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Natural Resource Management Faculty Publications Department of Natural Resource Management

2014 Issues Affecting Waterfowl Conservation in Heath M. Hagy University of Illinois at Urbana-Champaign

Scott .C Yaich

John W. Simpson Winous Point Marsh Conservancy

Eduardo Carrera Ducks Unlimited Mexico

David A. Haukos Texas Tech University

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Recommended Citation Hagy, Heath M.; Yaich, Scott .;C Simpson, John W.; Carrera, Eduardo; Haukos, David A.; Johnson, W.Carter; Loesch, Charles R.; Reid, Fritz A.; Stephens, Scott E.; Tiner, Ralph W.; Werner, Brett A.; and Yarris, Greg S., "Wetland Issues Affecting Waterfowl Conservation in North America" (2014). Natural Resource Management Faculty Publications. 256. https://openprairie.sdstate.edu/nrm_pubs/256

This Article is brought to you for free and open access by the Department of Natural Resource Management at Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. It has been accepted for inclusion in Natural Resource Management Faculty Publications by an authorized administrator of Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. For more information, please contact [email protected]. Authors Heath M. Hagy, Scott .C Yaich, John W. Simpson, Eduardo Carrera, David A. Haukos, W.Carter Johnson, Charles R. Loesch, Fritz A. Reid, Scott E. Stephens, Ralph W. Tiner, Brett A. Werner, and Greg S. Yarris

This article is available at Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange: https://openprairie.sdstate.edu/nrm_pubs/256 343

Wetland issues affecting waterfowl conservation in North America

HEATH M. HAGY1*, SCOTT C. YAICH2, JOHN W. SIMPSON3, EDUARDO CARRERA4, DAVID A. HAUKOS5, W. CARTER JOHNSON6, CHARLES R. LOESCH7, FRITZ A. REID8, SCOTT E. STEPHENS9, RALPH W. TINER10, BRETT A. WERNER11 & GREG S. YARRIS12

1*Illinois Natural History Survey, Forbes Biological Station – Bellrose Waterfowl Research Center, University of Illinois at Urbana-Champaign, Havana, Illinois 62644, USA. 2Ducks Unlimited, One Waterfowl Way, Memphis, Tennessee 38120, USA. 3Winous Point Marsh Conservancy, 3500 S Lattimore Road, Port Clinton, Ohio 43452, USA. 4Ducks Unlimited Mexico, Ave. Vasconcelos 209 Ote. Residencial San Agustin, Garza Garcia, Nuevo León, Mexico. 5U.S. Fish and Wildlife Service, Texas Tech University, Lubbock, Texas 79409, USA. 6Department of Natural Resource Management, State University, Brookings, South Dakota 57007, USA. 7U.S. Fish Wildlife Service, Habitat and Population Evaluation Team, Bismarck, 58501, USA. 8Ducks Unlimited, 3074 Gold Canal Drive, Rancho Cordova, California 95670, USA. 9Ducks Unlimited Canada, P.O. Box 1160, Stonewall, ROC 2ZO, Canada. 10U.S. Fish and Wildlife Service, 300 Westgate Center Drive, Hadley, Massachusetts 01035, USA. 11Program in Environmental Studies, Centre College, 600 West Walnut Street, Danville, Kentucky 40422, USA. 12Central Valley Joint Venture, 2800 Cottage Way, Sacramento, California 95825, USA. * Correspondence author. E-mail: [email protected]

Abstract This paper summarises discussions by invited speakers during a special session at the 6th North American Duck Symposium on wetland issues that affect waterfowl, highlighting current ecosystem challenges and opportunities for the conservation of waterfowl in North America. , invasive species, U.S. agricultural policy (which can encourage wetland drainage and the expansion of row-crop into grasslands), cost and competition for water rights, and wetland management for non-waterfowl species were all considered to pose significant threats to waterfowl populations in the near future. Waterfowl populations were found to be faced with significant threats in several , including: the Central Valley of California, the

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Playa Lakes of the south-central U.S., the Prairie Pothole Region of the northern U.S. and western and , the boreal forest of , the and . Apart from direct and indirect threats to habitat, presenters identified that accurate and current data on the location, distribution and diversity of wetlands are needed by waterfowl managers, environmental planners and regulatory agencies to ensure focussed, targeted and cost-effective wetland conservation. Although populations of many waterfowl species are currently at or above long-term average numbers, these populations are thought to be at risk of decline in the near future because of ongoing and predicted nesting habitat loss and wetland destruction in many areas of North America.

Key words: agriculture, climate change, dabbling duck, national wetlands inventory, playa, policy, prairie pothole.

To the casual observer, it might seem that populations and also the number of May wetland-dependent wildlife face few appear to be near or above levels conservation issues at present in North observed in the early 1970s and late 1990s, America. Dahl (2006) showed a 0.3% gain in both periods thought to be the “good old deepwater and wetland area in the days” by waterfowl conservationists (Vrtiska continental United States (i.e. excepting et al. 2013). Moreover, waterfowl hunting Alaska and Hawaii) between 1998 and 2004. regulations have remained liberal since the During the early 21st century, numbers of introduction of the Adaptive Harvest breeding ducks have remained at or above Management programme in 1995, allowing their long-term average population for maximum take (regulated by bag limits) estimates, and populations of several of most species (Nichols et al. 2007; Vrtiska species (e.g. Blue-winged Teal Anas discors et al. 2013). and A. clypeata) are at all- Despite currently large waterfowl time highs (USFWS 2013). Even Lesser population sizes, many threats loom that Scaup Aythya affinis and cause informed wetland and waterfowl Anas acuta populations have reversed conservationists to worry about the future. historical declines and seem to be steady or Dahl (2011) documented a loss in wetland increasing in number. The abundance of area and only modest gains in the number of ponds and wetlands containing water in May all wetlands and deepwater habitats (i.e. “May ponds”) in breeding areas combined during 2004–2009. Additionally, surveyed annually by the U.S. Fish and losses in vegetated wetlands have been Wildlife Service and the Canadian Wildlife largely offset by gains in agricultural and Service, which serves as an indicator of urban ponds and other non-vegetated wetland habitat availability and waterfowl wetlands, which likely are of less value to productivity, was 42% above the long- waterfowl, other waterbirds and other term average in summer 2013. Breeding wildlife (Weller & Fredrickson 1974; Dahl

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2011). Also of concern is that wetland Recognising the ongoing and increasingly losses have not been evenly distributed significant threats to wetlands and wetland among regions and systems; for instance, wildlife, the Wetlands Working Group of losses in the Prairie Pothole Region and the the Wildlife Society held a special session lower Mississippi Alluvial Valley, which at the 6th North American Duck provide some of the most important habitat Symposium – “Ecology and Conservation for breeding and wintering waterfowl of North American Waterfowl”, to describe in North America, have been more and summarise issues affecting wetland pronounced than in other regions (Dahl conservation relating to waterfowl in North 2011; Johnston 2013). Unfortunately, we can America. Here we present topics discussed expect that current May abundance at this session and provide an overview of and waterfowl breeding population size are current wetland issues affecting waterfowl facing probable declines in the future conservation in North America. Our (Johnson et al. 2010; Johnston 2013). objectives are to: 1) outline the growing Agricultural policies that have long provided threats to wetlands and waterfowl in some protection for geographically-isolated North America, 2) generally highlight wetlands through the “Swampbuster” current research and management that provision in the U.S. Farm Bill now addresses these issues, and 3) provide contain reduced or increasingly ineffective recommendations for future actions that conservation provisions. Incentive-based may benefit wetland and waterfowl wetland restoration, creation and protection conservation in North America. programmes also face declining funding or elimination. Furthermore, mandates for Wetland policy ethanol production (i.e. the Renewable Fuels Standard) coupled with crop insurance The United States policies have provided incentives for In the minds of biologists, hunters and the wetland drainage in the U.S. general public, waterfowl are stereotypically (Reynolds et al. 2006; Johnston 2013). and appropriately linked to wetlands and Reductions in federal spending and relatively other aquatic habitats. Yet, while the high waterfowl populations may dissuade waterfowl management and scientific policy makers from prioritising wetland community has dedicated substantial conservation policies in future Farm Bills. resources to population and habitat For these and many other reasons that management, there has been much less will be highlighted subsequently, we effort devoted to providing the scientific deemed it necessary to convene a forum foundation for securing policies that where scientists and conservation leaders maintain wetland habitats. The success or could discuss current wetland policy failure of these policies in maintaining the and management issues that may affect ’s wetland habitats will ultimately waterfowl conservation efforts in the near determine the level of success achievable by future. waterfowl conservationists.

