often overlooked when the inhabitants of wetlands are considered is the invertebrate species. These small animals, which include flatworms, aquatic earthworms, leeches, crawfish, and fairy shrimp, are vital links between plants and the animal food chains.