Measuring Conservation Success

How do current waterfowl populations and habitat levels stack up against the goals of the North American Waterfowl Management Plan?

By Mark Petrie, Ph.D., and Michael Anderson, Ph.D.

In the spring of 1988, the pilot-biologists of the U.S. Fish and Wildlife Service once again climbed aboard their aircraft. They were tasked, as they had been for 34 years, with estimating North America’s duck population. It is hard to imagine that they were optimistic. Even from the ground, they could see that much of the prairie remained locked in a nine-year drought.

A thousand miles to the south, men and women resigned themselves to the news. They also counted ducks, though usually in small neat piles carefully placed on the floor of their blinds. In fact, news coming out of the prairies had been bad for most of the 1980s. The 1970s gave us pet rocks, disco, and the Pacer, but it also provided folks with abundant duck populations and hunting opportunities that during the 1980s seemed faintly biblical.

There had been drought before, and there would be drought again. But by the mid-1980s, things felt different. There was a growing sense that the habitats needed by waterfowl were rapidly disappearing. Somewhere, somebody had calculated that waterfowl habitat was being destroyed at the rate of one acre per minute. Duck populations on the Canadian and U.S. prairies bottomed out in 1985 with the second-lowest count on record.

Managing waterfowl harvest had always been an international affair, but conserving waterfowl habitat often involved public agencies and private groups working in important but uncoordinated ways to meet the needs of North America’s waterfowl. All that changed on May 14, 1986, when the United States and Canada signed the North American Waterfowl Management Plan (NAWMP). Mexico would later sign in 1994.

The goal of the plan was straightforward but bold: restore North American waterfowl populations to levels observed during the 1970s. Although the goal was continental, the plan’s success would depend on regional efforts to increase waterfowl habitat. To that end, joint ventures of public agencies and private organizations, including DU, were formed in six areas that supported large numbers of breeding, wintering, or migrating waterfowl. In time, that number would grow to 22, including three species-oriented joint ventures with a strong research focus. These joint ventures merged and accelerated public and private efforts to carry out the work envisioned by the plan. The joint ventures translated the plan’s population goals into regional habitat goals and set out to achieve them.

In 2006, NAWMP marked its 20th anniversary. Although the plan has been updated three times, its biological impact had never been thoroughly evaluated. Where are we in restoring waterfowl populations to 1970s levels? In 2005, 13 waterfowl biologists from the United States, Canada, and Mexico (including the authors of this article) were asked to lead an assessment of NAWMP accomplishments. All 22 joint ventures in the United States and Canada were engaged in reporting their progress in meeting waterfowl needs.

So how should we judge success? The original plan’s goals were clear: return waterfowl populations to 1970s levels. One option was to simply examine duck numbers since 1986. Between 1994 and 2003, seven of the 10 most common duck species in the traditional survey area were as abundant or more abundant than they had been between 1970 and 1979. Only population estimates for pintails, scaup, and wigeon remained below 1970s levels, although pintail and scaup declines were steep. On the surface, then, it appeared that much had been done to meet the NAWMP goal, but there is a problem with this overly simplistic comparison.

The duck boom of the mid- and late 1990s coincided with a series of extraordinarily wet years, especially in the U.S. prairies. Moreover, the 1985 Farm Bill had created the Conservation Reserve Program (CRP), which eventually added nearly 8 million acres of nesting cover on the U.S. prairies. Together, these changes boosted duck production, but they obscured other less favorable trends in waterfowl habitat. Where would we stand when it stopped raining or if CRP disappeared from the Farm Bill? Simply comparing duck numbers over time could not give a true picture of how effective the plan had been and what remained to be done.

A second option was to consider how landscapes important to breeding, migrating, and wintering waterfowl had changed since 1986 and how these compared with the 1970s. To be clear, it has always been understood that duck populations will fall below NAWMP goals during periods of drought. Drought might wither our optimism for the next duck season, but it’s a necessary phase in a wetland’s life cycle. The important question is: Are NAWMP habitat efforts “setting the table” so to speak? When it does rain—and not necessarily in a way that Noah would recognize—can duck populations rebound as they did in the 1970s?