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The series of wetland status and trends wetland losses and the incentives towards reports produced by the United States Fish maintaining and restoring wetlands were and Wildlife Service (USFWS) from the reflected in a net rate of loss 79% lower mid-1950s through to 2009 provides than that of the 1950s–1970s (Dahl evidence of the impact of policies on 2000). The trend of increasing broad and wetlands in the U.S. The first report, protective wetland policies continued examining the mid-1950s to the mid-1970s through the early 1990s, and by 2004 the net (Frayer et al. 1983), documented a loss of loss rate of wetlands most important to 113 million acres (c. 46 million ha) of waterfowl and other wildlife had declined to wetlands with net losses approaching a half- approximately 80,000 acres (c. 32,000 ha) per million acres (c. 202,000 ha) annually. year (Dahl 2006). However, implementation of the Clean However, the tide of wetland Water Act (CWA) in the mid-1970s conservation policy turned in 2001 with the provided some degree of federal protection U.S. Supreme Court in favour of the Solid to most wetlands, including the prairie Waste Agency of Northern Cook County’s potholes of the north- (SWANCC) appeal against the presence of and Canada, a key region for waterfowl migratory birds being used as the sole production. The status and trends report for determinant for the U.S. Army Corps of the mid-1970s to the mid-1980s (Dahl & Engineers’ (USACE) jurisdiction over Johnson 1991) documented a slowing of the waters of the United States (SWANCC versus national rate of net wetland loss to USACE). The Supreme Court’s decision approximately one-third of pre-CWA rates. greatly narrowed the perceived jurisdiction In 1985, the Swampbuster provision of the of the Corps to regulate the drainage and federal U.S. Farm Bill, which stopped infilling of wetlands not adjacent to open agricultural subsidy payments to landowners and clearly navigable waters (Dahl 2011). who drained wetlands for farming (Dahl In response, the U.S. Environmental 2011; Johnston 2013), added another critical Protection Agency and USACE withdrew layer of protection to many wetlands at risk federal protections of being drained for agricultural uses. from broad swaths of wetland categories, To complement the regulatory including so-called “geographically isolated protections of the Clean Water Act and wetlands” such as the prairie potholes, disincentives of Swampbuster, voluntary rainwater basins and playa wetlands of the incentive-based wetland conservation Great Plains (Haukos & Smith 2003). At the programmes such as the Wetland Reserve same time, funding for many of the Program, the North American Wetlands incentive-based conservation programmes Conservation Act, the Conservation peaked and has since declined. Reserve Program and the USFWS Partners The findings of the most recent for the Fish and Wildlife Program were assessment of wetland status and trends established in the late 1980s and 1990s. (Dahl 2011) mirrored this shift in Concurrently, regulatory deceleration of conservation policy. For the first time in 50

©Wildfowl & Wetlands Trust Wildfowl (2014) Special Issue 4: 343–367 Wetland issues affecting waterfowl 347 years, wetland loss accelerated, increasing by makes maintaining an adequate wetland 140% compared with 1998–2004. Policy- base to support healthy populations of based funding for wetland conservation breeding ducks impossible without wetland programmes has continued to decline, and regulations that reduce loss rates. changes to Farm Bill policy place c. 1.4 In , implementation of a new million wetlands in the Prairie Pothole Region wetland policy provides some wetland of North and South Dakota at high risk of protection and requires mitigation at a ratio being drained and lost (Reynolds et al. 2006). determined by the value of the affected wetland. However, although the new policy Canada is largely enforced for developers and the In the Prairie Pothole Region of Canada, energy sector, it is not applied consistently wetlands represent a significant obstacle to to agriculture (S. Stephens, pers. comm.). production agriculture. As a result, wetland In , policy prohibits the drainage continues to occur despite growing drainage of water from wetlands from evidence of ecological goods and services an individual’s property onto another that wetlands provide, including flood landowner; however, these regulations have protection, carbon storage and been poorly enforced, resulting in conflicts recharge (Millar 1989). The jurisdiction for between neighbouring producers and Canadian wetland policy resides at the significant unauthorised drainage across provincial level (Rubec et al. 1998). As a Saskatchewan. In Manitoba, existing policy result, effective policies that protect existing protects semi-permanent and permanent wetlands must be developed for each ponds and lakes (Stewart & Kantrud 1971), provincial jurisdiction if wetlands across but shallower and more ephemeral wetlands Canadian landscapes important to remain unprotected from drainage. waterfowl, such as the Prairie Pothole Given the different stages of progress on Region, are to be protected effectively. and viewpoints regarding wetland policy High commodity prices and several years amongst the three provincial governments of above normal precipitation have resulted spanning prairie Canada, unique strategies for in high rates of wetland drainage to facilitate improving wetland policy and subsequent increased areas being put to agricultural enforcement of regulations require diverse production across the Prairie Pothole and nuanced approaches for each province. Region. For example, Ducks Unlimited Currently, conservation advocates such as Canada recently estimated that in Ducks Unlimited Canada pursue strategies Saskatchewan alone > 6,000 ha of wetlands such as building a network of grassroots were being drained on an annual basis advocates and developing an understanding (Ducks Unlimited Canada, unpubl. data). of how best to engage with those grassroots When contemporary cost estimates for advocates in the process, providing support wetland restoration are applied, the costs of to affected landowners, building coalitions restoring those drained wetlands would be with agricultural industry groups around > US$65 million. This rate of wetland loss support for wetland policy, building stronger

©Wildfowl & Wetlands Trust Wildfowl (2014) Special Issue 4: 343–367 348 Wetland issues affecting waterfowl relationships with provincial staff and on regions with significant wetlands. Once ministers in key ministries, developing new in place, these inventories may prove useful science to support the economic and as the foundation for promoting subsequent ecological case for wetland regulation and conservation activities by local, state and developing a wetland monitoring system to federal governmental entities, as well as non- facilitate measuring the impact of new governmental conservation organisations. wetland policies or lack thereof. Additionally, inventories provide guidance to outside funding institutions that can help Latin America target the allocation of resources to places Latin American countries have only and activities that can generate the greatest relatively recently come to recognise the conservation return for their investment. importance and value of their wetlands To optimise wetland and waterfowl and begun to focus more attention on conservation in the Latin American and wetland conservation. In this region, earlier region, these nations and funding public policy efforts directed at natural organisations should consider directing resource conservation focused primarily significant public policy effort toward the on establishing systems of state and development of national conservation plans federal protected areas, but wetland that include wetlands inventory data. These protection was not usually a driving force conservation plans should identify the most behind site designations. As a result, past important habitats, provide information wetland conservation tended to be largely regarding the most significant site-specific coincidental. conservation challenges, and propose More recently, the Ramsar Convention’s pragmatic actions and policies that will need initiative to identify and protect Wetlands of to be implemented to ensure long-term International Importance (“Ramsar Sites”) conservation and sustainable use of these has become an important mechanism wetlands and other wildlife habitats. The for promoting explicit recognition of continued loss and degradation of many the importance of wetlands and has important wetland ecosystems, despite the focussed additional attention on wetland existence of various international agreements conservation in Latin America. In countries and national policies, underscores the including Mexico, Colombia, Venezuela, importance of developing realistic but Argentina, Chile and Brazil, government effective conservation plans that involve and interest in the designation of Ramsar acknowledge the needs of all stakeholders in Sites has been responsible for spurring Latin America. the development of national wetlands inventories and classification systems. For Important wetlands at-risk example, Mexico has made considerable progress in recording and classifying Playa wetlands habitats across the entire country, with an Playas are dynamic, small, recharge wetlands explicit emphasis and priority being placed located in the High Plains region of the

©Wildfowl & Wetlands Trust Wildfowl (2014) Special Issue 4: 343–367 Wetland issues affecting waterfowl 349 western Great Plains in the central U.S. With source and associated methodology used to ecological conditions that reflect the harsh, identify playas, with published figures unpredictable environment of the High ranging from 30,000–80,000 playas (Smith et Plains, playas form a complex system al. 2012; D. Haukos, pers. comm.). Although providing numerous ecological functions the large number of playas reported as and services, including habitat for migratory present on the landscape gives the mistaken waterfowl (Haukos & Smith 1994). Essential impression that there are sufficient to playa function is the erratic fluctuation functional playas capable of providing between wet and dry states that creates a ecological services for waterfowl, Johnson et diversity of playa conditions or habitats al. (2012) estimated that 17% of historical throughout the entire High Plains (Smith playas are no longer detectable on the et al. 2012). Inundation patterns and southern Great Plains (Oklahoma, Texas hydroperiods of playas vary annually with and New Mexico). In addition, only 0.2% of the average playa being inundated during existing playas have no wetland or watershed January once every eleven years in Texas and modification. Further, Johnson et al. (2012) New Mexico (Johnson et al. 2011a). estimated that 38.5% of historical playas Playas provide habitat for migrating, had been lost from the landscape or wintering and breeding waterfowl (Ray et al. experienced cultivation of the hydric soils, 2003; Baar et al. 2008; Haukos 2008). The which can greatly reduce or eliminate natural number of inundated playas during winter forage for waterfowl. The greatest threat determines the number of wintering to playas is unsustainable sediment waterfowl; Johnson et al. (2011a) reported accumulation (Luo 1997; Smith 2003; Tsai that the percent of inundated playas varied 2007). Combining physical wetland loss, from near zero in dry years to > 50% in wet direct wetland cultivation and fill due to years. During wet years, overwinter survival sediment accumulation results in an of Anas platyrhynchos and Northern estimated 60% of historical playas that are Pintail in the High Plains is greater than for no longer available to provide habitat for any other wintering area in North America waterfowl (Johnson et al. 2012). Of the (Bergan & Smith 1993; Moon & Haukos remaining playas on the southern Great 2006). Estimated numbers of wintering Plains, none are fully functional (Johnson ducks using southern playas during January 2011b). These impacts to playa ecosystems ranges between 200,000 and 3 million likely contributed to the 32% decline in depending on environmental conditions average body condition of Northern Pintail such as precipitation levels and winter from the mid-1980s to early 2000s (Moon temperatures (USFWS 1988; Haukos 2008). et al. 2007), with potential associated The historical number of playas is cross-seasonal effects on survival and unknown because of extensive landscape reproductive capacity (Mattson et al. 2012). alteration in the High Plains during the past Despite the acknowledged value of playas century (Smith et al. 2012). Recent estimates to waterfowl, conservation efforts have of playas vary greatly depending on the been stymied during the past three decades.

