The Power of Wetlands
Acre for acre, wetlands benefit people and wildlife more than any other ecosystem
By Steve Adair, PhD
Wetlands are among the most productive ecosystems on earth, providing environmental benefits comparable to the iconic Amazon rain forests. These dynamic natural systems serve as transition zones between land and deeper water and often experience periodic wet and dry cycles in response to variable precipitation and water levels. When water fills wetlands that have previously been dry, the algae, plants, and invertebrates that make up the food chain explode, supporting an incredible abundance and diversity of wildlife. When wetlands go dry, nutrients stored in plant matter decompose, aquatic insects go dormant, and emergent vegetation flourishes, setting the stage for future booms in productivity when water returns.
Waterfowl and other migratory birds are among the most visible products of these vital habitats. However, wader-clad scientists equipped with test tubes, microscopes, and flow meters have documented many other benefits that wetlands provide for people. These "ecosystem services" include removing excess nutrients and harmful chemicals from surface water runoff, recharging aquifers used for irrigation and drinking water, and protecting communities from flooding and coastal storm surges. Let's take a closer look at these wetland benefits and some of the ways that Ducks Unlimited and Wetlands America Trust (WAT) serve our communities by conserving these multipurpose habitats.
Whether the refreshing glass of water you enjoy on a hot summer day comes from the tap or from a bottle, it's highly likely that wetlands helped make that water suitable for drinking. Scientists refer to wetlands as nature's kidneys because they filter and purify water as it passes through them. Wetland plants and soils are especially effective at removing nitrates from runoff water before it enters rivers and streams. High levels of nitrates in water cause human health problems and contribute to hypoxia (low oxygen levels) in waterways, which can create "dead zones" along our coastlines.
A recent study by scientists at the University of Minnesota found that wetlands are five times more efficient at reducing nitrates in runoff water than are other natural systems. DU is working with Nestlé Purina PetCare, Microsoft Corporation, Wells Fargo Foundation, USDA Natural Resources Conservation Service, Iowa Department of Natural Resources, Iowa Department of Agriculture and Land Stewardship, and Iowa State University to create and monitor wetlands in the ecologically important Prairie Pothole Region of the northern United States and Canada. These wetlands are designed specifically to remove nitrates from cropland runoff and improve water quality. Tremendous potential exists for DU and WAT to replicate and expand these efforts in other areas to improve water quality for people and provide wetland habitat for waterfowl and other wildlife.
Wetlands not only help purify surface water but also replenish underlying aquifers. On the southern Great Plains, the Ogallala Aquifer is a vital water source for agriculture, homes, and communities in eight states. In some areas, the aquifer discharges water directly into rivers such as the Platte and Arkansas. In others, the aquifer is recharged from the surface by ephemeral wetlands known as playa lakes. Recent research shows that water provided by playa wetlands adds three inches to the level of the Ogallala Aquifer each year.
By protecting and restoring wetlands on the southern Great Plains, DU and its partners in the Playa Lakes Joint Venture are helping recharge the Ogallala Aquifer and provide vital habitat for waterfowl and other migratory birds. In Colorado, for example, DU and WAT work with private landowners and other partners to establish "recharge wetlands" along the historic Platte River. Water is diverted into these wetland basins during times of excess river flow. The water then gradually seeps back into the river, recharging the aquifer in the process. Water that returns to the river generates water credits for landowners, who can use the credits to offset water taken out of the river for irrigation and other uses. These wetland conservation efforts not only provide important migration and wintering habitat for waterfowl and other migratory birds but also increase the availability of water for farmers, municipalities, and recreational users along the Platte.
Another important societal benefit provided by wetlands is flood mitigation. Like giant sponges, wetlands trap runoff water in their basins, which decreases the speed and volume of water flowing downstream. The frequency of flooding events along the Mississippi and Missouri Rivers has increased in recent years as these rivers have been cut off from their floodplains, dramatically reducing the natural flood-storage capacity in their watersheds. According to a recent report, 90 percent of the Mississippi River's original floodplain in some areas is now disconnected from its source. To protect communities from flooding and maintain fish and wildlife habitat, DU is working to protect and restore floodplain wetlands in high-priority areas across the United States.
