By Johann Walker
Ducks Unlimited is dedicated to the vision of wetlands sufficient to fill the skies with waterfowl today, tomorrow, and forever. This vision drives the work of DU's conservation staff across the continent. And while the goal never changes, DU's conservation work is constantly evolving in response to new scientific information and the changing needs of waterfowl populations on diverse landscapes across the continent.
Scientific research and monitoring have always provided the objective foundation for DU's waterfowl conservation efforts. Waterfowl ecologists and managers have long recognized that to effectively sustain waterfowl populations, they need to understand relationships between population dynamics and habitat. For example, one of DU's highest priority conservation areas is the Prairie Pothole Region (PPR) of the United States and Canada. Several waterfowl species including mallards, pintails, gadwalls, and blue-winged teal reach their highest breeding densities in this wetland-rich region, and more than half of the continental fall flight can be produced in the PPR in some years. But habitat quality and waterfowl breeding success are highly variable within the PPR. The presence of a large number of breeding waterfowl pairs in a particular area doesn't necessarily guarantee those pairs will produce a large number of ducklings.
To maximize the efficiency of its conservation work, DU must identify and conserve the landscapes where waterfowl are most productive. Analysis has shown that three factors influence mallard populations more than anything else: nest success, survival of breeding hens, and survival of ducklings. Extensive DU research has shown that nest success is consistently higher on landscapes with more permanent grass cover than on more intensively farmed landscapes. And because most hen mortality occurs while the birds are nesting, survival of breeding hens is higher on grassland-dominated landscapes as well. DU research has also found that duckling survival is highest on landscapes with ample shallow wetland habitat during the brood-rearing period. Thus, DU has identified that the most productive landscapes for breeding waterfowl in the PPR are those with a combination of numerous shallow wetlands (to support breeding pairs and broods) and extensive grassland (to provide cover for hens and their nests).
Once the most productive landscapes for breeding waterfowl have been identified, it's vital to understand how land use is likely to affect these landscapes in the future. Changing demand for agricultural commodities is a driving force behind landscape change in the PPR. When demand for commodities increases, shallow wetlands are filled and drained, native grasslands are plowed under, and restored grasslands on marginal soils are returned to production. Then, as commodity production meets and exceeds demand, restoration of grasslands and wetlands increases. Waterfowl habitat can rarely be restored to its original productivity, however, after landscapes have been altered.
Using waterfowl survey data and landscape mapping tools, DU has identified certain landscape characteristics in the PPR where grasslands and wetlands are at greatest risk of conversion to cropland. Flatter, more fertile grasslands on landscapes with greater amounts of existing cropland tend to be at greater risk of conversion to cropland. Wetlands embedded in existing crop fields are more likely to be drained than wetlands in pastures or restored grasslands. These landscape characteristics have allowed DU to identify the productive habitat that is at greatest risk of loss.
Another consideration for waterfowl conservationists is the cost of protecting habitat. DU and its partners simply don't have the funding to protect every acre of good waterfowl habitat in the short term. Consequently, knowing the "going rate" for habitat protection (either by purchasing grassland easements or through direct acquisition) is required to identify conservation "bargains" where highly productive habitat that is at high risk of loss can be protected for a relatively low price.
Science also provides the foundation for DU's public policy work in support of prairie waterfowl habitat conservation. Ducks Unlimited shares a wealth of scientific data with policymakers and other conservation partners about wetland and waterfowl ecology; the economic benefits of conservation policies; and the demographics, attitudes, and behavior of sportsmen and other constituencies. DU uses this information to encourage policymakers in state, federal, and provincial governments to adopt policies that protect and restore key wetlands and grasslands on the prairies. For example, DU has been a leader in supporting appropriations and reauthorization for the North American Wetlands Conservation Act, which has generated millions of dollars for waterfowl habitat conservation on the prairies and across the continent.
Maintaining a sufficient habitat base to support abundant waterfowl populations is a challenging proposition. Scientific information makes it possible for conservation planners to develop effective and efficient conservation programs and also to influence important public policies. Integrated information about productivity of breeding ducks, risk of habitat loss, and cost of protecting habitat provides the foundation for habitat conservation efforts that will continue to ensure that whenever water comes to the prairies, the skies will be filled with ducks.
Johann Walker is manager of conservation programs at DU's Great Plains office in Bismarck, North Dakota.