By Jim Ringelman, Ph.D.
It's tough to wrap your mind around some things. Like the size of the national debt or the number of humans inhabiting planet earth. I throw the Prairie Pothole Region (PPR) into this same mix of imponderables. More than 300,000 square miles in size, millions of wetlands, and tens of millions of breeding ducks. It seems impossible that the hand of mankind could cause much change in such a vast landscape. But we have. And we're threatening to do more damage in the next decade than in any time in recent history. What could be the effect on duck populations and duck hunting? Intriguing new analyses provide a troubling answer.
Recently, researchers compiled data from many sources to address the question "What causes the mid-continent mallard population to change?" The answer reaffirmed what many biologists have long suspected: Events that occur during the breeding season account for 84 percent of the variability in the mallard population growth rate (Figure 1). Surprisingly, deaths that occur during the nonbreeding season—including that from hunting—accounted for just 9 percent of the change in the population growth rate. And because mallard population ecology is similar to that of many other upland-nesting dabbling ducks, we now believe that mid-continent populations of these other species are regulated by the same set of factors—nesting success, hen success, and duckling and hen survival during the breeding season. This finding has big implications for duck hunters.
Of the top 10 harvested duck species, six of them achieve their highest nesting densities in the PPR, and two more split their breeding range between the prairies and forested habitats. Collectively, these eight species made up nearly 80 percent of the U.S. harvest in 2002-2003. Clearly, if you're a duck hunter, the chances are good that the PPR is supplying you with many, if not most, of the birds on your duck strap. The science is unequivocal, and it all points to the importance of the prairies. This is where Ducks Unlimited began its work 67 years ago, and where DU is focusing its resources in its efforts to save this imperiled ecosystem.
Keeping the Table Set
To understand DU's philosophy about prairie conservation, one must first recognize the most unique feature of the prairies: their dynamic environment. Floods and drought. Extreme heat and bitter cold. Occasional fires and gusty winds. The prairie ecosystem has not only evolved under these dynamic conditions, it requires them to maintain its productivity. Waterfowl have adapted to this variability by capitalizing on the fertility of reflooded prairie wetlands when good times prevail, and abandoning the region in times of drought. During the 50 years that biologists have tracked continental breeding populations, we have witnessed three peaks in duck populations, and two valleys. Each event coincided with times of wetland abundance or scarcity. Thus far, the pattern has been remarkably cyclic (Figure 2). Valleys of about 23 million ducks, peaks of roughly 40 million, and an average breeding population index of about 31 million birds. How can effective conservation programs be implemented in such a dynamic environment? By taking the long view of prairie conservation.
The long view acknowledges that duck populations will naturally build and decline as an inevitable consequence of wet periods and drought. No human intervention can change this reality. But because water and nesting cover are the two critical elements that determine annual production, what we can do is protect the wetland basins and the intact grasslands so that the table is set for the ducks when Mother Nature provides the right conditions. As we protect this baseline, we can also selectively implement wetland and grassland restorations to compensate for the extensive habitat loss that has already occurred. It's a dual-pronged approach that has served waterfowl conservation—and Ducks Unlimited—for almost seven decades.
Where large tracts of intact habitat still exist, it makes sense to emphasize the protection of these areas before they are lost.
Some detractors argue that securing the current base of habitat is not a suitable "stretch goal" for conservation, and a few maintain that this approach is flawed because it does not provide new, incremental ducks to the population. But those who espouse these viewpoints overlook the current trends and the pressures that exist in the PPR. The truth is, the prairies are under siege like no time since the mid-1970s, when farmers were urged to plow "fencerow to fencerow." A duck that is never added to the fall flight because of the drainage of a wetland or plowing of native grassland impacts population totals much the same as not producing an "additional" duck using more intensive management techniques. Moreover, in today's economy, guarding against the loss of habitat is usually a far wiser business decision than only costly restoration of habitat that is already degraded. For example, in much of the U.S. PPR, a one-time payment of $45-110 per acre can secure a perpetual grassland easement on the best waterfowl breeding habitat in the world. This is much more cost effective when compared to more intensive management techniques that can be 10 times as expensive. The highest priority, therefore, should be to protect the habitat base that provides for the duck population booms, like the one that occurred in 1993-1999. If we don't secure the intact habitats before they disappear, we will soon be in the unfortunate position of depending primarily on intensive management and expensive restorations.
But protecting the base is a credible approach only if the threats are genuine and losses are imminent. Are they? Let's examine the threats more closely.