Since 1986, more than 13 million acres of waterfowl habitat have received some sort of protection, often permanent, as a result of joint venture efforts. Joint ventures have also restored or enhanced nearly 11 million acres of wetlands and upland nesting habitat in the United States and Canada. These acre accomplishments testify to the tremendous contribution made by joint venture partners over the past two decades. Unfortunately, in some places ongoing habitat losses have offset conservation gains, so assessing the net effects of landscape change on waterfowl is much more complicated. Thankfully, several joint ventures have invested tremendous effort in evaluating the effectiveness of their programs. Without such investments, evaluating NAWMP would have been impossible.

Evaluating the true impact of NAWMP, or estimating what additional conservation gains must be made, requires knowledge of two fundamental things: how important waterfowl landscapes have changed in terms of wetland or grassland abundance and how these landscape changes have affected waterfowl populations in terms of survival and reproduction. In some places, such as the Prairie Pothole Region (PPR), great strides have been made in developing this essential biological foundation.

In a single magazine article, it is not possible to report on all 22 joint ventures across the United States and Canada. Instead, we have combined joint ventures into those that largely support wintering and migrating waterfowl, and the two joint ventures that are responsible for conserving breeding habitat on the U.S. and Canadian prairies.

Wintering and Migration Areas

Setting hunting aside, the survival of migrating and wintering waterfowl appears to depend mainly on food supplies. Thus, as a first approximation, changes in available foraging habitat can be used to measure progress in meeting the needs of nonbreeding waterfowl. By this standard, many joint ventures have produced substantial gains in foraging habitat since 1986, including those that winter a significant percentage of North America’s hunted waterfowl. For example, joint ventures in both the lower Mississippi Alluvial Valley and the Central Valley of California have reported large increases in foraging habitat, with food supplies now able to support 1970s populations in all but the driest winters.

The plan’s success in many wintering and migration areas stems from a combination of biological and economic factors. First, relatively small areas can support large numbers of nonbreeding waterfowl, whereas on breeding areas, ducks naturally space themselves at low densities. Second, combining public programs like the Wetlands Reserve Program and the North American Wetlands Conservation Act with private resources provided by DU and other joint venture partners has made it possible to achieve net wetland gains in many, though not all, nonbreeding areas.

While wetland restoration has helped provide gains in foraging habitat, much of the food needed by wintering waterfowl still occurs on unprotected agricultural lands. Joint ventures have worked with landowners to promote waterfowl-friendly practices like winter flooding of harvested rice fields. Although these habitats are likely to be important in the near future, changing farm practices and agricultural markets are largely beyond joint venture control. Continued efforts to restore and protect wetlands that provide waterfowl with natural foods will increase the long-term reliability of wintering and migration habitat.

U.S. Prairie Pothole Region

For nine straight years between 1994 and 2002, breeding duck populations met or exceeded the plan’s objectives for the U.S. prairies. None of this was lost on members of the Prairie Pothole Joint Venture. They recognized that the region was capable of meeting NAWMP goals in its current state. The table was already set; the challenge would be to maintain it.

Heavy rain and snow, CRP, and the efforts of Prairie Pothole Joint Venture partners all contributed to the duck boom. In hindsight, wetland protection in the years before the boom had been especially critical. Swampbuster (a Farm Bill program that discourages wetland drainage), wetland easement programs, and the Clean Water Act had maintained wetland basins capable of attracting large numbers of breeding waterfowl when water returned to landscapes enriched by new expanses of nesting cover.

But there are serious challenges ahead. More than 5 million acres of CRP on the U.S. prairies will expire between 2007 and 2010. Nearly 2.8 million acres will expire in 2007 alone. While some of these acres will be re-enrolled, even partial loss of CRP will reduce the upland cover that helped fuel the duck recovery on the U.S. prairies. Alarmingly, during a time when CRP converted 8 million acres of cropland to cover, nearly 3 million acres of native grassland were converted to cropland. Thus, NAWMP programs in the absence of CRP were not able to maintain pre-1986 conditions, let alone realize net gains in upland cover. Finally, Supreme Court decisions regarding the Clean Water Act have reduced federal protection for prairie potholes, leaving Swampbuster as the primary defense against drainage. Moreover, Swampbuster is merely a provision of the Farm Bill, not a law, and it has been repeatedly challenged.

