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Wetland Modifications

Wetlands are an interface between terrestrial and aquatic systems and have been identified as one of the most diverse and productive systems on earth, with average annual production comparable to that of tropical forests. They are distinguished by their unique soils, water-tolerant plants, and hydrologic regimes. These components differ dramatically between various types of wetlands; consequently, wetlands support many different assemblages of plants, fish, insects, birds and other wildlife. Additionally, wetlands provide a wide range of direct benefits to Michigan's citizens and visitors, including recreational opportunities, flood and storm water storage, groundwater protection and recharge, erosion control, and water quality protection by filtering sediment and removing nutrients (Cwikiel 2003). These functions are extremely difficult to restore or artificially replicate, which makes it critical to expend considerable efforts to minimize losses of wetland systems. Estimates of the monetary value of wetlands, including services such as water regulation, nutrient cycling, and recreation, are as high as $598.30 per acre per year (Costanza et al. 1997). See the Ecological Overview for more information about the extent of wetlands that have been lost in Michigan and sources of wetland modification.

Wetlands are vital for a variety of Michigan species: they provide important breeding, spawning and nursery habitat for many fish species; nearly all of Michigan's amphibians are dependent on wetlands, particularly for breeding; they provide resting sites for migrating waterfowl and nesting or foraging sites for a variety of landbirds, waterbirds and waterfowl; and they are preferred by mammals such as muskrats, otter and beaver. Although wetlands make up only 3.5% of the United States' land area, more than one-third of threatened and endangered species are dependent on wetlands to meet their habitat needs (Mitsch and Gosselink 1993). Federally threatened or endangered animals that are wetland obligates in Michigan include Mitchell's satyr butterfly, Hine's emerald dragonfly and copperbelly water snake. Several federally threatened or endangered plants in Michigan are also wetland dependent, including the eastern prairie fringed orchid, Michigan monkey flower, Hall's bulrush and Houghton's goldenrod.

Effects of wetland loss extend well beyond the conspicuous loss of acreage. As wetlands are lost from a watershed, storage capacity is lost and downstream streamflows experience more severe flooding during spring and drought during late summer and early fall. More intense flooding increases soil erosion and sediment loads (see Pollution: Altered sediment loads).

Excess nutrients that accumulate when a wetland's ability to filter nutrients and contaminants is compromised can cause undesirable increases in algae and aquatic plant growth. In turn, increased respiration by plants reduces dissolved oxygen levels, potentially killing aquatic organisms. In an attempt to mimic these important functions, many communities have constructed artificial wetlands and have incorporated them into their waste treatment systems.

Michigan's 3,200 miles of Great Lakes shoreline have experienced fluctuating water levels since first measurements were taken in the 1860s (Hoagman 1998). Due to recent decreases in water levels, Michigan has experienced an increase in the amount of coastal wetlands as new wetland vegetation has grown where the lake bottom has been exposed. Recent legislation has allowed certain beach maintenance and grooming activities (such as leveling of sand, grooming, mowing, path construction) to occur without an MDEQ permit, if done between the ordinary high water mark and the current water edge (MDEQ 2003a). However, removal of this vegetation may further threaten coastal wetlands and must be monitored.

Conservation Needs to Address Wetland Modification Threats:

Land & Water Protection

  • Increase regulatory protection for small, isolated wetlands

Land, Water & Species Management

  • Explore development alternatives that avoid affecting wetlands, including selection of alternative project sites

  • Consider all feasible and prudent efforts to avoid wetland alteration before using wetland mitigation

  • Ensure that mitigation occurs on-site or contiguous to the remaining wetland

  • Develop recommended strategies and designs that have the best potential to create functioning wetlands in mitigation projects

  • Develop wetland loss mitigation strategies that ensure retention of the existing variety of wetland types

  • Implement best management practices that protect wetlands

  • Implement wetland restoration on private lands

  • Maintain or enhance processes that support wetlands in a landscape, including establishing buffer zones

  • Preserve cross drainage at road and trail crossings in wetlands

  • Maintain the existing diversity of wetland resource types across a landscape

Law & Policy

  • Strengthen current regulations and enforcement to encourage no net loss of wetland resources and reduce the rate of loss of natural wetlands

  • Provide tax or other incentives for retention, restoration and development of wetlands on private lands

Education & Awareness

  • Provide private landowners with information regarding available Federal funding sources for restoration of wetlands, including the Wetland Restoration Program, Landowner Incentive Program and Wildlife Habitat Incentive Program

  • Encourage use of best management practices to protect wetlands

Research, Surveys & Monitoring

  • Develop a common classification system to describe wetlands and ensure that all representative wetland types present across a landscape are identified and maintained

  • Complete a statewide wetland inventory

  • Conduct research to better understand the functions of wetland features, especially bogs and fens

  • Conduct basic research on remediation and water recharge

  • Develop and test best management practices to protect wetlands

  • Conduct research to develop guidelines for wetland buffer zones and connectivity needs

  • Identify wetlands not currently regulated and determine their importance to maintaining wildlife diversity

  • Conduct research to develop and test strategies and designs for functional wetlands in mitigation projects

  • Monitor wetland creations and restorations to ensure they provide the anticipated wetland benefits

  • Conduct research to determine whether there are differences in wildlife value between: natural and human-made wetlands; intensively managed and passively managed wetlands; and beaver-created wetlands and other wetlands