Habitat management activities on Waterfowl Production Areas focus on the restoration and maintenance of grasslands and associated wetlands for the benefit of waterfowl and other migratory birds. Tools available to the wetland manager include prescribed fire, water level manipulation, waterfowl nesting structures, mowing, tree and brush removal, haying and grazing, where appropriate.
District staff work with private landowners and form effective partnerships to restore and/or enhance drained wetlands and some grasslands within the five-county working area. With landowner approval, bulldozers and backhoes are used to plug drainage ditches, break drain tiles, and install water control structures to maintain desired water levels of the wetlands. In time, wetlands, once drained and forgotten, can be revived to carry on their vital role as part of the prairie landscape.
Much of the land in the prairie pothole region has historically been farmed. When the District acquires a new tract of land, it restores the wetlands on the new property, and seeds the uplands with native origin grasses and forbs (wildflowers). The District harvests some of the needed seed from local native prairies, and also purchases some local origin grass and forb seeds to diversify the seed mix.
A diverse seed mixture is important because the wildflowers provide food for many species of insects. Grassland birds feed on the insects found in these prairies. A grassland tract with diverse species composition can support more wildlife that is dependent on that food source. Plant species diversity also provides variability in the grassland structure. Some wildlife species need dense grasses overhead and passageways near the ground; others like shorter, open areas in a grassland. Plant diversity provides better cover, nesting habitat and food for a larger variety of wildlife species.
When the Fergus Falls District acquires a new tract of land, one of the first things done on the new unit is wetland restoration. A wetland expert analyzes the property and determines where wetlands have been drained or filled. Then heavy equipment is used to plug ditches, break tile lines, and scrape out soils to restore wetlands to their natural depth. Once the dirt work has been completed, the wetlands are allowed to fill with water naturally through rain water run-off and snow melt in the spring. If determined feasible and appropriate, water level control structures are sometimes installed so that water levels can be managed to maximize the habitat value.
Invasive fish have become a problem in many wetlands in Minnesota. These fish disrupt natural processes in wetlands sometimes causing poor water quality and reducing the value of those wetlands for wildlife. Invasive fish can be eradicated from marshes if a wetland is drawn down before winter. The fish will freeze out or die from oxygen depletion over the winter. When we use draw downs to remove fish, a barrier is necessary to keep fish from re-entering the system. We use sloped, smooth pipes called velocity tubes, pipe elbows, rotating screens, or swinging fingers to prevent fish from moving upstream into managed wetlands. Invasive fish can also be removed by stocking predator fish or chemical treatment with rotenone, which is a chemical derived from the roots of a South American plant. Rotenone kills fish by disrupting the way they absorb oxygen into their cells. All three methods of removing invasive fish can improve wetland quality and wildlife habitat.