President Bush recently announced that he continues to support no net loss of wetlands, and that is positive. However, the U.S. Supreme Court decision that removed isolated wetlands from protection under the Clean Water Act still stands. This is arguably the gravest threat to the PPR and to North American duck populations. The prairie potholes are the engines of the duck factory, and no amount of secure grasslands or intensive management can make up for their loss. Of additional concern is Canada's weaker wetland protection laws that have allowed relatively greater rates of loss than south of the border. Encouragingly, that trend is showing signs of reversing as Canadians embrace a renewed interest in wetlands conservation. But now that U.S. laws have effectively been weakened by the Court's interpretation, the only line of defense that still protects prairie pothole wetlands in the United States is the "swampbuster" provision of the Farm Bill. As with all such provisions, swampbuster is up for review every time a new Farm Bill is crafted. The next retooling is scheduled to begin in three or four years.
Second only to the wholesale loss of wetlands is the threat posed by the ongoing destruction of native prairie, the backbone of North American duck production. Big tracts of prairie are especially important, because duck nesting success increases with the amount of grassland in the landscape. Unfortunately, the much publicized "mad cow disease" (BSE, or bovine spongiform encephalopathy) has halted a recent trend that was favoring cattle ranching over cropping in parts of prairie Canada. In the blink of an eye, BSE now threatens the economic viability of the Canadian beef industry—and therefore grasslands—across much of prairie Canada.
In the United States, the conversion of native grassland to cropland has been accelerating, pushed by world demand for grain, by favorable loan rates, and by U.S. Department of Agriculture price supports. Of all the restorations performed by Ducks Unlimited, bringing back native prairie is one of the most challenging. Not only is it expensive—at least six times as expensive as an easement purchased to protect prairie from being destroyed in the first place—but it is also ecologically extremely difficult. When it comes to native prairie, an ounce of prevention is indeed worth a pound of cure.
If native grasslands are the cake that feeds the duck booms, then Conservation Reserve Program (CRP) lands are the frosting. Under CRP, landowners agree to plant and maintain grassland on their marginal cropland for a 10-year period in exchange for an annual government payment. The 4.7 million acres of CRP that are currently enrolled in North and South Dakota provide nearly ideal nesting cover. During 1992-1997, CRP contributed to a 30 percent improvement in duck recruitment rates and added an additional 12.4 million birds to the fall flight. But in 2007, 2.4 million acres of CRP contracts will expire in the Dakotas alone. That represents 51 percent of all the remaining CRP in these critical states. Another 1.4 million acres will come out of enrollment in 2008-2009. Acres coming out of the program today are not being replaced because of new national ranking factors for CRP that favor areas outside of the PPR. This change, coupled with attractive commodity price supports and upward trends in world grain demand, makes it questionable whether even a fraction of the CRP acreage will be re-enrolled. Fewer acres of CRP in the prairies will mean fewer ducks in North America.
Even though these are big issues, the solutions are fairly obvious. Wetlands can be secured through a combination of new laws and easements that compensate landowners for protecting potholes. Similarly, disincentives can be provided that help secure native grasslands, along with incentive-based approaches like purchased grassland easements that benefit both ranchers and ducks. The ranking systems for CRP can be changed again to reflect priorities that were present in the 1985 Farm Bill, when millions of acres were first enrolled in the PPR. These changes will take commitment and far-sighted leadership, but at least the path is clear. Unfortunately, the potential solutions to other threats are more elusive.
For example, scientists have discovered that prairie pothole wetlands are growing old before their time. For decades, soil and wind erosion has deposited about a quarter of an inch of sediment per year into the average prairie pothole. Not surprisingly, the deposition is worse in wetlands surrounded by cropland, as opposed to grassland. So what's the big deal about a quarter-inch of dirt? For one, that's all it takes to severely depress aquatic invertebrates that live a part of their life cycle in the mud of prairie wetlands. These invertebrates are the food source for many ducks during the breeding season. Moreover, since the average prairie pothole is only a few feet deep, a deposition rate of a quarter-inch per year means a three-foot-deep wetland will be filled completely in less than 150 years. Many prairie potholes have been surrounded by cropland and therefore have been subject to sediment deposition since the early 1900s.
Another unexpected source of concern for PPR ducks is biotech crops. New varieties of soybeans and wheat are not only more drought tolerant, but many also have an engineered resistance to nonselective herbicides. This makes them capable of growing in sites that are now devoted to ranching. The problem is most acute in central South Dakota, where biotech crops and world demand are fueling the destruction of tens of thousands of acres of prime pintail breeding habitat. Soybean fields don't grow pintails. Certainly, it's a poignant reminder that new technology has the potential to put all natural habitats at risk. The conversion of native prairie could accelerate rapidly with the introduction of biotech wheat, which seems destined to be widely adopted by farmers. In the PPR, where wheat is king and farm profitability is front-page news, vigorous debate has surfaced among farmers as to whether biotech crops should be grown.
