Freshwater Marshes

Deepwater marsh vegetation with hardstem bulrush and stiff arrowhead.

Deepwater Marsh vegetation with hardstem bulrush and Stiff Arrowhead.

Freshwater marshes differ from wet and sedge meadows in that most of the year the water table is above ground; in other words there is usually standing water.  Shallow marshes are susceptible to drying out in late summer, and both are often dried out during severe drought.  Drought is an important part of the life cycle of these plants, especially emergents like the bulrushes whose seeds will not successfully germinate underwater.

Like many other wetlands, marshes were once thought of as being wasted land because you could not build or farm on the soil.  However, our ancestors took advantage of the wetlands natural diversity.  Ducks and other waterfowl were harvested for food and down.  Wild Rice was a staple of many Native American tribes and Common Reed was used as a building material by people throughout the world.  Today we have realized the many ecological services that marshes provide like flood control, maintaining water quality, and carbon sequestration.

Shallow Marsh

In the dry months of summer a shallow marsh has dried up at the Grand River Marsh State wildlife Area.  This little marsh is ringed with Common Arrowhead, Common Bur reed, which in turn is surrounded by a sea of Reed Canarygrass.

Shallow Marshes

Shallow Marshes have water depth less than six inches.  Shallow marshes have many of the plant and animal species found in sedge meadows, and deep marshes.  Shallow marshes may be void of fish during the drier summer months, but when flooded in spring they can be crucial spawning areas for fish like Northern Pike.

Deepwater Marshes

Deepwater Marshes typically have between six inches to three feet of water.  Many truly aquatic plant species like Coontail (Ceratophyllum demersum), Common Waterweed (Elodea canadensis) and White Water-Lily (Nymphaea odorata) are found here.  Deepwater Marshes’ ecosystems may have fish in them year-round and can be very important for spawning and rearing of young fish.  These wetlands dry out less frequently than shallow marshes, but may become dry during prolonged severe drought.

Time lapse video of a Deepwater Marsh.  Willows, Stiff Arrowhead and a number of other aquatic plants blow in the breeze.

Lake Littoral Zone

Shallow Open Water Wetlands occur in areas from 3 to 6 feet in depth, and the littoral zone of a lake is defined as the area of the lake in which enough light can penetrate to the bottom to support rooted plants.  This depth can be less than a few feet in highly turbid waters, to dozens of feet in very clear water.  This zone is where much of the productivity of lakes occurs.  The types of plants that occur here are often the same that appear in deep, or even the shallow marsh environment.  These habitats can be similar to Deepwater Marshes; both rarely dry out completely, but some of the lake or marsh bed may become exposed during droughts, which counterintuitively has a rejuvenating effect on many aquatic and wetland plants.

Marsh Animals

Abundant and highly productive aquatic and wetland plant leads to abundant animal life of all kinds.  Hundreds of species of insects and invertebrates spend part or all of their life cycle hiding and feeding in the thick vegetation.  Dragonfly larvae prey on other insects, young fish and amphibians.  The standing water attracts American Toads that lay their eggs and then disperse into the uplands, while Leopard Frogs often spend their whole lifecycle in marsh habitat.  The Northern Watersnake is a reptile that patrols the thick vegetation looking for a meal of frogs or fish.

Birds are abundant in the marsh too.  Canada Geese nest on muskrat lodges and lead their goslings into the water to feed on aquatic plants and the invertebrates they harbor.  Black Terns nest in clumps of floating vegetation either alone, or in small colonies.  These sooty looking terns search the water of the marsh for tiny fish and a few invertebrates to feed their hungry young.  One of the most conspicuous of the birds, spring through fall, are Red-wing Blackbirds who loudly proclaim their territories in spring and gather in huge numbers in the fall.  Smaller birds like the Marsh Wren also make their presence known by their melodious singing.

One mammal that lives in the marsh can be responsible for its creation.  American Beavers build dams of sticks, mud and rocks, blocking creeks and small rivers, creating ponds and marshes.  While the Muskrat does not create dams and ponds, they are responsible for altering and creating a diverse marsh ecosystem.  Muskrats dig up plants, roots and all to feed on and build their lodges.  This creates areas of open water in the marsh that might otherwise be a firm mat of roots and living plants.

Marsh Plants

Marsh wetlands are great places to see some amazing plants, but it can take a little work.  If you’re lucky, somewhere nearby will be a nature preserve with a boardwalk that will let you get access without getting wet. The next best option to rubber boots and chest waders is a canoe or skiff to get you into the deeper areas of the marsh.  Once in the marsh you’ll be greeted by some of our most beautiful and interesting wildflowers like White Water Lily, Blue Flag Iris, Marsh Milkweed, Cardinal Flower and many others.  Even the plants without showy flowers can be visually striking.  The mace-like seed heads of Common Burreed are hard to miss, and the grace of Soft Stem Bulrushes are also an attractive element of marshes.

Shallow marsh vegetation

Shallow marsh vegetation

Marsh Amphibians and Reptiles

 Marsh Birds

  • Green Heron (Butorides virescens)
  • Canada Goose (Branta canadensis)
  • Forster’s Tern (Sterna forsteri)
  • Black Tern (Chlidonias niger)
  • American White Pelican (Pelecanus erythrorhynchos)

Marsh Mammals

  • American Beaver (Castor canadensis)
  • Muskrat (Ondatra zibethicus)
  • Raccoon (Procyon lotor)
  • Moose (Alces alces)

Marsh Fish

Marsh Plants

Marsh Plant Survey

Marsh Plant Survey

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