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The vast number of playas, and the lack that these actually drive playa ecosystems. of perceptible physical differences in Relatively long temporal periods may exist their characteristics (excepting inundation between ecological states that provide high frequency) which provide value as wildlife quality habitat for waterfowl. Finally, any habitat or contribute to ecological goods conservation effort must consider the role and services, have paralysed efforts to and contribution of individual playas to the conserve these wetlands. The value of entire system when prioritising playas for playas is greatest when they are considered conservation. Despite recognition of use of in aggregate and regionally, although this playas by waterfowl, the capacity of the approach is rarely used in conservation playa system to support waterfowl is efforts (Smith et al. 2011; Johnson et al. declining (Moon & Haukos 2006; Moon et 2012). Finally, there is lack of federal and al. 2007; Smith et al. 2011). Consequently, state regulations or incentives to encourage a multifaceted approach is needed to the protection of playas, and no develop a playa conservation strategy that requirement to mitigate for any negative includes: 1) an educational effort to impacts on playa wetlands (Haukos & Smith accumulate support for playa conservation, 2003; Johnson et al. 2011b). The U.S. 2) modification of current conservation Department of Agriculture’s Conservation programmes so that playas are competitive Reserve Program, which has limited focus for funding, and 3) greatly accelerating on wetlands compared with other habitats research efforts to accumulate knowledge within the programme, is the main relative to playa ecology, management and conservation initiative affecting playas on their status across the landscape. the High Plains. Unfortunately, playas in Conservation Reserve Program watersheds Boreal forest wetlands have altered hydrology characterised by North America’s boreal forest (hereafter, reduced inundation frequency and Boreal) is part of the largest terrestrial biome hydroperiod possibly resulting from use of and unspoiled wetland and forest ecosystem non-native vegetation in CRP plantings in the world. This 600 million ha landscape (Cariveau et al. 2011; Bartuszevige et al. 2012; stretches from western Alaska to Labrador O’Connell et al. 2012). and accounts for > 35% of the continent’s Conservation efforts should be forest-cover (Wells & Blancher 2011). coordinated at larger spatial and temporal Wetlands comprise 6% of the earth’s land- scales to identify accurately the value of an cover, yet Canada alone has 25% of the individual playa. Moreover, conservation world’s wetlands (PEG 2011). Most of programmes need to be tailored specifically Canada’s wetlands (> 85%) are in the Boreal, to playas as current efforts are not effective including bogs, fens, swamps, marshes and (Bartuszevige et al. 2012; O’Connell et al. open water basins. Alaska’s Boreal has 2012). Efforts to conserve playas will > 2,000 rivers and streams that feed a water- benefit from recognition that extreme rich wetland landscape. North America’s environmental conditions are normal, and Boreal holds 25% of the freshwater and

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> 30% of soil carbon on the planet (PEG (> 40 ha in area) due to the melting of 2011). Despite their former isolation and permafrost, increased evaporation and vast coverage, North America’s Boreal transpiration rates, and aggregation of wetlands face increasing threats from climate floating emergent vegetation and associated change and expansion of industrial activities. inorganic sediments, resulting in regional Prairie and boreal wetlands provide decreases in area (Smith et al. breeding habitat for the majority of duck 2005; Riordan et al. 2006; Roach et al. 2011). pairs across North America (Slattery et al. The extent of these changes across the 2011). Breeding season population estimates Boreal is currently unknown, but substantial for the western Boreal region alone are increases are expected. 13–15 million birds, with many species While increasing temperature may having ≥ 50% of their breeding populations represent a threat beyond the control of in the Boreal (Wells & Blancher 2011). The classic waterfowl conservation mechanisms, prairie and boreal biomes are arguably other more direct anthropogenic landscape integrated ecologically as ducks may use the changes may be more amenable to Boreal for nesting during prairie droughts sustainable development. Changes to and annual wing moult (Baldassarre & Bolen hydrology can result in long-term drying (e.g. 2006). Consequently, extensive changes to Bennett Dam on the Peace-Athabasca Delta) boreal waterfowl habitat could have or flooding (e.g. Ramparts Dam proposed for continental-level implications for waterfowl the Yukon River and also several large conservation objectives. operations in Quebec). Water pollution can The perception of a pristine Boreal has potentially reach large blocks of watersheds changed rapidly because of the wide range of because Boreal wetlands are often development activities occurring there, and hydrologically connected through subsurface development is predicted to increase flow (Smerdon et al. 2005). Timber harvest substantially into the future (Bradshaw et may increase runoff and thus local flooding, al. 2009; Wells 2011). Seven distinct and this can have a direct effect on the anthropogenic pressures threaten the North breeding success of cavity-nesting birds. American Boreal, including agricultural Road construction can impound or drain expansion, petroleum exploration and water flowing to or from wetlands. We are development, forestry, hydroelectric only just beginning to understand the impact development, mining, acid precipitation and of these factors on waterfowl and their climate change. Few regions have already and habitats, which challenges conservation are expected to experience greater changes in efforts and necessitates a cautious approach mean temperatures than the Boreal (Soja et to development and wildlife management in al. 2007; Bradshaw et al. 2009; Stocker et al. the region. 2013), yet this biome has a great influence on Protection of water quality, quantity and global temperature and carbon storage hydrologic patterns appears critical to (Bonan 2008). Impacts on Boreal wetlands conservation of waterfowl habitat within may include loss of lakes and wetlands the Boreal. Because most Boreal wetlands

©Wildfowl & Wetlands Trust Wildfowl (2014) Special Issue 4: 343–367 352 Wetland issues affecting waterfowl recharge through lacustrine or riverine threaten wetland function and value for processes, those in the Alaskan boreal forest waterfowl in the Prairie Pothole Region are protected under the U.S. Clean Water (Johnston 2013; Wright & Wimberly 2013). Act, but recent Supreme Court decisions Prairie wetlands have been identified as (e.g. SWANCC versus USACE) have muddied particularly vulnerable to climate change. the jurisdictional waters for many wetlands Evidence for this conclusion has come not immediately adjacent to navigable rivers from an inter-institutional and multi- or streams. In contrast there is almost no disciplinary team of investigators which broad wetland protection in Boreal Canada, has developed and used two simulation either at the federal or provincial/territorial models, WETLAND SIMULATOR and levels, although recent legislation in Alberta WETLANDSCAPE, to project future may provide some level of protection. consequences of climate change on prairie Widespread and enforceable legislative wetlands and waterfowl (e.g. Poiani & protections are critical to ensuring that the Johnson 1991; Poiani et al. 1995, 1996; Boreal can support key North American Johnson et al. 2005, 2010; Werner et al. 2013). waterfowl populations into the future. These researchers have reached four main conclusions after 20 years of research on Prairie wetlands the subject: 1) temperature matters, 2) Wetlands potentially represent the most geography matters, 3) impacts may have critical and limiting components of the already occurred, and 4) threshold effects landscape for breeding waterfowl (Kantrud may yield future surprises. A representative & Stewart 1977). The Prairie Pothole Region simulation using weather data (1986–1989) of the north-central United States and south from the Orchid Meadows field site central Canada produces up to 75% of demonstrated the effect of increasing air waterfowl in North America (Smith et al. temperature on the length of time that water 1964; Mitsch & Gosselink 2007). Wetland stands (hydroperiod) in a semi-permanent density in this region ranges from 4–38 wetland basin (Johnson et al. 2004, 2010). potholes/km2 (Baldassarre & Bolen 2006), Raising the temperature a modest 2°C but more than half of the original wetlands shifted wetland permanence type from in the region have been lost or highly semi-permanent (not dry during the 4-year modified, principally for agriculture (Mitsch simulation) to seasonal (drying annually). A & Gosselink 2007). Moreover, conversion 4°C increase changed the wetland into one of native grassland and pastures to row- more typical of a temporary wetland that crop agriculture can have a dramatic effect dried by late spring or mid-summer each on wetland integrity by increasing sediment year. This simulation, and hundreds more and chemical runoff within the watershed that have been completed across the Prairie (Zedler 2003). A myriad of factors including Pothole Region (e.g. Poiani et al. 1996; Poiani agricultural policy, changing wetland & Johnson 2003), clearly illustrate how regulations, improved farming and land sensitive prairie wetland hydrology is to air clearing technology, and climate change temperature.

