by Scott Stephens, Ph.D.
As I bumped along a dusty gravel road in central South Dakota, I checked my map for the next red-outlined square. With the public radio station as my only companion, I was recording the location of remaining native grassland in this sparsely populated portion of the Missouri Coteau. As I approached the next tract of grassland, I noticed a dark plume of smoke rising from one corner of the section. Driving closer, I could see that the source of the smoke was a large four-wheel-drive tractor, and it was plowing under the native prairie.
Although I had spoken to groups and written many times about the recent increase in prairie loss across the Dakotas, I was not prepared for the visceral reaction I had while witnessing the destruction firsthand. Many thoughts and emotions surfaced as I watched the little bluestem and buffalo grass turned under to expose the gray dirt beneath. One thought I could not shake was that pintails returning here would find their ancestral nesting area gone. Thousands of generations of pintails had likely returned to this very patch of prairie to nest and raise their young since glaciers created these wetland-rich grasslands over 10,000 years ago.
The destruction of this irreplaceable ecosystem is tragic, and unfortunately, it is escalating. What I witnessed occurs each year across tens of thousands of acres in the Dakotas. Sadly, the loss of these prairie grasslands, and the wetlands within them, will be devastating to duck populations, sportsmen, and businesses related to waterfowling.
Ducks returning to prairie breeding areas each spring have certain basic requirements that must be met in order for them to produce young. Clearly, breeding ducks need quality wetlands. They provide the protein-rich aquatic insects that hens need to produce eggs and maintain themselves during nesting and brood rearing. Because this food resource is so important at this time of year, ducks will not tolerate breeding pairs of the same species on their wetland. Different species are able to coexist on the same shallow pothole only because they forage on slightly different foods.
Breeding ducks also need large expanses of grasslands. Miles of unbroken grassland increase the chances of nests hatching. Dabbling ducks like mallards, pintails, and teal nest in grass up to a mile from the nearest wetland. They will scrape out a small depression in the ground, carefully line it with nearby vegetation, and then add down feathers as they begin incubating the eggs. Nesting hens must select a location where they can lay 9 to 12 eggs and safely sit on the nest for 32 to 38 days. Because a clutch of protein-rich eggs lying on the ground is an easy target for hungry predators, conserving or restoring landscapes where predator impacts are minimized is essential to maintaining duck populations.
Areas dominated by grassland offer a couple of advantages for nesting ducks. Grassland-dominated landscapes tend to have predator communities made up of species such as coyotes and badgers, which have large home ranges and do not spend much time in any given field. These "big grass" landscapes offer large acreages that could potentially hold nests. As a result, when duck nests are spread out, predators must search larger areas and therefore are usually less effective in finding nests.
Because nest success is one of the most important factors influencing duck populations, Ducks Unlimited conducts research to understand the key habitat characteristics associated with nest success. Each spring, research crews on the breeding grounds of the United States and Canada locate duck nests and monitor their success across study sites with diverse habitat and landscape conditions. Some sites are dominated by cropland, and others are mostly grassland. With this approach, researchers can determine the characteristics of the habitat and landscapes where ducks achieve high nest success. This information helps DU identify the highest priority conservation targets.
Results from the past six years of research confirm some important factors affecting nest success. Ducks achieve the highest nest success rates on landscapes dominated by grassland with little adjoining cropland. Although sites with lower levels of grassland can sometimes yield high nest success, those dominated by grassland are usually the most consistent, long-term duck producers. But these grassland-dominated areas are the very ones being lost.
New threats for grasslands
Since the last glaciers retreated, North America's wetland-rich native prairies have provided nesting cover for thousands of generations of ducks. Although the U.S. portion of the Prairie Pothole Region (PPR) has lost more than 78 percent of its original grassland, nearly 23 million acres remain in the pothole country of Montana, North Dakota, and South Dakota, and native prairie is still the most abundant nesting cover in the region. But conversion of grassland to cropland has increased recently due, in part, to technological advances in agriculture. New, genetically modified versions of soybeans and other crops are more drought-tolerant and unaffected by herbicides. As a result, they may be grown in areas previously considered unsuitable for cropland. Innovations in farm equipment have also made it possible to till areas that previously would not have been candidates for cultivation.
Because of these new pressures, DU determined it was important to conduct research to understand the scale of the problem. With help from conservation partners such as The Nature Conservancy, U.S. Fish and Wildlife Service, the University of Montana, and South Dakota Game, Fish and Parks, DU began research in 2003 to examine loss of native grassland across the Missouri Coteau region of the Dakotas. The research has been used to develop planning tools that help predict which grasslands are at the greatest risk of being lost in the future.
To conduct this research, DU needed to know the status of individual native prairie tracts over time across a broad area of the Missouri Coteau. Fortunately, satellite imagery for this area existed as far back as 1984. These images provided a way to follow individual prairie tracts to determine whether they had been converted to cropland. Researchers monitored nearly 65,000 separate 40-acre tracts of native prairie during this project.
The research showed that the trends in prairie loss are not encouraging. Since 1984, the overall average rate of prairie grassland loss has been 0.5 percent per year. In some areas, where the highest rates of grassland loss are occurring, the rate approaches 2 percent a year. A 2 percent a year loss may not seem like much, but at that rate, half the remaining grassland will be lost in only 34 years. And, unfortunately, loss rates across the Missouri Coteau have been increasing since 2000.
