What’s a wetland anyway, and why are they so important to protect?

Among the most important ecosystems on Earth, the wet ecosystems of bogs, freshwater marshes, prairie potholes, forested swamps, and salt-water estuaries provide critical nesting, rearing, feeding, and stop-over habitat for bird and other wildlife populations in watersheds across the nation. Wetlands are essential to estuary, river, and watershed health, trapping sediments and cleaning polluted waters, preventing floods, recharging groundwater aquifers, and protecting shorelines. Wetland health is intimately tied to human health.

Wetlands began disappearing soon after permanent European colonization of the United States. More than half of the 215 million acres of wetlands that existed at the time of settlement have been destroyed. Only 100 million acres remain today. Throughout much of our nation’s history, wetlands were viewed as obstacles to development that should be eliminated. Federal laws provided incentives for draining and destroying wetlands. Only in the last twenty-five years have public and government understanding of the importance of wetlands grown enough to begin to change some incentives to protecting and restoring wetlands.

Still, despite their now well-understood importance to ecosystem health, wildlife, families and communities, wetlands continue to be destroyed at an alarming rate, over 100,000 acres per year in watersheds across the country. As wetlands are destroyed, so too are vital natural habitats for many species of songbirds, frogs, fish and other birds and wildlife. As these species and their insect-based food chain disappear, whole ecosystems are disrupted. These changes impoverish our lives and our children’s future.

What’s a wetland, anyway?

"Wetland" is a generic term for all the different kinds of wet habitats where the land is wet for some period of time each year but not necessarily permanently wet. Many wetlands occur in areas where surface water collects or where underground water discharges to the surface, making the area wet for extended periods of time. Other wetlands occur along our coasts, such as salt marshes, and are created by the tide. The federal Clean Water Act defines wetlands as "areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas."

Some common wetlands you might recognize include:

Salt marshes occur along our coasts near river mouths, on broad coastal plains, and around protected lagoons. They are biologically rich ecosystems, consisting of salt-tolerant grasses and water levels that fluctuate with the tide. Nearly 80 percent of the nation’s salt marshes are found with estuaries such as Chesapeake Bay, San Francisco Bay, and Long Island Sound.

Coastal fresh marshes are located directly inland from salt marshes where the movement of water is influenced by tides, and salinity levels are low. Many species of fish spend all or part of their life cycles in fresh marshes. Salmon and other types of anadromous fish use coastal fresh marshes as nurseries or spawning grounds. Numerous bird species and small furbearing mammals feed, nest, and find shelter in these marshes.

Swamps, unlike marshes, are dominated by woody shrubs and trees, some with hardwoods such as red maple and ashes and others with softwoods like cedar and spruce. In hardwood swamps, a variety of shrubs and plants, such as skunk cabbage, grow beneath the forest canopy. Shrub swamps are dominated by willows, alders, shrubby dogwoods, and buttonbush. Some shrub swamps are permanent, while others slowly transform themselves into true forested swamps.

Bogs are peatlands, usually lacking an overlying layer of mineral soils. They occur primarily in formerly glaciated of the Northeastern U.S., the north-central states, and Canada and often develop in deep glacial lakes. The peat is formed by the gradual decomposition of plants, especially in highly acidic soils and poorly drained areas. The peat forms a floating mat of vegetation over water that may accumulate up to forty feet. Bogs are characterized by evergreen trees and shrubs and are often covered by sphagnum moss.

Vernal pools are, literally, spring pools that tend to fill up in spring and dry up in summer. The important point is that biological activity peaks in spring. In general, vernal pools are small, temporary, and "isolated" from other wetlands, streams, or other water bodies. They provide essential breeding habitat for certain animals, such as fairy shrimp and some species of amphibians. While not all vernal pools dry up completely, the essential ingredient is that the pond has no fish.

Forested floodplain wetlands develop along larger rivers. In the Southeastern U.S. and along the Gulf of Mexico, extensive bottomland hardwood swamp forests occur alongside slow-moving rivers. Here tupelos, baldcypress, sweetgum and red maple are regularly flooded by the river.

Pocosins are boggy shrub wetlands that occur along the coastal plain from Virginia southward to South Carolina. Pocosins are covered with evergreen hollies and bays, and scattered stands of pond pine.

Prairie potholes are shallow depressions scattered across the upper Midwest and the Dakotas that were carved out by retreating glaciers some 10,000 years ago. These wetlands provide crucial habitat for more than 100 species of birds and support the greatest variety and number of animals of any biological community on the continent.

More types and names for wetlands:

Inland saline and alkaline marshes and riparian wetlands of the arid and semiarid west and Great Plains

Tundra wetlands of Alaska

Muskeg

Tideflat

Pond

Cienega

Wet pine flatwoods

Willow Carrs

Alpine meadow wetlands of the west

Playa lakes of the southwest and Great Plains

Wet meadows or wet prairies of the Midwest

Mangrove swamps of the southern coast

Sea grass meadows in estuaries

River deltas at the mouths of estuaries

Here are some of the most important reasons to save our remaining wetlands:

Habitat for birds and other wildlife. Up to one-half of North American bird species nest, feed, or rest in wetlands. As our wetlands have been destroyed, bird populations have slowly declined. In the last fifteen years alone, for example, the continental duck breeding population fell from 45 million to 31 million birds, a decline of 31 percent. Between 1978 and 1987, seventy-five percent of forest-dwelling neotropical migrants, many of which rely on coastal wetland habitats during their arduous migrations, declined in numbers. The number of birds migrating over the Gulf of Mexico, which rely on coastal wetlands as staging areas in Louisiana and Mississippi especially, has decreased by one-half since the mid-1960’s.

Nearly half of all federally threatened and endangered species rely on wetlands. A majority of fish and many species of amphibians, insects and plants are wetland dependent. In dry climates, the value of wetlands to birds and other wildlife is magnified. For example, in the Rocky Mountains, wetlands occupy only one percent of the landscape but support 81 percent of the area’s migratory bird populations.

Clean water. Wetlands are vital to cleansing the nation’s water, trapping sediment and capturing nutrients from waters that flow through them. Wetlands save communities millions every year that otherwise would be spent on drinking water treatment plants. For example, if the wetlands of the Congaree bottomland hardwood swamp in south Carolina were destroyed, the cost to the community to install a water treatment plant would be $5 million.

Flood prevention. By soaking up and storing storm water, wetlands help prevent flooding, and this saves families and communities from tragedy and great expense. In a 1983 study, the U.S. Army Corps of Engineers found that protecting wetlands along the Charles river near Boston resulted in annual savings of $17 million in flood damage prevented.

Fisheries and jobs. Fishing is big business and is the economic engine for many communities. All species of freshwater fish depend on wetlands either directly for food, habitat or breeding or indirectly by consuming prey that are wetland dependent. Seventy-five percent of all commercial marine fish and shellfish depend on wetlands. Sport and commercial fishing pumps about $152 billion annually into local communities, providing two million jobs.

Tourism. In 1991, more than 24 million Americans reported they traveled to watch birds. Bird watching and hunting now generate over $19 billion and 220,000 jobs annually. In 1985, five birding festivals were held in the U.S., and 1997 more than 60. In Grand Island, Nebraska, the annual Sand Hill Crane festival brings in tourists who give a $40 million boost to the economy.

Action Alerts | Mission | National Map | Results | Join Wetland Campaign | Local Chapter Input
Birds | Wetland Ecosystems | Join Activist Network | Funding | Resources | Links | People

email us: wetlands@audubon.org

Webweaver: planman Last Update: 1.5.99