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The Prairie Pothole Region is of modest was conducted to determine if the change geographic area, comprising c. 800,000 km2 in climate between two 30-year periods in the U.S. and Canada. Despite its size, a (1946–1975 and 1976–2005) was sufficient strong northwest to southeast climatic to have affected wetland productivity. If so, gradient exists within the region; mean the analysis would provide evidence that annual temperature ranges from about trends for warming and drying projected 0–10°C and mean annual precipitation earlier for the mid 21st century (Johnson et from about 35–90 cm (Millett et al. 2009). al. 2005) may already have started in the late The intersection of these two climatic 20th century. The model indicated that gradients produces different sub-regional climate changes were sufficient to have climates, wetland functional dynamics and affected the wetland cover cycle, a major responsiveness to climatic change. Model indicator of wetland productivity quantified simulations using data from regional by a cover cycle index (Werner et al. 2013). weather stations with long-term records This analysis is the first to present evidence (≥ 100 years) show that the response of that climate change may already have wetlands to climate change will be highly affected wetland productivity in part of the variable geographically (Johnson et al. 2010). Prairie Pothole Region. The most favourable climate in the Prairie Climate changes that exceed ecological Pothole Region for wetland productivity thresholds can produce rapid and surprising during the 20th century is projected to shift changes in the functioning of natural eastward where there are fewer un-drained ecosystems (e.g. Holling 1973; CCSP 2009). wetland basins and much less grassland The most productive semi-permanent available as nesting habitat for waterfowl. prairie wetlands pass through three stages The naturally drier western edge of the during weather cycles: dry marsh, lake marsh Prairie Pothole Region, described as a and hemi-marsh (which includes both “boom or bust” region for waterfowl regenerating and degenerating sub-stages; production, may become largely a “bust” van der Valk & Davis 1978). Climatic should the future climate be more arid as thresholds associated with drought must be projected (Johnson et al. 2010). This possible reached and exceeded for habitats to enter future “mismatch” between the location of the dry marsh stage, as must those a productive wetland climate and functional associated with a precipitation deluge wetland basins stands as a current challenge needed to enter the lake marsh stage. for wetland managers as they develop future Between these two extremes, the most plans to allocate resources for wetland productive hemi-marsh stage is reached. conservation and management across the Ratios that produce the highest indices for Prairie Pothole Region. wetland productivity over decadal time The northwest portion of the Prairie intervals are approximately: 25:50:25 (dry, Pothole Region (west-) hemi and lake, respectively). Climate warmed and dried late in the 20th Century changes that cause wetlands to be “stuck” in (Millett et al. 2009). A hindcast simulation either the lake or dry marsh extremes stop

©Wildfowl & Wetlands Trust Wildfowl (2014) Special Issue 4: 343–367 354 Wetland issues affecting waterfowl vegetation cycling and decrease productivity. amendment to the 1934 “Duck Stamp Act” Because the majority of ducks produced in (legislative documents:16 U.S.C. 718-718j, 48 North America are reared in Prairie Pothole Stat.452; P.L. 85-585; 72 Stat. 486) (Loesch et Region wetlands, biologists are concerned al. 2012). The SWAP amendment authorised that wetlands responsible for past high rates that proceeds from the sale of duck stamps of waterfowl production could become and the import duties on ammunition and drier and fail in the future by never or rarely firearms should be used for the acquisition of reaching the lake marsh and hemi-marsh fee title (i.e. absolute ownership) or limited- stages of the cycle (Sorenson et al. 1998; interest title (restricted ownership) of Johnson et al. 2010). Waterfowl Production Areas, and also for Twenty years of modelling and field purchasing limited interest easements over research have found that prairie wetlands are Waterfowl Production Areas in Prairie highly sensitive to changes in climate and Pothole Region states (USFWS 2013). that they respond differently to wide- Over the past 50 years, the USFWS ranging sub-climates across the Prairie and its partners (e.g. sportsmen and Pothole Region. Moreover, they may already women, private landowners and non-profit have been negatively affected by climate conservation organisations) have acquired warming in the Canadian prairies, and may ownership of nearly 0.7 million ha in not reach water level thresholds under a National Wildlife Refuges and Waterfowl warmer climate needed to maintain historic Production Areas and easements over an dynamics and productivity. We suggest additional 1.1 million ha of Waterfowl development of an early warning system to Production Areas in the U.S. Prairie Pothole detect the onset of climate change across Region. The SWAP has thus acquired the Prairie Pothole Region by conducting easements to conserve a network of privately simulation modelling and field monitoring owned wetlands and grasslands which in tandem to provide further understanding provide nesting sites for breeding birds in of changes to date and to improve accuracy proximity to larger Waterfowl Production in predicting for future changes in Prairie Area wetland basins purchased for their Pothole Region wetlands. importance as brood-rearing habitat. During the first 35 years, habitat was acquired Prairie wetland conservation policy by USFWS biologists who applied Despite a changing climate and their knowledge of the area to prioritise anthropogenic denudation of large areas of acquisitions. More recently, spatially explicit the landscape, all is not lost in the Prairie habitat and biological data have been used to Pothole Region. To help protect critical develop statistical models used by the habitat for waterfowl, visionary waterfowl USFWS to assess the Prairie Pothole Region biologists and managers recognised the landscape (Stephens et al. 2008). Habitat importance of the region and initiated the conservation efforts are then focused toward USFWS’s Small Wetlands Acquisition areas that produce the greatest benefits for Program (SWAP) in 1958 with an migratory bird benefits, given the limited

©Wildfowl & Wetlands Trust Wildfowl (2014) Special Issue 4: 343–367 Wetland issues affecting waterfowl 355 conservation funds (Reynolds et al. 2006; be active in pursuing conservation goals Niemuth et al. 2008). in order to maintain North America’s In addition to traditional measures of waterfowl populations. Meeting existing conservation progress (e.g. money expended wetland and grassland conservation goals for land acquisitions and the number of is a daunting challenge (Doherty et al. acres protected), the success of the SWAP 2013). Only through collaborative and is assessed using measurable biological complementary efforts, which incorporate a outcomes such as the abundance of science-based approach to determining the waterfowl pairs and their breeding success. best places in the landscape for directing Through the purchase of wetland and conservation resources in the face of habitat grassland easements on private lands, the loss, will effective conservation of wetlands USFWS and its partners have secured in the Prairie Pothole Region be achieved. breeding habitat for an estimated 1.1 million waterfowl pairs across 13 species of Lower Great Lakes marshes waterfowl. The resultant effort contributes The lower Great Lakes coastal marshes are approximately 708,000 recruits annually for valuable areas for staging and wintering Mallard, Northern Pintail, A. waterfowl and are among the most strepera, Blue-winged Teal and Northern biologically significant wetlands within the Shoveler annually (Cowardin et al. 1995; Great Lakes region. These marshes have USFWS Habitat & Population Evaluation long been recognised for their importance in Team unpubl. data). While this large providing habitat for a wide variety of flora landscape-scale approach to waterfowl and fauna, and in particular for migratory conservation has been highly successful, an birds. As an example, the coastal wetlands of additional 3.8 million ha of grassland (88% northwest Ohio alone support c. 500,000 of the remaining grassland) and 0.7 million itinerant waterfowl during autumn migration ha of wetlands (75% of the remaining (Ohio Division of Wildlife, unpubl. data). wetlands) in the U.S. Prairie Pothole Region These marshes are also subject to a have been prioritised for protection great number of anthropogenic stressors, (Ringleman 2005). In 2012, land values including dredging, nutrient/pollutant averaged across the northern plains states loading, altered hydrological regimes and the from North Dakota to Kansas were introduction of non-native species. Today, a US$5,831/ha (USDA 2012) and, if applied majority of the region’s coastal marshes and to the 4.5 million-ha goals, would require wetlands have been drained or replaced by > US$2.6 trillion in fee-title acquisition costs. shoreline development or have been further Through various partnership efforts degraded by altered hydrology and sediment including the Migratory Bird Conservation deposition. Only 5% of the original 121,000 Fund, the Land and Water Conservation ha of Lake Erie marshes and swamps in Fund and funding under the North northwest Ohio remain (Bookhout et al. American Wetlands Conservation Act, 1989), and habitat loss continues to reduce the USFWS and its partners continue to the area available for diverse wetland plant

