—Scott Stephens, Ph.D.
A drake pintail stands guard while its mate dabbles away to capture the abundant fairy shrimp in a shallow depression filled with snowmelt. The drake alerts the hen, and they flush as a young bison calf romps up to the wetland for a drink with its much larger mother close behind. As the pintails rise above the prairie, they see an endless expanse of unbroken grassland dotted with hundreds of gleaming wetlands.
For millennia, this was a scene that greeted breeding ducks as they returned to the Prairie Pothole Region (PPR) in spring. Sculpted by the massive forces of glaciation, this 300,000-square-mile area, named for millions of shallow "pothole" wetlands of varying sizes and depths, was once among the most expansive wetland systems in North America. Surrounding these wetlands were vast prairie grasslands subject to frequent disturbance by wildfires and great herds of grazing bison. Along the northern and eastern boundaries of the prairies and boreal forest, aspen parkland dominated the landscape. The combination of diverse and productive wetlands and abundant upland cover constituted the most productive ecosystem for breeding waterfowl on Earth. When snowmelt and spring rains filled prairie wetlands across this region, duck production was spectacular beyond belief, and the resulting fall waterfowl migrations blackened the sky. This remarkable productivity for breeding waterfowl gave rise to the region's nickname, "the Duck Factory."
Today, waterfowl find a much different ecosystem when they return to the prairies. Gone are free-roaming herds of bison, and in many areas seasonal wetlands have been drained and grasslands plowed under. As homesteaders settled the prairies, they soon discovered that the rich soil that once supported lush grassland, bison, and ducks could also raise bumper crops of grain. Extensive waterfowl habitat loss ensued across the Duck Factory, especially in eastern portions of the region where rich soils and a relatively wet climate are especially conducive for growing row crops. In Iowa and Minnesota, which at one time may have contained the most productive waterfowl breeding habitat on the prairies, more than 95 percent of historic wetlands and grasslands have been converted to other uses.
Fortunately for waterfowl and hunters, significant expanses of wetland-rich grasslands remain intact in parts of the Duck Factory. Landscapes with steep terrain and less fertile soils are not as intensively farmed because of the barriers to cultivation these factors present. Additionally, large blocks of native grassland managed for cattle grazing remain on the western prairies where a more arid climate produces less consistent crop yields.
Perhaps the most productive geographic area left for breeding waterfowl on the prairies is the Missouri Coteau, a narrow band of rolling hills that runs from southern South Dakota to southern Saskatchewan. Until recently, the coteau's rugged topography and light, rocky soils generally discouraged cultivation, leaving large tracts of native prairie surrounding mosaics of potholes. In especially wetland-rich areas of this region, breeding duck densities can exceed 120 pairs per square mile. For breeding ducks, the coteau and similar landscapes are bastions of high-quality habitat. For waterfowl hunters, these landscapes are vital to sustaining duck populations now and in the future.
Secrets to Success
Over the past 15 years, Ducks Unlimited has conducted extensive research to better understand the needs of breeding waterfowl on the prairies. Based on this work, DU has gained a wealth of valuable information on the landscape and habitat conditions that influence duck breeding pair densities and nesting success across the region. Among the most important landscape features required for duck production is a functioning wetland community. Without wetlands to attract and provide food resources for breeding hens, ducks won't even attempt to breed. Land use practices on uplands surrounding wetlands also have a significant impact on wetland integrity and function. The healthiest wetlands on the prairies are usually found amid large blocks of native grassland, which are typically managed for livestock grazing. Ranchers view wetlands as valuable assets because they provide water for cattle and a much needed source of high-quality forage and hay during dry times.
In contrast, on cultivated landscapes many landowners view wetlands as a liability. Because crops don't fare well in saturated soils, farmers are often motivated to drain shallow seasonal wetlands embedded in cropland. Even on landscapes where wetland basins remain intact, soil erosion from surrounding fields can significantly degrade wetland productivity. Research on invertebrate communities in prairie wetlands has found that only a few millimeters of sediment can suffocate many species of aquatic insects that provide essential food resources for nesting hens. Additionally, runoff from herbicides and pesticides can harm wetland plants and decrease aquatic insect populations.
Beyond these impacts, upland land use can also affect how successful breeding ducks are in hatching nests and raising broods. Recent research on nesting success on the prairies has confirmed that the amount of grassland surrounding wetlands is an important factor influencing duck nesting success. Significant variability exists from year to year, but breeding ducks generally have better nesting success on landscapes with extensive perennial grass cover than on more intensively cultivated landscapes. Interestingly, studies suggest this relationship may not hold true in the parklands where nesting hens appear to fare better in native aspen habitat than in grassland. The parklands have a diverse predator community including numerous avian species such as hawks, owls, and corvids (crows and magpies), and the overhead cover provided by stands of aspen trees may provide the best protection for nesting hens in this environment
The Vanishing Prairie
Unfortunately, vital waterfowl habitat is now being lost at a staggering rate across the prairies, even in rugged areas like the Missouri Coteau. Surging global demand for food and ethanol is encouraging cultivation of every available acre. In the U.S. portion of the Duck Factory, declining enrollment in the Conservation Reserve Program (CRP), a Farm Bill program that pays farmers to restore grassland on marginal cropland under 10- or 15-year contracts, has resulted in a significant loss of upland nesting cover in many areas. During the past three years alone, more than 1.9 million acres of former CRP land have expired, and most of this upland cover has been converted back to cropland. Another 2.8 million acres of CRP could be lost in the next three years as more contracts expire. Even worse for the future of waterfowl, however, is the ongoing loss of native prairie, which represents the most abundant nesting habitat for waterfowl in the Prairie Pothole Region. Sadly, North Dakota, South Dakota, and Montana have lost more than 60,000 acres of native prairie each year since 2002. If current loss trends continue, maintaining recent duck population levels may be impossible.
