Wetlands are home to 31 percent of plant species in the United States, according the the U.S. Environmental Protection Agency. Most American wetlands are one of four types: marshes, which have mostly soft-stemmed vegetation; swamps, with mostly woody plants; bogs, which have evergreens, peat deposits and a deep layer of sphagnum moss; and fens, with mostly grasses, reeds, wildflowers and sedges.
Part of the Food Web
Wetland plants are part of the food web in the wetland ecology. The U.S. Environmental Protection Agency refers to wetlands as "biological supermarkets," because they produce such great quantities of food for so many different species of animals. At the bottom of the the chain are the leaves and stems of dead wetlands plants, which break down into small organic particles which feed many small insects, shellfish and small fish. These in turn provide sustenance for larger predators, such as large fish, reptiles, amphibians, birds and mammals.
Wetland Plants Act as a Filter
When water comes in to a wetland, it is slowed as it moves around the plants. Sediment in the water, like deposits from municipal sewage plants, are often absorbed by plant roots, which serve as a filtration system. In fact, plants are so efficient at removing sediment, excess nutrients and other pollutants from waste water that municipalities sometimes construct artificial wetlands to treat storm water.
Flood and Erosion Protection
Wetlands provide a storage area for flood waters, and trees and other wetland vegetation slow the rush of floods and help distribute the water evenly over a flood plain. Wetland plants are also valuable along shores, where their roots hold the soil in place, helping to prevent erosion during storm surges.
Many industries are dependent on the plants which grow in wetlands. We often forget that some favorite foods, such as blueberries, cranberries and wild rice, are actually wetland plants. Some wetland plants, including wild rice and reeds, are harvested for use in cosmetics, decorative items and even medicine. Much of the nation's commercial fishing industry is dependent on wetlands and thus on wetland plants.
Part of a Global Cycle
Wetland plants are part of the global water, nitrogen and sulphur cycles. The Massachusetts Office of Coastal Zone Management points out that wetland plants store carbon instead of releasing carbon dioxide into the atmosphere, thus playing an important role in helping to keep our planet's air healthy. Scientists are beginning to believe that wetlands actually function as "atmospheric maintenance" for the planet.