©Wildfowl & Wetlands Trust Wildfowl (2014) Special Issue 4: 343–367 356 Wetland issues affecting waterfowl communities capable of supporting wildlife are less well understood. For waterfowl populations. Habitat loss of this example, only a handful of studies have magnitude underscores the importance of shown the effects of Common Reed on maintaining the remaining habitat at the wildlife use and diversity, including studies highest level of quality possible. on turtles (Bolton & Brooks 2010), toads A wide variety of invasive species now (Greenberg & Green 2013), passerine birds dominate wetland flora in many lower Great (Meyer et al. 2010) and other wetland wildlife Lakes coastal marshes, having displaced (Schummer et al. 2012). In contrast, a native vegetation and in many cases substantial research base of Common Reed important waterfowl resources (Mills et al. biology, proliferation and management 1994; Zedler & Kercher 2004). In fact, exists in the form of peer-reviewed articles, invasive species are now considered the white papers and websites (e.g. http:// primary cause of wetland degradation in the www.greatlakesphragmites.net). Extensive region. The most abundant, widespread and research into chemical and biological harmful invasive plant species within these control measures for Purple Loosestrife wetlands include Common Reed Phragmites similarly led to the release of beetles australis, Reed Canary Grass Phalaris Galerucella sp. as a highly successful arundinacea, Curly Pondweed Potamogeton biological control during the 1990s, despite crispus, Eurasian Watermilfoil Myriophyllum a lack of data to show that the plant had spicatum, and non-native Cattail Typha negative impacts on the environment angustifolia and T. glauca. Other less (Hager & McCoy 1998; Treberg & Husband widespread but significant invasive species 1999). include European Frog-bit Hydrocharis While no single management strategy can morsus-ranae, Japanese Knotweed Polygonum be employed to treat infestations of these cuspidatum, Yellow Flag Iris Iris pseudacorus, diverse invasive plants, similarities do exist Purple Loosestrife Lythrum salicaria and among species. Most often, managers Water Chestnut Trapa natans. Invasive employ an Integrated Pest Management species outbreaks continue to occur in this (IPM) strategy that combines one or more region and relative newcomers such as techniques including mowing or harvesting, Flowering Rush Butomus umbellatus are smothering, drowning, herbicide treatments, quickly becoming established at nuisance biological control agents, controlled burns levels. and reseeding with native species In most cases, invasive plant species alter (Radosevich 2007; Holt 2009). With the the biotic and abiotic environment of exception of Purple Loosestrife, where wetlands by excluding native plants, biological control proved successful, the reducing plant diversity and modifying most effective and widely used strategies wetland processes (Drake et al. 1989; Davis typically include herbicide application within et al. 1999; Meyerson et al. 1999; Windham & the IPM strategy. As an example, the most Lathrop 1999; Rooth et al. 2003). However, effective control of Common Reed includes the indirect effects of invasive plants on a late-summer application of glyphosphate

©Wildfowl & Wetlands Trust Wildfowl (2014) Special Issue 4: 343–367 Wetland issues affecting waterfowl 357 herbicide followed by a spring burn or other management tools, implementing post- thatch removal method (J. Simpson, unpubl. treatment monitoring and research, and data; MDEQ 2008). Variations of this organising and educating landowners. method have also been applied effectively Invasive wetland plants are widespread for many other emergent invasive plants. and continually establishing across coastal Other aquatic-approved herbicides, such and inland wetlands within the Great Lakes as those formulated with imazypyr, are region. Management of invasive plants is equally effective at removing invasive plants, unavoidable in order to continue providing but residual action limits subsequent quality wetland habitat for waterfowl regeneration of native species. Submerged and other wetland-dependent species. or floating-leaved vegetation is typically Management strategies continue to be managed with granular or similar broadcast refined, tested and researched, but research herbicides in conjunction with mechanical into the biological implications of these mowing or harvesting. Ironically, some species should continue. Up-front research success has been also demonstrated by using demonstrating the negative impacts of these non-native Common Carp Cyprinus carpio to species is essential for prioritising their reduce monocultures of submersed invasive management and focusing effort on species plants (Kroll 2006), but carp often become of greatest concern. Additionally, a greater established and can remove desirable native understanding of the indirect effects of vegetation (Bajer et al. 2009). these plant species on waterfowl and In response to the logistical and financial other wetland-dependent wildlife is required hurdles associated with managing large to avoid expending exhaustive control non-native plant invasions, stakeholders measures on species whose ecological in the Great Lakes Region of the U.S. and consequences are unproven. elsewhere have united to form cooperative weed management areas. These diverse Central Valley of California groups now exist in most Great Lakes The Central Valley of California supports an states and provinces and represent a cross average of about 5.5 million wintering section of government agencies, local units waterfowl annually, making it one of the of government, non-profit conservation most important regions for waterfowl in groups, community associations and North America. However, the Central Valley individual landowners. In many cases, these has lost approximately 95% of its original associations form to address ecological, wetlands due to flood control, urbanisation social and economic problems linked to and conversion to agriculture (Fleskes 2012). vegetation management along developed During the past 20 years, conservation shorelines and within recreational sites. programmes such as the Wetlands Reserve Using private and government grant funds, Program, the North American Wetlands these cooperative weed management areas Conservation Act, the Migratory Bird have made progress by identifying and Conservation Fund and the state’s Inland prioritising treatment sites, providing Wetlands Conservation Program have

©Wildfowl & Wetlands Trust Wildfowl (2014) Special Issue 4: 343–367 358 Wetland issues affecting waterfowl provided a means to protect, enhance or of contaminants and require expensive restore former and existing wetlands monitoring programmes to demonstrate throughout the Central Valley. Additionally, compliance. Additionally, wetlands and intensive management of remaining wetlands flooded rice fields are ideal environments for food production, along with flooded for methylation of mercury – the form of grain (especially rice), has helped to mitigate mercury which readily bioaccumulates and for wetland loss and allowed continued is toxic to humans and wildlife (Ackerman support of large numbers of waterfowl. & Eagles-Smith 2010). Mercury is a While partners of the Central Valley Joint legacy contaminant from the gold rush of Venture have made considerable progress the 1800s and is widespread throughout towards habitat goals of the North northern Central Valley watersheds. American Waterfowl Management Plan, Regulations restricting methylmercury changing policies and demand for limited discharge into the San Joaquin-Sacramento resources, such as water, hinders Delta may inhibit wetland restoration and management of existing wetlands and management and discourage flooding of could impair farming practices that benefit rice fields during autumn and winter. nesting and wintering waterfowl. Water Ongoing conservation planning efforts in supply for certain National Wildlife Refuges the Sacramento-San Joaquin Delta region of and State Wildlife Areas, as well as other the Central Valley emphasise the restoration wetland complexes, was required under of anadromous fish runs (e.g. salmon Salmo the provisions of the 1992 Central Valley and Oncorhynchus sp.) and other endangered Project Improvement Act. However, the full fish (e.g. Delta Smelt Hypomesus transpacificus), allocation of water required under the Act possibly at the expense of waterfowl habitat. has been achieved only once in the past 20 For example, proposed breaching of levees years (G. Yarris, pers. comm.). In-stream of some managed wetlands in the Suisun flow requirements for fish species protected Marsh to restore tidal action and provide under various state and federal plans are fish habitat will reduce managed wetlands competing pressures on the water available in the region and require the restoration for wetland management, such as winter- or creation of new managed wetlands flooding of rice fields, in the Central Valley. elsewhere to compensate for this loss. The Moreover, the Clean Water Act, which use of tidal wetlands by dabbling ducks is protects wetland resources throughout the low compared to managed wetlands (Coates United States, increases management et al. 2012). Thus, tidal restoration may complexity in certain situations. Because of reduce the waterfowl carrying capacity of the altered hydrology of the Central Valley, the Suisun Marsh, decreasing its importance most wetlands are managed with controlled for ducks in the Pacific Flyway. flooding and drainage and thus are subject Another recent constraint to wetland to the same regulations as other water management is the mosquito abatement diverters and dischargers. Current or policies of vector control districts. Because proposed regulations will limit the discharge many wetlands in California are near urban