One place where DU has been especially active in conserving these important wetlands is in the "Confluence Floodplain," where the mighty Mississippi and Missouri Rivers meet just north of Saint Louis, Missouri. Here, WAT has worked with private landowners to keep floodplain wetlands in place and functioning through conservation easements. As part of the Missouri Agricultural Wetlands Initiative, DU is working with numerous partners to establish and restore wetlands across the floodplain. In addition, DU is an active member of the Missouri/Mississippi Rivers Confluence Conservation Partnership, led by the US Fish and Wildlife Service and Great Rivers Habitat Alliance. This partnership is supported by a broad coalition of private landowners, farmers, local businesses, state and federal agencies, and nonprofit organizations, which all share the common goal of conserving the area's wildlife habitat values while also protecting Saint Louis and other downstream communities from catastrophic flooding.
Coastal Storm Protection
For people who live along the nation's coasts, wetlands serve as an important line of defense against storms. Dense vegetation in coastal wetlands helps protect communities by dissipating wind and wave energy as storms come ashore. A recent study on the Gulf Coast found wetlands to be among the most cost-effective forms of storm protection for communities. Wetlands can recover naturally from storm impacts, unlike hard infrastructure such as levees and sea walls that require costly repairs and regular maintenance.
Ducks Unlimited is partnering with the Texas General Land Office, The Meadows Foundation, US Fish and Wildlife Service, NOAA–National Marine Fisheries Service, Texas Parks and Wildlife Department, and many others to construct over 14 miles of breakwaters to buffer wetlands from erosion at three popular wildlife areas and other locations along the Texas coast. These practices maintain wetland habitats, improve water quality, and help protect inland communities and infrastructure from the impacts of tropical storms.
Recreational and Commercial Fisheries
Located where freshwater carried by rivers and streams mixes with saltwater from the ocean, coastal wetlands and estuaries support a rich diversity of habitats that provide food and shelter for many species of fish and wildlife. Coastal wetlands and estuaries serve as nurseries for more than 68 percent of the nation's commercial fish catch and 80 percent of its recreational catch. These fisheries contribute billions of dollars to the US economy each year. Popular species that spend some or all their lives in coastal wetlands and estuaries include salmon, herring, spotted sea trout, redfish, striped bass, blue crabs, shrimp, and oysters.
Ducks Unlimited works along America's coastlines to restore marshes and estuaries to benefit waterfowl, other wildlife, and fisheries that depend on these vital ecosystems. Through a recent project in western Washington, DU partnered with Shell Oil Company, Skagit Fisheries Enhancement Group, and Skagit Conservation District to restore a small estuary and an adjacent native tree buffer. Restoration of this estuary will benefit a variety of migratory birds and provide productive nursery habitat for Chinook salmon, which are an important part of the marine food chain as well as the culture of the local native community. Healthy Chinook salmon populations are vital to the recovery of orcas, providing a key food source for those majestic marine mammals in Puget Sound. This project is a shining example of the multiple benefits of wetlands conservation.
Outdoor Recreation and Wellness
Throughout history, people have been drawn to wetlands. Cities such as Boston, San Francisco, Seattle, and Tampa Bay are located on estuaries, where nearby coastal wetlands are popular places for people to pursue many forms of outdoor recreation, including hunting, fishing, bird-watching, paddling, hiking, and photography. Forty-three percent of US adults visit an estuary at least once each year, generating $12 billion in annual revenue. For example, Don Edwards San Francisco Bay National Wildlife Refuge, the first urban refuge in the United States, hosts almost 900,000 visitors each year, giving Bay Area residents the opportunity to see firsthand the many benefits that wetlands provide to people and wildlife.
Outdoor recreation is not only important for our economy but also our health. Growing scientific evidence indicates that spending time outdoors improves wellness. Contact with nature positively impacts blood pressure, blood chemistry, stress levels, and happiness. When we are outdoors, we breathe cleaner air, we are more active, and our senses are heightened.
Clearly, wetlands benefit all of us. They clean and replenish our drinking water, they protect our communities from floods and storms, they give us food, and they provide places for us to enjoy the outdoors and be healthy. Ducks Unlimited and Wetlands America Trust are passionate about conserving these crucial habitats. We have been learning, adapting, and perfecting our wetlands conservation craft for more than 80 years. As more people become aware of the power of wetlands, we are certain that we will receive more support for our mission from broad segments of society, including corporations, foundations, and the general public. The potential to restore this continent's wetlands is truly unlimited, and we look forward to forming new partnerships to conserve these natural treasures together.
Dr. Steve Adair is DU's national director for conservation strategy. He is based in Bismarck, North Dakota.