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Wetlands

Wetlands provide some of the most important ecological functions of any habitat type. They provide nursery areas for fish, support an abundance of wildlife, help control flooding, and filter nutrients and sediments and even some harmful pollutants. In the process, wetlands improve water quality and enhance our natural environment. By learning about wetlands and creating a wetland model, students observe these concepts in action and watch what can happen when a wetland disappears.

Grade Level: 4-8 grades

Performance Expectations:

  • MS-LS2-5 Ecosystems: Interactions, Energy and Dynamics. Evaluate competing design solutions for maintaining biodiversity and ecosystem services.
  • MS-ESS3-3 Earth and Human Activity. Apply scientific principles to design a method for monitoring and minimizing human impact on the environment.
  • MS-ESS3-4 Earth and Human Activity. Construct an argument supported by evidence for how increases in human population and per-capita consumption of natural resources impact Earth’s systems.

For alignment, see: Wetlands NGSS Summary

Objectives

  • Observe building a model wetland.
  • Understand that wetlands are defined by plants, soil and water.
  • Identify some wetland types and their locations.
  • Relate the importance of wetland function to people’s needs and daily lives.
  • Demonstrate wetland functions using the model and draw conclusions from observations of multiple trials of the model, including modifications.

Background

Wetlands are an important feature of the Great Lake region. Marshes, a type of wetland, are found along the Great Lakes, but in some areas they’ve decreased by 90 percent. It is estimated that Michigan once had over 11 million acres of wetlands. Today, a little over 5 million acres remain.

A wetland is an area that periodically has waterlogged soils or is covered by shallow surface water. This surface water supports plants and animals that are adapted to living in a watery environment. Some major functions of a wetland are:

  • Reduce flooding (flood buffering)
  • Filter pollution
  • Prevent soil erosion
  • Provide habitat for aquatic and terrestrial animals and plants
  • Serve as breeding, feeding and nesting grounds
  • Wetlands are classified as marshes, bogs, swamps, vernal ponds and wet meadows. These are the types found in Michigan. Some non-Michigan wetlands are salt marshes, mangrove swamps and prairie potholes.

Several Types of Great Lakes Coastal Wetlands:

  • Embayments
    These bodies of Great Lakes water are partly protected from the full force of the lakes. They may be open embayments, which are protected by the curvature of the Great Lakes shoreline. Or they may be protected embayments, which are carved into the shoreline and protected by features such as sand spits.
  • River Delta
    The mouth of the St. Clair River is a good example of a river delta. River deltas form when sediments flow downstream and build up near a river’s mouth. This process produces slower currents that allow sediment to accumulate, forming islands and bars. The channeled water produces a branched system of waterways, vegetation, mud flats and pools.
  • Dune and Swale
    These unique habitats feature an alternating pattern of narrow sandy ridges and saturated depressions (or swales) parallel to a lakeshore. This topography formed when glaciers retreated and left behind mounds of sand and sediment in a series of dunes or ridges. A good example of a dune and swale habitat is located near Sturgeon Bay in northwest Michigan. These areas provide excellent habitat for many migratory bird species.
  • Drowned River Mouth
    These flooded areas are characterized by a permanent channel that meanders through a flood plain. This habitat is partly separated from the Great Lakes by sandy or rocky spits. Marshes often form in the calmer areas behind the spits and provide important spawning and nursery areas for fish and migrating waterfowl.
  • Emergent Marsh
    One habitat closely related to coastal wetlands is called an emergent marsh, which is linked to fluctuating Great Lakes water levels. When water levels fall, for instance, open mudflats are exposed and eventually sprout with vegetation, creating an emergent marsh. These areas are among the most productive of all habitats for waterfowl and other waterbirds. Large marshes or marshes within a wetland complex often support a diverse breeding bird community because of the variety of habitat conditions. The Red-necked Grebe, Least Bittern, Redhead, Ruddy duck, and Marsh wren are among the bird species that nest exclusively in emergent marshes.

To learn more about marshes and restoration, see Lesson: Restoring Marshes

Activity

  • Wetland in a Pan
    Summary: Students observe a simple wetland model that demonstrates wetland functions including filtering, flood buffering and acting as a nursery for aquatic organisms.
    Time: Two 45-minute class periods (90 minutes)