©Wildfowl & Wetlands Trust Wildfowl (2014) Special Issue 4: 343–367 Wetland issues affecting waterfowl 359 areas, summer irrigation for waterfowl food likely coming to a close. Secondly, the fate of plant production, early autumn flooding for large scale wetland conservation lies with shorebird migration and other management private landowners – public land and areas activities that may produce mosquitoes are protected by conservation easements will discouraged. Although alternative wetland likely not sustain the current breeding management strategies are being developed populations of waterfowl in most of North in some cases (Washburn 2012), costs America. Thirdly, wetland conservation associated with mosquito control have policies and objectives must be robust to the created a disincentive to implement wetland wide variety of political, societal and management practices on both public and environmental shifts or vagaries. One private wetlands (Olson 2010). For example, such environmental factor important to mosquito control costs have tripled on State conservation priorities is changing climate, Wildlife Areas since concerns of public where simulations have shown potential exposure to West Nile Virus have come to changes in waterbird productivity and the fore (B. Burkholder, pers. comm.). impacts on wetland availability when certain Constraints, restrictions and regulations climate thresholds are exceeded. Fourthly, on wetlands and flooded agriculture in the increasing demand for water due to urban Central Valley likely will continue into the and population growth, irrigated agriculture, future as the demand for water increases. and other commercial uses (e.g. hydraulic Creative solutions to wetland restoration fracturing) combined with expected impacts and management, and especially increased of climate change will increase competition participation in policy development, will for and cost of water for managed wetlands be critical for advancing the goals of and waterfowl habitats. Fifthly, increased the Central Valley Joint Venture and wetland drainage for agriculture followed ensuring that sufficient habitat exists for all by increased crop irrigation increases wetland-dependent species in the Pacific water requirements while reducing the Flyway. opportunities for aquifer recharge. Sixthly, updating and improving existing data on Looking ahead wetland distribution and quality for waterfowl is needed but will be difficult Challenges given declining government budgets and During our session, a number of key points changes in agency priorities. Overall, and challenges to wetland conservation and managing waterfowl populations and their waterfowl management became apparent. associated habitats in the face of climate Firstly, unless there is an immediate and change, invasive species and other biotic significant change in a) wetland protection stressors will be challenging. measures, and b) agricultural policies that provide a disincentive to wetland drainage Opportunities and conversion, the recent “good old days” In spite of these challenges, there are also a of abundant wetlands for waterfowl are number of opportunities in the near future

©Wildfowl & Wetlands Trust Wildfowl (2014) Special Issue 4: 343–367 360 Wetland issues affecting waterfowl that may directly or indirectly affect wetland and, in some cases, potential function for and waterfowl conservation. wetland restoration sites. For each function, wetlands providing the function at high or National wetlands inventory moderate levels are predicted based on Strategic conservation is critical to achieve certain properties included in the database. significant progress towards wetland Correlations between database features and conservation goals (Stephens et al. 2008) and functions were developed first by consulting accurate information on the location, type the literature and then by peer review and status and trends of wetlands is vital to from regional scientists. For provision of this effort. In 1974, the USFWS established waterfowl and waterbird habitat, in addition the National Wetlands Inventory Program to the high and moderate categories, a third (NWI) to provide information on the category for Wood Duck Aix sponsa habitat location, distribution and characteristics of was created because this species frequents U.S. wetlands. By late 2014, the NWI is wooded swamps along rivers and streams as expected to be complete for the lower 48 opposed to more open water wetlands (e.g. states, yet by that time much of the data marshes) occupied by most other waterfowl will be > 25 years old. While NWI maps and waterbirds. NWI+ data and the results and geospatial data showing wetland of NWI+ analyses are displayed via an types (Cowardin et al. 1979) have helped online map (NWI+ web mapper at promote wetland conservation, continual http://aswm.org/wetland-science/wetlands- updating and additional information (e.g. one-stop-mapping); NWI+ reports are also hydrogeomorphic properties) is needed to posted. This tool provides users with a first use NWI data for predicting wetland approximation of wetland functions across functions and determining more readily their large geographic areas. To date, such data value to organisms of interest (e.g. waterfowl). are available or will soon be posted for five Recognising this need, the USFWS recently entire states (CT, DE, MA, NJ and RI) while developed descriptors for landscape position, pilot or special projects are completed or are landform, water flow path and waterbody in progress for parts of other states (AK, type (LLWW descriptors; Tiner 2003, 2011) CA, MD, MS, NH, NY, PA, SC, TX, VA, VT to supplement NWI data on a case-by-case and WY). basis. When the Federal Geographic Data The NWI+ data provide a better Committee established its wetland mapping characterisation of wetlands, an expanded standard (FGDCWS 2009) for the federal geospatial database and a preliminary government, it suggested adding these landscape-level assessment of wetland attributes to increase the functionality of the functions. This information is valuable to NWI database. fish and wildlife biologists, conservation When LLWW descriptors are added to planners, ecosystem modellers, regulatory existing NWI data, a “NWI+ database” is personnel and the general public. Limited created. The NWI+ database is used to NWI funds do not allow these data to be predict 11 functions of existing wetlands produced nationwide, so NWI+ data are

©Wildfowl & Wetlands Trust Wildfowl (2014) Special Issue 4: 343–367 Wetland issues affecting waterfowl 361 project area-focused. With further budget should nonetheless have input to reductions imminent, such data, as well discussions regarding the anticipated effects as updated traditional NWI data, will of new and ongoing policies on wetlands. likely come mainly from user-funded initiatives. Other agencies/organisations Acknowledgements have produced or are producing NWI+ data We thank more than 100 wetland and for parts of many states (MI, MN, MT, NM, waterfowl professionals for participating in OR, WI), while some states (CT, DE, NY, our special session and the thousands of and PA) have funded NWI+ work in their conservationists who work daily to restore state. NWI+ data will provide new and protect wetlands for waterfowl opportunities for assessing and assigning throughout the world. We thank our functional values to wetlands at the time that Associate Editor L. Webb and Editor E. they are mapped, and have the potential to Rees for helpful comments which improved increase the efficiency of conservation this manuscript. Results, conclusions and planning for target species or groups (e.g. opinions stated in this paper do not dabbling ducks, wood ducks). necessarily represent the views of the Influencing policy USFWS, The Wildlife Society or other state and federal agencies. Scientists, wetland managers and other conservationists should not simply react to References policy shifts that influence wetland loss, but must also work to influence them. There are Ackerman, J.T. & Eagles-Smith, C.A. 2010. many opportunities to incorporate science Agricultural wetlands as potential hotspots for mercury bioaccumulation: Experimental into the policy debates that are shaping evidence using caged fish. Environmental the future of waterfowl management. Science and Technology 44: 1451–1457. Waterfowl scientists and managers can, and Baar, L., Matlack, R.S., Johnson, W.P. & Barron, must, focus increased efforts on providing R.B. 2008. Migration chronology of information that can influence the future of waterfowl in the Southern High Plains of wetland conservation policies, such as the Texas. Waterbirds 31: 394–401. Clean Water Act, that hold in the balance the Baldassarre, G.A. & Bolen, E.G. 2006. Waterfowl future of tens of millions of acres of Ecology and Management, 2nd edition. Kreiger waterfowl habitat. Moreover, waterfowl Publishing, Malabar, Florida, USA. conservationists should engage private Bajer, P.G., Sullivan, G. & Sorenson, P.W. 2009. landowners and convey to them the Effects of rapidly increasing population of importance of wetlands for waterfowl as common carp on vegetative cover and waterfowl in a recently restored midwestern well as the myriad of other functions and shallow lake. Hydrobiologia 632: 235–245. benefits that these habitats provide for Bartuszevige, A.M., Pavlacky, D.C., Jr., Burris, L. society. Although government restrictions & Herbener, K. 2012. Inundation of playa on advocacy can limit the participation of wetlands in the western Great Plains relative many scientists in policy debates, experts to landcover context. Wetlands 32: 1103–1113.

