by Tina Yerkes, Ph.D.
The Great Lakes contain 20 percent of the world’s fresh water, sustain an economy for 30 million people, and support millions of waterfowl throughout their annual cycle. This massive watershed drains 201,000 square miles and has over 10,000 miles of shoreline, which is more than the Atlantic and Pacific coasts combined.
Composed of six interconnected lakes, the Great Lakes are important for drinking water, sport and commercial fishing, waterfowl hunting, and other recreational activities. Some of the oldest hunting clubs in the United States and Canada are found along the shores of the Great Lakes, where waterfowlers still pursue mallards, black ducks, canvasbacks, and lesser scaup.
Conserving the region’s waterfowl habitat is wrought with challenges, including invasive species, expanding human populations, continued loss and degradation of habitat, and the effects of climate change. Nonnative species, such as the zebra mussel and purple loosestrife, are disrupting food webs and causing billions of dollars in damage to infrastructure and fisheries.
Birds that eat zebra mussels, which are filter feeders, ingest heavy metals and other toxins. Phragmites (common reed) and purple loosestrife displace native plants that provide nesting cover and food for waterfowl and other wetland species. Biologists have documented at least 185 invasive species in the Great Lakes system, and a new one is introduced every month.
The Great Lakes watershed has lost 62 percent of its original wetlands, and some parts of this region have lost more than 90 percent of these habitats. Such extensive losses have created a highly fragmented landscape. Unfortunately, the most critical challenge for Great Lakes waterfowl is the continued destruction and degradation of habitat, including the coastal and inland wetlands and river corridors the birds depend on. Habitat loss in the region results from a combination of urban expansion and changing agricultural practices. Despite laws and regulations intended to protect wetlands, the Great Lakes watershed continues to experience losses of small, seasonally flooded wetlands, which are critically important for waterfowl.
Because of the varied challenges, multiple uses, and human influences in the watershed, DU’s conservation programs focus on sustaining migrating, wintering, and breeding waterfowl through direct habitat programs, science, and policy actions. For example, recent research in Canada and the United States directed DU to focus on wetland restoration for mallards breeding in the Great Lakes region, rather than nesting habitat, which is less of a concern than on the prairies. Additionally, DU is undertaking a landscape-level study of spring migrants to determine the resource needs of a variety of species in order to define future habitat initiatives.
DU’s public policy work has the potential to affect the broad landscape of the Great Lakes, including improving wetland protection laws and securing funding for local restoration efforts. The recently reauthorized Great Lakes Fish and Wildlife Restoration Act (GLFWRA) doubled funding for fish and wildlife restoration grants from $8 million to $16 million.
“Ducks Unlimited played a pivotal role in securing reauthorization of GLFWRA,” said Robyn Thorson, regional director of the U.S. Fish and Wildlife Service’s Great Lakes/Big Rivers region. “DU’s expertise and partnerships on Capitol Hill, DU’s testimony to Congress, and the voices of DU’s membership in the Midwest reinforced the need to expand the act. We are all indebted to DU’s great work on this issue.”
DU’s research and policy efforts augment direct habitat programs in the Great Lakes. These programs focus on areas where DU can have the biggest impact on waterfowl populations: the watersheds of Lake Erie, the St. Lawrence River, Saginaw Bay, southwest Michigan, and eastern Wisconsin. The majority of DU’s habitat programs focus on breeding and spring staging waterfowl, while some work targets wintering ducks.
The most common breeding waterfowl in the Great Lakes region include mallards, blue-winged teal, wood ducks, ring-necked ducks, and Canada geese. DU programs focus primarily on mallards and blue-winged teal, because these populations have experienced declines in the Great Lakes states. The major limiting factor for breeding mallards in the Great Lakes is duckling survival, so DU’s programs focus on providing brood-rearing habitat through wetland restoration and protection.
In spring, the Great Lakes region is a significant staging area for many waterfowl, including mallards, teal, gadwalls, pintails, canvasbacks, scaup, tundra swans, and Canada geese. Providing inland and coastal marsh systems that ensure food and cover for staging waterfowl is critical, especially during the spring when food resources are limited. Habitat programs are currently delivered under the assumption that small wetland restoration will address the nutritional needs of spring migrants, but DU is testing this assumption because there is uncertainty about food resource availability and habitat use during this period.
The third aspect of DU’s Great Lakes habitat program involves water quality in the lakes, because waterfowl rely heavily on coastal marshes and open-water habitat for wintering and fall migration. Soil erosion, sedimentation, nutrient loading, and contamination from intensive agriculture practices, construction, and development are the main sources of degraded water quality in this area. Watershed conservation activities such as wetland and vegetation buffer zone restoration improve the quality and quantity of habitat available to waterfowl. This is important for wintering and staging waterfowl that use coastal bays and marshes where food resources are significantly affected by poor water quality. Habitat programs that address water quality target wetland restoration in coastal zones and tributaries that feed the lakes.
The Great Lakes watershed is a priority area for Ducks Unlimited and for several other state, federal, and nonprofit entities. Working collaboratively, DU has been able to conserve important habitat in this region, but there is much left to be done to stay ahead of the pressures from the growing human population, continued introduction and expansion of invasive species, and the threat of global warming. DU will continue to aggressively deliver conservation programs in the Great Lakes region to achieve its vision of skies filled with waterfowl today, tomorrow, and forever.