Conservation and Society
Apart from the scientific arguments for and against the safety of biotech crops, the debate over their use provides a valuable insight for waterfowl conservationists. The lesson for waterfowl conservation is that science can develop solutions, but society must embrace their application.
DU is a science-based organization. Science has honed our knowledge of waterfowl biology; cutting-edge GIS computer software and LANDSAT satellite imagery have helped us target the highest priority landscapes, and we have a toolbox full of proven techniques. But these tools are implemented within a society that has competing viewpoints on how wetlands, grasslands, and ducks should figure into their future.
On both sides of the international border, those living in the PPR are facing similar problems. There is an out-migration of people. Small towns are being abandoned, and young people are leaving. Schools are being consolidated. The traditional economic driver, agriculture, is moving rapidly to large operations requiring relatively few people. It remains heavily dependent on government subsidies. Understandably, these concerns generate apprehension about the future, which promotes conservatism and a tendency to fall back on what has worked in the past, namely an agro-economy that continues to pressure wetlands and grasslands.
Biologists have a term for the maximum number of ducks that can be accommodated in a given area. It's called the biological "carrying capacity." In the PPR, where economic and social concerns weigh heavily on people's minds, the political carrying capacity for conservation is the amount of habitat that society feels should be set aside in fee-title ownership, conservation easements, and protected wetlands. Unfortunately, there is often a large gap between that political carrying capacity and the amount of secure habitat needed to assure the long-term future of breeding ducks. In the minds of many people, prairie wetlands and native grasslands are viewed as placeholders on the landscape, waiting to be converted to a better, more profitable use. Therein lies one of our biggest conservation challenges. The history of conservation is that society tends not to place a high value on natural features until those resources are almost gone. We cannot afford to repeat that lesson in the prairies.
Conservation organizations need to promote the economic and quality-of-life values of wetlands and grasslands, and DU is doing just that. In Canada, Ducks Unlimited has taken the lead in promoting agricultural policy reform. DU is actively working to ensure that policymakers recognize that establishment of perennial cover on marginal croplands provides societal values beyond ducks and other wildlife, including improved water quality, enhanced flood control, and soil conservation. Since these ecological goods and services are being provided by landowners, new agricultural policies should ensure that individuals who conserve habitat are compensated accordingly. Adoption and eventual broadening of such policies will be critical to our mission of restoring waterfowl habitat in the Canadian PPR. Greencover Canada, an agricultural program that pays for the conversion of cropland to perennial grassland, has recently been announced. This is a very positive first step, and will improve habitat conditions on acres that are enrolled, similar to the positive impacts of CRP in the United States.
In the United States, wetland and grassland easements purchased from willing landowners not only provide direct economic benefits, they also enable individuals to achieve their vision for the future of their land. This is a win-win situation that is popular with landowners and good for ducks. Likewise, habitat restorations and management can provide not only improved waterfowl habitat, but also economic returns in the form of hunting leases and nature-based tourism, and can also enhance the quality of human life on the land. In the new economy of the 21st century, where cyberspace shrinks the world down to size, individuals and companies are choosing to locate in areas that provide an enhanced quality of life. Landscapes that include open space, wetlands, natural plant communities, and wildlife figure prominently in the quality-of-life equation.
From Insights to Action
The British biologist Thomas Henry Huxley had it right when he said, "The great end of life is not knowledge but action." Fortunately, in the PPR, opportunity and knowledge have set the stage for action. Individuals and society are awakening to the importance of prairie wetlands and grasslands. Today, hundreds of ranchers are on waiting lists to sell conservation easements that will permanently protect critical habitat, yet we lack funding and staffing to meet the demand. Thousands of farmers would like to plant their existing cropland to grass under the Greencover Canada and CRP programs. However, eligibility criteria that select properties for CRP qualification are directing CRP away from the PPR in the United States, and Green-cover in Canada suffers for lack of funding. Much of society has come to recognize the value of wetlands for clean water and flood control, yet isolated wetlands have fallen out of legal protection under the U.S. Clean Water Act and have never received adequate protection in Canada. Everybody wants a good quality of life, and natural landscapes are a key element of that desire. Our challenge is translating this knowledge to action.
Clearly, we must pick up the pace. Many landowners are reaching retirement age, and when real estate changes hands, the new owners often consider alternative uses for the land. We need to become more vocal advocates for sound public policies that protect wetlands and grasslands, and we need to increase our personal and financial commitments to prairie conservation. While individual projects continue to be the building blocks of DU's work in the PPR, DU's vision of the final product has expanded greatly over the years. We are reaching for nothing less than securing for all time the waterfowl production capacity of the Prairie Pothole Region. The challenges are daunting, but the goal is achievable.