|In geography, a
marsh is a type of wetland, featuring grasses, rushes, reeds, typhas, sedges, cat tails, and other herbaceous plants (possibly with low-growing woody plants) in a context of shallow water. A marsh is different from a swamp, which is dominated by trees rather than grasses and low herbs. The water of a marsh can be fresh, brackish or saline. Coastal marshes may be associated with estuaries and along waterways between coastal barrier islands and the inner coast. Estuarine marshes often are based on soils consisting of sandy bottoms or bay muds.|
The shallow-water marsh provides feeding grounds for "wading" birds such as cranes and egrets. The marshland is "ephemeral", meaning that the water supply is dependant upon seasonal periods of precipitation and run-off. In our desert climate, there are times during the year that the marsh area may be completely dry.
Diverse species of mammals, plants, insects, amphibians, reptiles, birds and fish rely on wetlands for food, habitat or shelter. Wetlands are some of the most biologically productive natural ecosystems in the world, comparable to tropical rain forests or coral reefs in the number and variety of species they support. Although wetlands make up only about 5 percent of the land area of the lower 48 states, more than one third of threatened and endangered species live only in wetlands.
An additional 20% of the country's threatened and endangered species use or inhabit wetlands at some time in their life. Some species must have a wetland in order to reproduce. Migrating waterfowl rely on wetlands for resting, eating and breeding areas, leading to increased populations. As noted, the appeal of wetlands and the diversity of plant and animal life they attract contribute to or support many businesses.
Deep marsh plant communities have standing water depths of between 6 inches and 3 or more feet during the growing season (Shaw and Fredine 1971). Herbaceous emergent, floating, floating-leaved, and submergent vegetation compose this community, with the major dominance by cattails, hardstem bulrush, pickerelweed, giant bur-reed, Phragmites, wild rice, pondweeds and/or water-lilies.
SOILS: Lacustrine deposits.
HYDROLOGY: Permanently to semi-permanently inundated.
Shallow marsh plant communities have soils that are saturated to inundated by standing water up to 6 inches in depth, throughout most of the growing season (Shaw and Fredine 1971). Herbaceous emergent vegetation such as cattails, bulrushes, arrowheads, and lake sedges characterize this community.
VEGETATION: The above shallow marsh is dominated by broad-leaved cattail (Typha latifolia) narrow-leaved cattail (Typha angustifolia), giant bur-reed (Sparganium eurycarpum), giant reed grass (Phragmites australis) and river bulrush (Scirpus fluviatilis). Other species include softstem bulrush (Scirpus validus), lake sedge (Carex lacustris), broad-leaved arrowhead (Sagittaria latifolia), lesser duckweed (Lemna minor), star duckweed (Lemna trisulca), water smartweed (Polygonum amphibium), bulblet water hemlock (Cicuta bulbifera), rice cut-grass (Leersia oryzoides), great water dock (Rumex orbiculatus) and indigo bush (Amorpha fruticosa). During the past ten years, a purple loosestrife (Lythrum salicaria) infestation has slowly expanded in spite of control efforts (removal by hand). It threatens to overtake this highly diverse shallow marsh community and establish a purple loosestrife monotype.
SOILS: Seelyeville muck (Typic Borosaprists), a very poorly-drained soil with an upper organic layer greater than 51 inches in depth (and can be many feet in depth). Landscape position is a backwater lake and marsh complex within the broad valley of the Minnesota River.
HYDROLOGY: This backwater area is primarily groundwater fed, but is also inundated during flood events of the Minnesota River. This particular shallow marsh typically has saturated to inundated soils.
(Source: U.S. Fish and Wildlife Service and NRCS)