By Doreen Pfost
Doreen Pfost is a former communication specialist for the Rainwater Basin Joint Venture and author of “This River Beneath the Sky: A Year on the Platte” (2016).
With a new growing season upon us, the annual waterfowl and crane migration seems like the distant past, especially to birdwatchers who visited their favorite Rainwater Basin wetlands in March and found neither water nor waterfowl. Wildlife areas where people searched in vain for birds are now filled with a different type of activity – which looks a lot like agriculture.
To visiting birdwatchers in March, the landscape south of the Platte River may have seemed like little more than a vast expanse of brown corn stubble. But here and there in the gently rolling land are low spots that – when there is rain or snowmelt – collect water. Sometimes these wetland areas cover just an acre or so, sometimes for just a few weeks. But those weeks fortuitously coincide with the annual movements of water-dependent birds. Though now only a fraction of what once existed, wetlands in Nebraska’s Rainwater Basin have, for millennia, attracted millions of migrating ducks and geese each spring, along with sandhill cranes, shorebirds, pelicans, and the occasional whooping crane.
In some years, when the melting snow is copious, water seems to fill every low spot on the land, and all that water seems to be filled with birds – birds so numerous that when they take off, they may briefly blot out the sky. In other years, like this one, many wetlands were not wet at all, and the birds stopped elsewhere – farther east, farther north – leaving some birdwatchers to wonder, perhaps, if something was wrong.
But dry spells in this region are the natural order of things; and the humans who watch over the Rainwater Basin wetlands have learned to use the dry years as opportunities to make habitat improvements so that when the rain and snow eventually return, the birds will, too. Through a partnership called the Rainwater Basin Joint Venture, a variety of government agencies, non-profit organizations and individual landowners have forged a tradition of cooperation that’s good for both agriculture and wildlife.
So, what makes a wetland suitable for migrating ducks and geese? First, obviously, the wetland must hold water, providing a secure place for birds to rest. Secondly, it must grow a bounty of wetland plants whose seeds provide essential nutrients to supplement the birds’ principle calorie source: corn.
These days, maintaining a “natural” wetland plant community for waterfowl actually requires some non-natural human intervention. Like most plant communities, wetlands, if left to their own devices, progress through a “succession” of growth, from herbaceous (and seed-rich) annual plants to perennials, to shrubs and trees – unless that succession is interrupted by an external force. The external forces that once interrupted plant succession in what’s now south-central Nebraska included prairie fires, flood-drought cycles, and roving herds of grazing bison. Today, humans called “land managers,” many of whom work for government agencies, seek to accomplish what nature no longer does.
The majority of the Rainwater Basin region’s wetland habitat is on public land: state Wildlife Management Areas, or WMAs, managed by the Nebraska Game and Parks Commission, and federal Waterfowl Production Areas managed by the U.S. Fish and Wildlife Service’s Rainwater Basin Wetland Management District. Virtually all of these wetland areas are former farm land, which landowners, tired of trying to coax a profit from flood-prone acres, willingly sold to the government.
To be useful as waterfowl habitat, however, wetlands on the newly purchased land usually needed to be restored. Restoration of a wetland means restoring its “hydrology”: the natural cycle by which it collects and holds water, and then eventually dries out. Restoring hydrology is not a delicate operation. To bring back the water and ducks, you first have to bring in the heavy earth-moving equipment. Past efforts to make the wetland farmable must all be reversed. That means removing any soil that was used in an attempt to fill the wetland; it means filling any ditches that were dug in hopes of draining the wetland; and it means removing dikes that trapped or re-routed the water away from the low spot in the land. Other restorations involve removing accumulated sediment – which can wash into a wetland from surrounding crop fields – along with rank weeds like reed canary grass and cattails.
Also affecting wetlands’ hydrology are the region’s hundreds of irrigation pits – excavations that resemble steep-sided ponds. Designed to capture irrigation water so that it could be used repeatedly on crop fields, they also capture rainfall and snowmelt that would otherwise flow downhill to the nearest wetland.
Laurel Badura, a wildlife biologist with the U.S. Fish and Wildlife Service’s Partners for Fish and Wildlife program, has worked with local landowners to fill nearly 200 of these pits in recent years. Her goal is to get as many landowners as she can to fill the pits in a given wetland’s watershed, thus restoring the wetland’s hydrology as much as possible. Sometimes, it doesn’t take much persuading. After the first few phone calls, she says, word gets out to the neighbors. “It spreads like wildfire, because those pits are in the way.”
Many of the pits became obsolete – and even a nuisance – when landowners switched from gravity-type irrigation systems to center-pivot irrigation systems whose large sprinklers circle the field – unless their path is interrupted by a hole in the ground. By filling the pit, a landowner can remove an obstacle in the field and also gain a few more acres of crop land, but it’s expensive. That’s where Badura can help, by pooling resources of Rainwater Basin Joint Venture partners to cover expenses of filling the pit, and helping to locate a soil source, if needed. It’s a win for the farmers and also for the wildlife that will use the improved wetland.
Once the water regime is restored to a wetland, the next ingredients in the recipe are wetland plants – which often require surprisingly little effort. Nebraska Game and Parks Commission’s wetland/wildlife biologist Randy Stutheit, who has overseen many such restorations, explains that with the removal of sediment or fill, “You uncover the historic seed bank that’s been buried.” Once exposed, the long-dormant seeds germinate and the wetland plant community returns…and can be maintained, with some human assistance.
“After you get the wetland back into good shape,” Stutheit said, “you’ve got more reliable water conditions that you can plan on, and it makes management much simpler.” Management involves a variety of measures, including herbicide in the case of noxious weed infestations. Routine management often involves mimicking those natural forces that once interrupted plan succession: prescribed fire, altering water levels as if in a flood-drought cycle, and – in place of bison – cattle to graze on the wetland and upland plants.
Some visitors to Rainwater Basin wetlands wonder at the presence of boundary fences around the properties, and at the cattle roaming in an area that’s intended for wildlife. Brad Krohn, project leader for the Rainwater Basin Wetland Management District, explains that grazing on the region’s public lands was a decades-old practice – at least on those parcels that had perimeter fencing. And since the early 1990s, land managers have refined the use of grazing as a tool to manage vegetation. Today, public wetlands are all fenced, and dozens of livestock producers, or “cooperators,” graze their cattle on state and federal wetlands and cooperate in the effort to manage plant communities. Cooperators adhere to individually tailored grazing plans that outline numbers of cattle, duration of grazing, and other parameters, all with the goal of achieving a plant community that will benefit waterfowl the following spring.
Other management tools, like herbicide treatments and prescribed fire, have their place but are costly and labor intensive. Grazing, on the other hand, can be both effective and economically sustainable. It’s good for the cooperators, because it offers a forage source close to home and at a reasonable cost. The high quality of the forage means that it’s good for cattle, too, Krohn said. The arrangement is also good for the Wetland Management District. “It really ties us in with the community,” Krohn said. And fees paid by the cooperators go back, for the most part, into wetland maintenance. Above all, the program is good for the migrating birds that will feed and rest in the wetlands next year – or maybe the year after.
One of the few things that’s certain about spring migration in the Rainwater Basin is that it changes every year. Another certainty is that excellent habitat in the region can only be accomplished when agriculture producers and conservation professional work together. The next time precipitation fills those wetlands with water – and birds – we’ll have them to thank.