Multi-Species Benefits of Wetlands Conservation

By Jennifer Boudart

When it comes to productivity, wetlands are right up there with tropical rain forests and coral reefs. That’s due to the unique characteristics that are typical of these ecosystems, says Dr. Ellen Herbert, DU’s senior scientist. “Wetlands are not quite water and they’re not quite land—they’re kind of in the middle. As a result, they support abundant plant growth and provide food and shelter for a remarkable number of species,” she notes.

Statistics certainly bear this out. All of North America’s waterfowl depend on wetlands, of course, but half of the continent’s other migratory birds use them at some point during their annual life cycles. In total, these ecosystems are home to some 900 species, representing every class of animal, from tiny invertebrates to the largest mammals. This biodiversity includes many game species in addition to waterfowl, such as wild turkeys, prairie grouse, mourning doves, ring-necked pheasants, woodcock, black bear, moose, and white-tailed deer. Wetlands also harbor various freshwater and saltwater fish, including salmon, northern pike, bass, and trout. In fact, an estimated 90 percent of the fish caught by recreational anglers in the United States depend on wetlands for reproduction and survival.

Given this rich biodiversity, it’s not surprising that the habitats conserved by Ducks Unlimited are enjoyed by a variety of outdoor enthusiasts, from hunters and anglers to hikers and bird-watchers. It’s also not surprising that DU’s mission overlaps with many other nonprofit conservation organizations supported by these constituencies. “Working with other groups that are concerned with species that live in wetlands or benefit from wetlands is a natural fit for us,” Herbert says.

In California’s Central Valley, for example, DU and its partners are researching how winter-flooded rice fields, which are managed by private landowners for waterfowl, can also benefit Chinook salmon. In areas where natural floodplain wetlands have been lost, research shows that juvenile salmon raised in flooded rice fields grow larger on average than those raised in neighboring streams and rivers.

Other DU projects in the Central Valley also benefit species like the giant garter snake. This highly aquatic, threatened reptile is endemic to the region and relies on the same wetlands that support wintering waterfowl. DU consistently considers the habitat needs of the giant garter snake when planning conservation projects within the species’ range, such as wetland-infrastructure improvements on Gray Lodge Wildlife Area. At the outset of this project, DU formed a working group with various experts to minimize disturbance of the snakes when delivering this work.

On the Great Plains, DU is partnering with the US Fish and Wildlife Service (USFWS) to develop projects that not only benefit waterfowl but also restore and protect habitat for federally endangered or threatened species. In North Dakota, DU is implementing the first federally approved Dakota Skipper Conservation Bank, which will mitigate impacts of planned natural resources development on habitats that support this threatened prairie butterfly. DU will restore and protect roughly 300 acres of native prairie on private land that is currently inhabited by Dakota skippers. Revenue from future sales of conservation bank credits will go to DU, while the restored prairie will benefit the landowner’s cattle operation and improve nesting habitat for ducks.

In the Mississippi Alluvial Valley, changes in flooding cycles, coupled with the decreasing effectiveness of aging water-control infrastructure, have negatively impacted bottomland hardwood forests. These seasonally flooded woodlands provide wintering habitat for roughly 40 percent of the ducks found in the Mississippi Flyway. They also provide migration and breeding habitat for a variety of bat species. These unique mammals are closely associated with bottomland hardwood forests and use tree cavities for roosts and raising young. DU projects in Arkansas and Mississippi are helping the bats by protecting stands of bottomland hardwood trees and restoring emergent moist-soil wetlands that provide food resources for waterfowl, bats, and many other wildlife species.

Along the East Coast, DU is working with the USFWS and other partners to restore and protect salt marshes, which provide vital migration and wintering habitat for American black ducks and other waterfowl species. These fragile wetlands also support many species of concern, such as the saltmarsh sparrow and the threatened eastern black rail. In Maine, DU staff and volunteers use hand tools to dig shallow interconnected waterways—called runnels—throughout degraded salt marshes. This work restores the natural ebb and flow of the tides, increasing sedimentation, enhancing the growth of emergent vegetation, and raising the elevation of the marsh. By increasing marsh elevation, these efforts provide more secure migration and wintering habitat for waterfowl and breeding habitat for saltmarsh sparrows and other birds. 

In South Carolina, DU works with government agencies and private landowners to manage wetland impoundments to increase food resources for wintering waterfowl and provide optimal breeding habitat for eastern black rails in summer. These efforts also benefit a host of migratory birds and local wildlife as well as fisheries. 

According to Herbert, DU is investing in several areas of research to generate more specific data about the multi-species benefits of its conservation work, which can in turn be used to inform project planning. One example is DU’s work with the US Geological Survey and the Cornell Lab of Ornithology to develop tools that will gather data about habitat use by different bird species. This information will then be used to predict which species in addition to waterfowl will benefit from habitats restored by DU.

In a similar vein, DU is collaborating with several nonprofit and university partners to deploy autonomous audio recording units at DU restoration sites along the Missouri River. “This technology is being used to record and identify the calls of various species of bats, insects, birds, and amphibians,” Herbert explains. “In this way, we’ll be able to fingerprint what kinds of species come back to each restored site. We can use that information to better communicate the multi-species benefits—which our projects have always offered—to others and expand our partnerships and habitat work on vital landscapes for waterfowl and other wildlife.”