Three common wetland management activities are conducted in Illinois to improve or enhance habitat for wildlife: manipulating water levels for moist-soil plant growth or mudflat exposure, timed flooding of forested wetlands (also called “green-tree management”), and prescribed burning of wetland vegetation. Unlike other habitats, wetlands can provide high-quality habitat if they are simply protected and maintained, without any active management. All wetlands should be protected from any disturbance except' the three specified here and need to meet the minimum standards outlined in "Management Considerations" for plant-species diversity, successional stage, and structural components. All of these considerations together comprise a practice. If you remember the collective importance of all the criteria in a practice when managing your wetland, you can know you're providing suitable habitat for wildlife.

At a minimum, any existing or newly created pond, lake, marsh, swamp, wet meadow, or other wetland should be protected from detrimental disturbances such as pollution and dredging. If littering has previously occurred, remove the trash, such as empty containers and old tires, to improve the water quality.

Protection of the watershed is key to protecting any aquatic habitat from sedimentation. Avoid forest clearcutting, which significantly increases the runoff and the sediment load to the body of water. Clearcutting along the banks can raise the temperature of stream water, often causing a negative change in the ecosystem. Minimize or eliminate any unnecessary tillage in the watershed. If tilling must be done, use soil conservation techniques such as contour farming and "minimum tillage." Installing filter strips and riparian buffers can also greatly reduce the sediment load and pollution that would otherwise enter the wetland. Filter strips can be any type of grass that will stabilize the soil around the wetland and provide nesting cover. Fescue and reed canary grass are not recommended because they provide little additional value to wildlife and aggressively outcompete other wetland plants. Wetlands and ponds located in the middle of crop fields can greatly benefit from the establishment of filter strips without the sacrifice of much cropland. Filter strips in any location should be at least 50 feet wide; wider is even better. Consult the chapter on grasslands for speciesand planting specifics on grass filter strips.

Riparian buffers of trees and shrubs can also trap sediments and pollution and can stabilize banks that are eroding. Plant woody species that are suited to bottomland and moist habitats. The buffer strip should be at least 50 feet. wide; wider is better. Consult the chapter on woodlands and woody cover for specifics on species and planting.

Wetland Protection with Moist-Soil Management

In some wetlands, artificially manipulating water levels can create a mosaic of wetland types that attract a variety of wildlife. Water levels and vegetation can be managed to produce herbaceous plants, mudflats, and open water.

To create conditions favorable for moist-soil plants to grow, in the fall gradually flood the wetland with two to ten inches of water, and let remain over winter. Gradually dewater from ice-out until midsummer; this allows spring migrating birds to feed on invertebrates. The plant seeds will germinate during summer, once water is drained. Vary the flooding and dewatering times from year to year to encourage vigor and density of desired plants.

Biologists have found that food production for several wildlife species, including waterfowl, can be enhanced by duplicating the natural cycles of wet and dry periods that occur when lake or stream water levels fluctuate. Typically a marsh's water level is lowered during the late spring or early summer, allowing moist-soil plants to grow in the exposed mudflats. Tubers and seeds provided by the new plants are used by species like the mallard. Such water management encourages plants such as cattail, bulrush, ferns, common reed, and erect sedge. The drawdown also provides areas for birds to feed on invertebrates. In the fall, water levels are allowed to rise again several feet, inundating the mudflats and creating additional areas for migrating waterfowl to rest and feed. The timing, duration, and frequency of drawdowns are all important. Drawing down earlier may encourage certain plant species, while a later drawdown will help completely different ones. For specific information on the benefits of mudflats to wildlife and how to develop and maintain them, see the U.S. Fish and Wildlife Service Waterfowl Management Handbook in the suggested reading list.

Wetland Protection with Green- Tree Management

Green-tree management aims to mimic the natural flooding that occurs in some bottomland forests during dormancy. A great variety of wildlife benefit, including migrating waterfowl, birds of prey, bottomland songbirds, and reptiles and amphibians.

Flooding should begin gradually in late fall, when trees are fully dormant. Water levels should be maintained at a fairly stable depth of twelve to eighteen inches during winter. Before trees leaf out in the spring, a gradual drawdown should occur, over a period of at least two to three weeks. Try to match the drawdown period with the arrival of migrating waterfowl. Remember, you are trying to mimic what occurs naturally in some bottomland forests.

Stable water levels are desirable in midwinter because suspended nutrients usually peak about three months after flooding. Avoid rapid drawdowns. Gradual drawdowns prevent a high loss of nutrients, result in more stable wildlife habitat, increase invertebrate availability, and promote the long-term health of the system.

Do not flood the woodland every year, and rotate areas so they are flooded only every other year or less. Flooding can alter bottomland plant communities. Pin oaks and swamp white oaks tolerate extended flooding. Other bottomland trees and some wildflowers that inhabit bottomlands, such as bluebells, do not. Table 5.3 lists ten tree species that tolerate extended flooding. If you have questions about this practice, contact the IDNR.

Wetland Protection with Prescribed Burning

Introducing occasional fire during the late fall or early spring to a wetland that is artificially or naturally dry can greatly improve the structure and diversity of the vegetative community, thus improving the wetland for wildlife. Conduct a prescribed burn on emergent, herbaceous aquatic vegetation (cattails, sedges, grasses). Burn no more than a third to half of the vegetation in anyone year, and avoid the spring and fall waterfowl migrations and the summer nesting season. See Conducting Prescribed Burns in the suggested reading list for information on planning and conducting a safe prescribed burn.