Prairie wetlands are also at grave risk. In the United States, recent Supreme Court rulings have eliminated Clean Water Act protections for geographically isolated wetlands, leaving millions of small prairie potholes vulnerable to conversion. Presently, the Swampbuster provision of the Farm Bill, which prevents landowners who drain wetlands from receiving agricultural subsidies, is the last line of defense against wholesale wetland loss on the U.S. prairies and in many other regions. Wetland loss also remains the greatest threat to waterfowl in Prairie Canada, where few disincentives for wetland drainage are in place. And new threats such as wind power development could have unforeseen impacts on prairie waterfowl (see sidebar).
The stakes for waterfowl hunters couldn't be higher. About half of the average total annual production of ducks comes from the prairies. In addition, the U.S. Fish and Wildlife Service (USFWS) bases waterfowl season lengths and daily bag limits largely on the population status of breeding mallards and the number of ponds surveyed in Prairie Canada. As a result, reductions in midcontinent mallard populations of even 25 percent could result in shorter seasons and smaller daily bag limits in the Mississippi and Central flyways.
Going to the Source
Armed with an understanding of the key landscape features that influence duck nesting success, DU has developed conservation strategies specifically designed to address the birds' habitat needs. Clearly, protecting landscapes with high densities of intact wetlands surrounded by large tracts of perennial grassland or native aspen parkland is a top priority. Using wetland and waterfowl survey data collected by the USFWS and Canadian Wildlife Service along with cutting-edge land cover mapping technology, DU and key conservation partners like the USFWS have identified the most productive landscapes for breeding waterfowl across the Duck Factory. DU has also located tracts of remaining native prairie that are at particularly high risk of conversion to cropland. This information helps DU carefully target its conservation work in the most important places and ensures that every dollar contributed to DU provides the greatest return on the investment.
Perpetual conservation easements are a powerful tool used by DU, the USFWS, and other North American Waterfowl Management Plan partners to protect vital prairie habitats. Under these agreements, willing landowners donate or sell the right to cultivate their land, drain wetlands, and cut hay before the end of the waterfowl nesting season but retain all other rights on their property including the ability to raise livestock. The Missouri Coteau is one of the primary focus areas where DU and partners are working with landowners to protect vital waterfowl habitat. Hundreds of ranchers throughout Saskatchewan, North Dakota, and South Dakota have welcomed the opportunity to protect grasslands and wetlands on their property while maintaining their lifestyle and livelihood. Unfortunately, landowner demand for purchased easements currently exceeds available funding, but DU is dedicated to closing the funding gap and protecting this vital waterfowl habitat forever (see sidebar).
Supporting public policies that restore wetlands and grasslands is also an essential part of DU's conservation strategy on the prairies. In the United States, removing incentives for native prairie conversion (called Sodsaver in the last Farm Bill debate), increasing CRP acres in the U.S. Prairie Pothole Region, and maintaining Swampbuster protections for wetlands in the Farm Bill are top priorities. In addition, restoring Clean Water Act protections for prairie potholes and other geographically isolated wetlands will be vital to sustaining waterfowl populations at levels that can support recent hunting regulations.
On prairie landscapes where perennial upland cover is limited, protecting wetlands with perpetual easements that prohibit drainage will help secure a large waterfowl habitat base for the future that hopefully includes extensive grasslands. DU is also working to expand winter wheat cultivation on the prairies, which holds great promise for increasing upland nesting cover on intensively farmed landscapes. (For more information, see "Winter Wheat: the Duck-Friendly Crop.")
Despite all the changes that have occurred in the Duck Factory, enough prairie waterfowl habitat still exists to yield fall duck populations similar to those of the 1950s and 1970s. Perhaps the most important question for us to address today is how much more habitat can be lost before duck population peaks will be permanently reduced? Regardless of the challenges, there is no place where achieving conservation success is more important to the health of North America's duck populations. And rest assured that DU will be actively engaged in the policy, science, and on-the-ground habitat work necessary to keep the skies filled with waterfowl raised on the prairies.
Prairie Conservation Supporters
Ducks Unlimited is proud to acknowledge the philanthropy and financial support of the following Major Sponsors and federal and state partners who have made a commitment of at least $100,000 in cash or other donations to either Grasslands for Tomorrow or the Rescue the Duck Factory initiative:
Richard C. Adkerson
John and Shirley Berry
The Bush Foundation
John W. Childs
The James M. Cox Foundation of GA Inc.
Raymond T. Dalio
Bill and Sarah D'Alonzo
M. Austin Davis Foundation
Paul and Beverly Dickson
Skipper and Cindy Dickson
Dave and Marg Grohne
David F. and Margaret T. Grohne Family Foundation
Elmer and Irene Grohne Memorial
Independence Tube Corporation
Lee Ann and Orrin H. Ingram II
Jim and Sarah Kennedy
The Seymour H. Knox Foundation Inc.
Bruce R. Lauritzen
MDU Resources Foundation
Richard King Mellon Foundation
National Fish and Wildlife Foundation
National Shooting Sports Foundation Inc.
North American Wetlands Conservation Council
North Dakota Natural Resources Trust
William and Alice Oehmig
Saf and Betty Peacock
Irene W. and C.B. Pennington Foundation
Mark and Rebecca Pine Family
Cookie and T.R.* Potter Jr.
Dan and Linda Ray
Remington Outdoor Foundation
Richard and April Rice
The Spray Foundation Inc.
Mark and Lucy Stitzer
The Tucker Foundation
Turner Foundation Inc.
U.S. Fish and Wildlife Service
Wal-Mart Acres for America
Susan and Dr. James Walton III
Waterfowl Research Foundation Inc.
Hope and David Welles Jr.