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Bergan, J.F. & Smith, L.M. 1993. Survival rates of Dahl, T. E. 2000. Status and Trends of Wetlands in female wintering in the Playa Lakes the Conterminous United States 1986 to 1997. Region. Journal of Wildlife Management 57: U.S. Department of the Interior, U.S. Fish 570–577. and Wildlife Service, Washington D.C., Bolton, R.M. & Brooks, R.J. 2010. Impact of the USA. seasonal invasion of Phragmites australis Dahl, T. E. 2006. Status and Trends of Wetlands in (common reed) on turtle reproductive the Conterminous United States 1998 to 2004. success. Chelonian Conservation and Biology 9: U.S. Department of the Interior, Fish and 238–243. Wildlife Service, Washington D.C., USA Bonan, G.B. 2008. Forests and climate change: Dahl, T. E. 2011. Status and Trends of Wetlands in forcings, feedbacks, and the climate benefits the Conterminous United States 2004 to 2009. of forests. Science 13: 1444–1449. U.S. Department of the Interior, Fish and Bookhout, T.A., Bednarik, K.E. & Kroll, R.W. Wildlife Service, Washington D.C., USA. 1989. The Great Lakes marshes. In L.M. Dahl, T. E. & Johnson, C.E. 1991. Status and Trends Smith, R.L. Pederson & R.M. Kaminski of Wetlands in the Conterminous United States, (eds.), Habitat Management for Migrating mid-1970s to mid-1980s. U.S. Department of and Wintering Waterfowl in North America, the Interior, Fish and Wildlife Service, pp. 131–156. Texas Tech University Press, Washington D.C., USA. Lubbock, Texas, USA. Davis, M.A. 2009. Invasion Biology. Oxford Bradshaw, C.J.A., Warkentin, I.G. & Sodhi, N.S. University Press, Oxford, UK. 2009. Urgent preservation of boreal carbon Doherty, K.E., Ryba, A.J., Stemler C.L., Niemuth, stocks and biodiversity. Trends in Ecology and N.D. & Meeks, W.A. 2013. Conservation Evolution 24: 541–548. planning in an era of change: state of the U.S. Cariveau, A.B., Pavlacky, D.C., Bishop, A.A. Prairie Pothole Region. Wildlife Society Bulletin & LaGrange, T.G. 2011. Effects of 37: 546–563. surrounding land use on playa inundation Drake, J.A., Mooney, H.A., Di Castri, F., Groves, following intense rainfall. Wetlands 31: 65–73. R.H., Kruger, F.J., Rejmánek, M. & Coates, P.S., Casazza, M.L., Halstead, B.J. & Williamson, M. 1989. Biological Invasions: a Fleskes, J.P. 2012. Relative value of managed Global Perspective. Wiley, Chichester, UK. wetlands and tidal marshlands for wintering Federal Geographic Data Committee Wetlands northern pintails. Journal of Fish and Wildlife Subcommittee (FGDCWS). 2009. Wetlands Management 3: 98–109. Mapping Standard. FGDC Document Number Cowardin, L.M., Carter, V., Golet, F.C. & LaRoe, FGDC-STD-015-2009. U.S. Fish and E.T. 1979. Classification of Wetlands and Wildlife Service, Washington D.C., USA. Deepwater Habitats of the United States. Report Fleskes, J.P. 2012. Wetlands of the Central Valley FWS/OBS-79/31. U.S. Fish and Wildlife of California and Klamath Basin. In D. Service, Washington D.C., USA. Batzer & A. Baldwin (eds.), Wetland Habitats Cowardin, L.M., Shaffer T.L. & Arnold, P.M. of North America: Ecology and Conservation 1995. Evaluations of Duck Habitat and Concerns, pp. 357–370. University of Estimation of Duck Population Sizes with California Press, Berkeley, California, USA. a Remote-Sensing-Based Approach. Biological Frayer, W.E., Monahan, T.J., Bowden, D.C. & Science Report No. 2. U.S. Department of Graybill, F.A. 1983. Status and Trends of Wetlands the Interior, Washington D.C., USA. and Deepwater Habitats in the Conterminous

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United States, 1950s to 1970s. Colorado State hydric soils on the Southern High Plains. University, Fort Collins, Colorado, USA. Wetlands 31: 483–492. Greenberg, D.A., & Green, D.M. 2013. Effects of Johnson, L.A., Haukos, D.A., Smith, L.M. & invasive plant on population dynamics in McMurry, S.T. 2012. Physical loss and toads. Conservation Biology 27: 1049–1057. modification of Southern Great Plains Hager, H.A. & McCoy, K.D. 1998. The playas. Journal of Environmental Management implications of accepting untested hypotheses: 112: 275–283. A review of the effects of purple loosestrife Johnson, W.C., Millett, B.V., Gilmanov, T., (Lythrum salicaria) in North America. Biodiversity Voldseth, R.A., Guntenspergen, G.R. & and Conservation 7: 1069–1079. Naugle, D.E. 2005. Vulnerability of northern Haukos, D.A. 2008. Analyses of Selected Midwinter prairie wetlands to climate change. Bioscience Waterfowl Data (1955–2008) in Region 2 (Central 25: 863–872. Flyway Portion). U.S. Fish and Wildlife Service, Johnson, W.C., Werner, B., Guntenspergen, G.R., Regional Migratory Bird Office, Albuquerque, Voldseth, R.A., Millett, B., Naugle, D.E., New Mexico, USA. Tulbure, M., Carroll, R.W.H., Tracy, J. & Haukos, D.A. & Smith, L.M. 1994. Importance Olawsky, C. 2010. Prairie wetland complexes of playa wetlands to biodiversity of the as landscape functional units in a changing Southern High Plains. Landscape and Urban climate. Bioscience 60: 128–140. Planning 28: 83–98. Johnston, C.A. 2013. Wetland losses due to row Haukos, D.A. & Smith, L.M. 2003. Past and crop expansion in the Dakota Prairie Pothole future impacts of wetland regulations on Region. Wetlands 33: 175–182. playas. Wetlands 23: 577–589. Kantrud, H.A. & Stewart, R.E. 1977. Use of Holling, C.S. 1973. Resilience and stability of natural basin wetlands by breeding waterfowl ecological systems. Annual Review of Ecology in North Dakota. Journal of Wildlife Management and Systematics 4: 1–23. 41: 243–253. Holt, J.S. 2009. Management of invasive terrestrial Kroll, R.W. 2006. Status of Winous Point marsh, plants. In M.N. Clout & P.A. Williams (eds.), fall 2006. Unpublished report to the Winous Invasive Species Management: A Handbook of Point Marsh Conservancy, Port Clinton, Principles and Techniques, pp. 126–139. Oxford Ohio, USA. University Press, Oxford, UK. Loesch, C.R., Reynolds, R.E. & Hanson, L.T. Johnson, L. 2011. Occurrence, function and 2012. An assessment of re-directing breeding conservation of playa wetlands: the key to waterfowl conservation relative to predictions biodiversity of the Southern Great Plains. of climate change. Journal of Fish and Wildlife Ph.D. thesis, Texas Tech University, Management 3: 1–22. Lubbock, Texas, USA. Luo, H.R., Smith, L.M., Allen, B.L. & Haukos, Johnson, W.P, Rice, M.B., Haukos, D.A. & D.A. 1997. Effects of sedimentation on playa Thorpe, P. 2011a. Factors influencing the wetland volume. Ecological Applications 7: occurrence of inundated playa wetlands 247–252. during winter on the Texas High Plains. Mattson, B.J., Runge, M.C., Devries, J.H., Boomer, Wetlands 31: 1287–1296. G.S., Eadie, J.M., Haukos, D.A., Fleskes, J. P., Johnson, L.A., Haukos, D.A., Smith, L.M. & Koons, D.N., Thogmartin, W.E. & Clark, R.J. McMurry, S.T. 2011b. Jurisdictional loss of 2012. A prototypical modeling framework for playa wetlands caused by reclassification of integrated harvest and habitat management of

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North American waterfowl: case-study of Niemuth N.D., Reynolds, R.E., Granfors, D.A., northern pintail metapopulation dynamics. Johnson, R.R., Wangler, B. & Estey, M.E. Ecological Modeling 225: 146–158. 2008. Landscape-level planning for Meyer, S.W., Badzinski, S.S., Petrie, S.A. & conservation of wetland birds in the U.S. Ankney, C.D. 2010. Seasonal abundance and Prairie Pothole Region. In J.J. Millspaugh & species richness of birds in common reed F.R. Thompson (eds.), Models for Planning habitats in Lake Erie. Journal of Wildlife Wildlife Conservation in Large Landscapes, pp. Management 74: 1559–1567. 533–560. Elsevier Science, Burlington Meyerson, L.A., Chambers, R.M. & Vogt, Massachusetts, USA. K.A. 1999. The effects of Phragmites O’Connell, J.L., Johnson, L.A. Smith, L.M., removal on nutrient pools in a freshwater McMurry, S.T. & Haukos, D.A. 2012. tidal marsh ecosystem. Biological Invasions 1: Influence of land-use and conservation 129–136. programs on wetland plant communities of Mitsch, W.J. & Gosselink, J.G. 2007. Wetlands. 4th the semi-arid United States Great Plains. edition. John Wiley & Sons, Inc., New York, Biological Conservation 146: 108–115. USA. Olson, B.W. 2010. An experimental evaluation of Moon, J.A. & Haukos, D.A. 2006. Survival of cost effective moist-soil management in the female northern pintails wintering in the Sacramento Valley of California. M.Sc. Playa Lakes Region of northwestern Texas. thesis. University of California, Davis, Journal of Wildlife Management 70: 777–783. California, USA. Moon, J.A., Haukos, D.A. & Smith, L.M. 2007. Pew Environmental Group (PEG). 2011. A Changes in body condition of pintails Forest of Blue: Canada’s Boreal. Seattle, wintering in the Playa Lakes Region. Journal of Washington, USA. PEG unpublished report. Wildlife Management 71: 218–221. PEG, Seattle, Washington, USA. Accessible Michigan Department of Environmental Quality at http://borealscience.org/wp-content/ (MDEQ). 2008. A Guide to the Control and uploads/2012/06/report-forestofblue.pdf Management of Invasive Phragmites, 2nd edition. (last accessed 8 February 2014). Lansing, Michigan, USA. Poiani, K.A. & Johnson, W.C. 1991. Global Millar, J.B. 1989. Perspectives on the status of warming and prairie wetlands. Bioscience 41: Canadian prairie wetlands. Freshwater Wetlands 611–618. and Wildlife 61: 821–852. Poiani, K.A., Johnson, W.C. & Kittel, T.G.F. Millett, B.V., Johnson, W.C. & Guntenspergen, 1995. Sensitivity of a prairie wetland to G.R. 2009. Climate trends of the North increased temperature and seasonal American Prairie Pothole Region. Climatic precipitation changes. Water Resources Bulletin Change 93: 243–267. 31: 283–294. Mills, E.L., Leach, L.H., Carlton, J.T. & Secor, Poiani, K.A., Johnson, W.C., Swanson, G.A. C.L. 1994. Exotic species and the integrity of & Winter, T.C. 1996. Climate change and the Great Lakes. Bioscience 44: 666–676. northern prairie wetlands: simulations Nichols, J.D., Runge, M.C., Johnson, F.A. of long-term dynamics. Limnology and & Williams, B.K. 2007. Adaptive harvest Oceanography 41: 871–881. management of North American populations: Poiani, K.A. & Johnson, W.C. 2003. Simulation of a brief history and future prospects. Journal of hydrology and vegetation dynamics of prairie Ornithology 148: S343–S349. wetlands in the Cottonwood Lake Area. In