The Farm Bill and CRP
Beyond advances in agriculture, grassland loss is also tied to economics, federal agricultural policy, and decisions made by individual landowners. The big driver seems to be unintended consequences of the last Farm Bill. The diversity of commodity supports has made cultivation of crops economically viable even in areas where soils are not high quality and environmental conditions are highly uncertain. Price supports and risk reduction programs such as disaster payments and crop insurance are crucial to a sustainable agriculture industry in the United States, but these safety nets were not established to facilitate conversion of additional acres of grassland to cropland in drought-prone areas.
Conversion of native prairie to cropland is only one of the threats to grasslands in the PPR. The Conservation Reserve Program (CRP), initiated with the 1985 Farm Bill, has been one of the most heralded agricultural programs ever because of its benefits to wildlife. CRP converts marginal cropland to grassland under 10– or 15–year contracts. This program has greatly benefited the plains of Montana, North Dakota, and South Dakota, as well as the wildlife species that depend on grassland habitat. Millions of acres of restored grassland have changed the landscapes of the PPR, and ducks and other wildlife have responded positively. But changes to the CRP program make the future of these productive grasslands uncertain.
In 2007 alone, contracts will expire on 2.8 million acres of restored CRP grassland in the Dakotas and Montana. Options for re-enrollments have been offered on only 1.2 million of those expiring acres. The remaining acreage will receive short-term extensions of two to five years. As a result, at least 1.6 million acres of grassland in the PPR will likely revert to cropland over the next five years. This loss will have large-scale negative impacts on ducks and many other grassland-dependent species. Unfortunately, preliminary information on the CRP acres expiring between 2008 and 2010 suggests that re-enrollments will likely be offered on less than 10 percent of the acres in the PPR.
But ominous habitat trends are not limited to the U.S. side of the border. Significant wetland losses continue to occur across Prairie Canada. Because wetlands provide the key resources to attract breeding birds, the number of wetlands is the primary determinant of the local breeding population in an area. Draining or filling wetlands reduces the number of breeding ducks an area can support. Across the important PPR breeding areas in Canada, nearly 4 percent of remaining wetlands have been lost since 1984. The impact on breeding ducks is significant because the smallest wetlands support the greatest numbers of breeding pairs, and these small wetlands are the ones predominantly being lost.
On a positive note, the PPR of Canada has seen an increase in grassland acres. Between 1984 and 1999, the amount of cultivated land decreased by more than 9 percent. Agricultural programs such as Greencover Canada have also begun to produce positive results on the landscapes of the Canadian PPR. These programs have restored more than 160,000 acres of grassland in Alberta, Saskatchewan, and Manitoba. Ducks Unlimited Canada has played an integral role in the development of grassland restoration efforts.
These changes in grasslands and wetlands across the PPR have important implications for duck populations and hunting seasons. All the science suggests that the combination of fewer wetlands and more cropland will cause duck populations to decline. Breeding duck numbers will likely decline from more than 40 million observed during the latest population peak in the late 1990s and early 2000s. Harder to predict is how many more grassland acres will have to be lost or how many wetlands drained before we will see peak populations of only 30 million breeding ducks or less.
The impact large reductions in duck populations would have on hunting seasons is clear. Currently, the U.S. Fish and Wildlife Service bases season lengths and bag limits largely on the population of breeding mallards and the number of ponds counted in the Canadian PPR. Reductions in mallard populations of 25 to 30 percent would result in a best-case scenario of restrictive seasons with daily bag limits of three ducks in the Mississippi and Central flyways and four in the Pacific. Season length would be reduced to only 30 days in the Mississippi Flyway, 39 in the Central, and 60 in the Pacific. (Other criteria determine Atlantic Flyway regulations.) Greater reductions in duck populations could result in closed hunting seasons with serious social and economic consequences.
How can you help
The implications of continued habitat loss are sobering for all of us who have a passion for the ducks. But much can be done to prevent the gloomy scenario described earlier from coming to pass. First, DU is working with a broad coalition of conservation and commodity partners to ensure sound agricultural policies are crafted to benefit both agricultural producers and the ducks. DU is leading an effort to eliminate current incentives to convert native prairie to cropland (see sidebar on Sodsaver). DU is also working closely with conservation and commodity partners and congressional staff who will develop the next Farm Bill to ensure that adequate CRP acreage is maintained in the PPR, where it can continue to benefit ducks and other wildlife.
When Congress begins crafting the next Farm Bill, it will be critically important for all who have an interest in waterfowl to make their voices heard by calling or writing their congressional representatives. Regular updates and opportunities to take action will be posted on the DU website.
In addition, DU is working with the U.S. Fish and Wildlife Service to purchase perpetual grassland easements from landowners across the Dakotas and Montana. These landowners want to ensure their lands remain prairie grasslands. Currently, nearly 700 landowners have indicated interest in protecting more than 281,000 acres, but funding is insufficient to meet the demand. In this case, the science is clear, and the landowners are fully onboard. We just need the funding to protect the habitat.
Individuals interested in helping perpetually protect grasslands and wetlands on the most important duck breeding areas can now contribute funds directly to this effort. Simply go online at www.ducks.org and donate directly to DU's North American Grasslands Conservation Initiative or contact Dave Afton at DU's Great Plains Office (701-355-3511) about making major gifts in support of prairie habitat conservation.
Today, we face significant challenges across the continent's most important waterfowl breeding area. But the choices are clear for those who have a passion for waterfowl—either seize the opportunity to maintain the grasslands and wetlands needed to fill the skies with ducks, or lament the hollow legacy we will leave the next generation. If you care about the future of waterfowl, seize the opportunity now.