While CRP was not a product of NAWMP, plan partners have worked tirelessly over the past 20 years to see it maintained and targeted toward duck country. The outright loss of CRP would make it extremely difficult to meet the plan’s objectives for the U.S. prairies. In recognition of this, the Prairie Pothole Joint Venture has increased its protection goals to include 10 million acres of grasslands and 1.4 million acres of wetlands, most of which would be accomplished using conservation easements. While this is a fivefold increase over the joint venture’s original habitat objectives, achieving it will help ensure that the U.S. Prairie Pothole Region can permanently support the duck numbers envisioned by NAWMP, even if support for CRP falters.

Canadian Prairie Pothole Region

While land use on the Canadian prairies has improved for waterfowl since 1986, the region is still unable to support 1970s duck populations during periods of average precipitation. Today, the Canadian PPR hatches about 7 percent fewer nests than it did in 1971. Encouragingly, grasslands have been restored on 6 million acres in Prairie Canada since 1986, when NAWMP was signed, resulting in important gains of critical nesting cover. Most of this cropland was converted to hay land or pasture in response to improved market forces that favor cattle production. While native grasslands were lost during this period, the overall change in nesting cover appears to have  positively affected the number of hatched nests.

The main culprit is wetland loss. Some large regions of the prairies have lost nearly 8 percent of their wetlands since 1971 with the rate of loss continuing during the past 20 years. As a result, the Canadian duck factory can support fewer breeding pairs under similar moisture conditions than it did 35 years ago, and habitat gains achieved during the past 20 years by NAWMP have been largely offset by wetland loss on unprotected lands. 

Although the Canadian Prairie Habitat Joint Venture has permanently secured nearly 500,000 acres of excellent habitat, the joint venture has long recognized that land acquisition programs alone will not achieve NAWMP population goals, even with increased funding. The region is simply too vast. Large set-aside programs like CRP are also unlikely because the Canadian tax base is too small to support such a subsidy program, and there is little interest in the agricultural community for removing large amounts of land from production. Nevertheless, Agriculture Canada’s new Greencover program has made some progress in this area, and new wetland conservation policies are presently being developed in each Canadian province.

The solution to the Canadian duck problem appears to lie mainly in policy initiatives that can produce positive changes across large landscapes. First and foremost are efforts to increase protection for wetlands. We stand little chance of returning to 1970s populations (the NAWMP goal) if we cannot halt wetland loss. Programs that restore lost wetlands, especially small shallow basins, are also needed. In addition, perennial upland cover must be maintained and restored where possible.

Recent changes in Canada’s Agricultural Policy Framework (the country’s “farm bill”) are encouraging. There is growing awareness that landowners who maintain wetland and upland habitats provide society with real benefits beyond wildlife habitat and that these landowners should be rewarded in some tangible way. The Prairie Habitat Joint Venture is working to make such programs possible and has already had success in developing conservation easement legislation that was formerly lacking for Canada. The Prairie Habitat Joint Venture has also helped researchers develop crop alternatives like cold-hardy winter wheat that can provide extensive tracts of spring nesting cover, which has been shown to significantly increase duck production. The Canadian PPR is largely in private ownership, and conservation solutions are being pursued vigorously in concert with farmers and ranchers.

Moving Forward

Authors of the 1986 plan hoped we would reach our goals in 15 years. In the 20 years since NAWMP was signed, much has been accomplished, but much remains to be done. The joint venture model has stimulated some of the most successful partnerships of public and private interests in the history of wildlife management. As a result of this recent assessment, plan partners have better defined the challenges faced by waterfowl and the programs needed to fully meet NAWMP goals. Seeing these challenges through will fall to this and the next generation of waterfowl enthusiasts and beyond.

The authors wish to thank their fellow biologists who took part in the NAWMP evaluation, and especially the joint venture partners that made it possible. The complete NAWMP report can be found at www.fws.gov/birdhabitat/NAWMP/files/DraftContAssess.pdf.