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T.C. Winter (ed.), Hydrological, Chemical and wetland conservation in Canada. Technical Biological Characteristics of a Prairie Pothole Consultation on Designing Methodologies Wetland Complex under Highly Variable Climatic to Review Laws and Institutions Relevant to Conditions – the Cottonwood Lake Area, East- Wetlands. Environment Canada unpublished Central North Dakota, pp. 95–109 U.S. report. Environment Canada, Ottawa, Geological Survey Professional Paper No. Ontario, Canada. Accessible at http:// 1675. U.S. Geological Survey, Denver, www.ramsar.org/doc/wurc/wurchbk3cs2.doc Colorado, USA. Accessible at http:// (last accessed 8 April 2014). pubs.er.usgs.gov/publication/pp1675 (last Schummer, M.L., Palframan, J., McNaughton, E., accessed 4 August 2014). Barney, T. & Petrie, S.A. 2012. Comparisons Radosevich, S.R., Holt, J.S. & Ghersa, C.M. 2007. of bird, aquatic macroinvertebrate, and plant Ecology of Weeds and Invasive Plants: Relationship communities among dredged ponds and to Agriculture and Natural Resource Management. natural wetlands habitats at Long Point, Lake John Wiley and Sons, Inc. Hoboken, New Erie, Ontario. Wetlands 32: 945–953. Jersey, USA. Slattery, S.M., Morissette, J.L., Mack, G.G. Ray, J.D., Sullivan, B.D. & Miller, H.W. 2003. & Butterworth, E.W. 2011. Waterfowl Breeding ducks and their habitats in the High conservation planning: science needs and Plains of Texas. Southwestern Naturalist 48: approaches. In J.V. Wells (ed.), Boreal Birds of 241–248. North America: a Hemispheric View of their Reynolds, R. E., Shaffer, T.L., Loesch, C.R. & Conservation Links and Significance, pp. 23– Cox, R.R. 2006. The Farm Bill and duck 40. University of California Press, Berkeley, production in the Prairie Pothole Region: USA. increasing the benefits. Wildlife Society Bulletin Smerdon, B.D., Devito, K.J. & Mendoza, C.A. 34: 963–974. 2005. Interaction of ground water and Ringelman, J.K. (ed.) 2005. Prairie Pothole Joint shallow lakes on outwash sediments in the Venture 2005 implementation plan. U.S. sub-humid Boreal Plains of Canada. Journal of Fish and Wildlife Service, Denver, Colorado, Hydrology 314: 246–262. USA. Smith, A.G., Stoudt, J.H. & Gollop, J.B. 1964. Riordan, B., Verbyla, D. & McGuive, A.A. 2006. Prairie potholes and marshes. In J. Linduska Shrinking ponds in subarctic Alaska based on (ed.), Waterfowl Tomorrow, pp. 39–50. U.S. 1950–2002 remotely sensed images. Journal of Government Printing Office, Washington Geophysical Research 111: 1–11. D.C., USA. Roach, J., Griffith, B., Verbyla, D. & Jones, J. Smith, L.C., Sheng, Y., MacDonald, G.M. & 2011. Mechanisms influencing changes in Hinzman, L.D. 2005. Disappearing lake area in Alaskan boreal forest. Global lakes. Science 308: 1429. Change Biology 17: 2576–2583. Smith, L.M. 2003. Playas of the Great Plains. Rooth, J.E., Stevenson, J.C. & Cornwell, J.C. University of Texas Press, Austin, USA. 2003. Increased sediment accretion rates Smith, L.M., Haukos, D.A., McMurry, S.T., following invasion by Phragmites australis: LaGrange, T. & Willis, D. 2011. Ecosystem the role of litter. Estuaries and Coasts 26: services provided by playa wetlands in the 475–483. High Plains: potential influences of USDA Rubec, C. & Lynch-Stewart, P. 1998. Regulatory conservation programs and practices. and non-regulatory approaches for Ecological Applications 21: S82–S92.

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Smith, L.M., Haukos, D.A. & McMurry, S. 2012. Tiner, R.W. 2011. Dichotomous keys and mapping High Plains Playas. In D. Batzer & A. codes for wetland landscape position, landform, water Baldwin (eds.), Wetland Habitats of North flow path, and waterbody type descriptors: Version America: Ecology and Conservation Concerns, pp. 2.0. U.S. Fish and Wildlife Service, National 299–311. University of California Press, Wetlands Inventory Program, Northeast Berkeley, USA. Region, Hadley, Massachusetts, USA. Soja, A.J., Tchebakova, N.M., French, N.H.F., Treberg, M.A. & Husband, B.C. 1999. Flannigan, M.D., Shugart, H.H., Stocks, B.J., Relationship between the abundance of Sukhinin, A.I., Parfenova, E.I., Chappin, F.S., Lythrum salicaria (purple loosestrife) and plant III & Stackhouse, P.W., Jr. 2007. Climate- species richness along the Bar River, Canada. induced boreal forest change: Predictions Wetlands 19: 118–125. verses current observation. Global and Tsai, J.S., Venne, L.S., McMurry, S.T. & Smith, Planetary Change 56: 274–296. L.M. 2007. Influences of land use and Sorenson, L.G., Goldberg, R., Root, T.L. & wetland characteristics on water loss rates Anderson, M.G. 1998. Potential effects of and hydroperiods of playas in the Southern global warming on waterfowl populations High Plains, USA. Wetlands 27: 683–692. breeding in the northern Great Plains. van der Valk, A. G. & Davis, C.B. 1978. The role Climatic Change 40: 343–369. of seed banks in the vegetation dynamics Stephens, S.E., Walker, J.A., Blunck, D.R., of prairie glacial marshes. Ecology 59: 332– Jayaraman, A., Naugle, D.E., Ringelman, J.K. 335. & Smith, A.J. 2008. Predicting risk of habitat Vrtiska, M.P., Gammonley, J.H., Naylor, L.W., & conversion in native temperate grasslands. Raedeke, A.H. 2013. Economic and Conservation Biology 22: 1320–1330. conservation ramifications from the decline Stewart, R.E. & Kantrud, H.A. 1971. Classification of waterfowl hunters. Wildlife Society Bulletin of natural ponds and lakes in the glaciated prairie 37: 380–388. region. U.S. Fish and Wildlife Service Resource Washburn, N.B. 2012. Experimental evaluation Publication 92. U.S. Fish and Wildlife of tradeoffs in mosquito production and Service, Washington D.C., USA. waterfowl food production in moist-soil Stocker, T.F., Qin, D., Plattner, G.K., Tignor, habitats of California’s Central Valley. M.Sc. M., Allen, S.K., Boschung, J., Nauels, A., thesis. University of California, Davis, Xia, Y., Bex, V. & Midgley, P.M. (eds.) California, USA. 2013. Climate Change 2013: The Physical Science Weller, M.W. & Fredrickson, L.H. 1974. Avian Basis. Contribution of Working Group I ecology of a managed glacial marsh. Living to the Fifth Assessment Report of the Bird 12: 269–291. Intergovernmental Panel on Climate Change. Wells, J.V. 2011. Boreal forest threats and Cambridge University Press, Cambridge, conservation status. In J.V. Wells (ed.), Boreal UK. birds of North America: a Hemispheric View of Tiner, R.W. 2003. Correlating enhanced National their Conservation Links and Significance, pp. 1–6. Wetlands Inventory data with wetland functions for University of California Press, Berkeley, watershed assessments: a rationale for northeastern USA. U.S. wetlands. U.S. Fish and Wildlife Service, Wells, J.V. & Blancher, P.J. 2011. Global role for National Wetlands Inventory Program, sustaining bird populations. In J.V. Wells Region 5, Hadley, Massachusetts, USA. (ed.), Boreal birds of North America: a

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Photograph: Mallard and Northern Pintail in a seasonal emergent wetland in the Illinois River Valley, Illinois, USA, by Heath Hagy.

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