Percentage of Wetlands

Acreage Lost, 1780s–1980s

Destroying or

degrading

wetlands can

lead to serious

consequences,

such as

increased

flooding,

extinction of

species, and

decline in water

quality. We can

avoid these

consequences

by maintaining

the valuable

wetlands we

still have and

restoring lost or

impaired

wetlands where

possible.

United States Office of Water EPA 843-F-01-002d

Environmental Protection Office of Wetlands, September 2001

Agency Oceans and Watersheds (4502T)

What Is the Status of Our Nation’s Wetlands?

More than 220 million acres of wetlands are thought to

have existed in the lower 48 states in the 1600s. Since

then extensive losses have occurred, and more than

half of our original wetlands have been drained and

converted to other uses. The mid-1950s to the mid1970s were a time of major national wetland loss.

Since then the rate of loss has slowed.

The National Audubon Society notes that

bird populations continue to decrease as

wetlands are destroyed. In the past 15 years

alone, the continental duck breeding population fell from 45 million to 31 million birds,

a decline of 31 percent. The number of birds

migrating over the Gulf of Mexico, which

rely on coastal wetlands as staging areas

(especially in Louisiana and Mississippi), has

decreased by one-half since the mid-1960s.

Approximately 100 million wetland acres

remain in the 48 contiguous states, but they

continue to be lost

at a rate of about

60,000 acres

annually. Draining

wetlands for

agricultural

purposes is

significant, but

declining, while

development

pressure is

emerging as the

largest cause of

wetland loss.

Unfortunately, many remaining wetlands are

in poor condition and many created wetlands

fail to replace the diverse plant and animal

communities of those destroyed.

When a wetland functions properly, it

provides water quality protection, fish and

wildlife habitat, natural floodwater storage,

and reduction in the erosive potential of

surface water. A degraded wetland is less able

to effectively perform these functions. For

this reason, wetland degradation is as big a

problem as outright wetland loss, though

often more difficult to identify and quantify.

What Is Adversely Affecting Our

Wetlands?

Human activities cause wetland degradation

and loss by changing water quality, quantity,

and flow rates; increasing pollutant inputs; and

changing species composition as a result of

disturbance and the introduction of nonnative

species. Common human activities that cause

degradation include the following:

Hydrologic Alterations. A wetland’s characteristics evolve when hydrologic conditions cause

the water table to saturate or inundate the soil for

a certain amount of time each year. Any change

in hydrology can significantly alter the soil chemistry and plant and animal communities. Common

hydrologic alterations in wetland areas include:

! Deposition of fill material for development.

! Drainage for development, farming, and

mosquito control.

! Dredging and stream channelization for

navigation, development, and flood control.

! Diking and damming to form ponds and

lakes.

! Diversion of flow to or from wetlands.

! Addition of impervious surfaces in the

watershed, thereby increasing water and

pollutant runoff into wetlands.

Pollution Inputs. Although wetlands are capable

of absorbing pollutants from the surface water,

there is a limit to their capacity to do so. The

primary pollutants causing wet-land degradation

are sediment, fertilizer, human sewage, animal

waste, road salts, pesticides, heavy metals, and

Twenty-two states have lost at

least 50 percent of their

original wetlands. Since the

1970s, the most extensive

losses have been in Louisiana,

Mississippi, Arkansas, Florida,

South Carolina, and North

Carolina.

Source: Wetlands,

2nd edition,

Van Nostrand and

Reinholdt, 1993.
selenium. Pollutants can originate from many

sources, including:

! Runoff from urban, agricultural,

silvicultural, and mining areas.

! Air pollution from cars, factories, and

power plants.

! Old landfills and dumps that leak toxic

substances.

! Marinas, where boats increase turbidity and

release pollutants.

Vegetation Damage. Wetland plants are

susceptible to degradation if subjected to

hydrological changes and pollution inputs.

Other activities that can impair wetland

vegetation include:

! Grazing by domestic animals.

! Introduction of nonnative plants that

compete with natives.

! Removal of vegetation for peat mining.

What Can You Do?

Nearly 75 percent of all wetlands are privately

owned, making it imperative that the public

participate in wetland management and

protection. Here are some things you can do:

! Conserve and restore wetlands on your

property.

! Support local wetlands and watershed

protection initiatives by donating

materials, time, or money.

! Work with your local municipalities and

state to develop laws and ordinances that

protect and restore wetlands.

! Purchase federal duck stamps from your

local post office to support wetland acquisition.

! Participate in the Clean Water Act Section 404

program and state regulatory programs

by reviewing public notices and

commenting on applications.

! Encourage neighbors and developers

to protect the function and value of

wetlands in your watershed.

! Avoid wetland alteration or

degradation during project construction.

! Maintain wetlands and adjacent buffer

strips as open space.

! Reduce the amount of fertilizers,

herbicides, and pesticides applied to

lawns and gardens.

A Global Overview of Wetland Loss and Degradation. Available on The Ramsar Convention on Wetlands’ web site at

www.ramsar.org/about_wetland_loss.htm.

Wetland Issues. Available on-line at www.ncseonline.org/NLE/CRSreports/Wetlands/wet-5.cfm.

Wetlands Loss and Degradation. Visit the North Carolina State University Water Quality Group’s on-line informational

database, WATERSHEDSS, at h2osparc.wq.ncsu.edu/info/wetlands/wetloss.html.

Wetlands and Agriculture: Private Interests and Public Benefits, Ralph E. Heimlich et al. USDA–ERS Report No. 765.

Available on-line at www.ers.usda.gov/publications/aer765.

Pollutants such as

sediment, nutrients,

pesticides, and heavy

metals degrade wetlands

and water quality across

the country.

The Wetland Fact Sheet Series

Wetlands Overview Funding Wetland Projects

Types of Wetlands Wetland Monitoring & Assessment

Functions & Values of Wetlands Sustainable Communities

Threats to Wetlands Volunteering for Wetlands

Wetland Restoration Teaching about Wetlands

For more information, visit www.epa.gov/owow/wetlands.

American Avocet

Swamp tupelo