Emergent plants grow in standing water, and sedges, grasses, and water-tolerant forbs grow in the seasonally inundated soils around the margin of the wetland. Emergent plants reproduce by seed during natural drawdown cycles caused by drought. Marshes are classified as shallow or deep, based on the water depth and the persistence of water through the season. Deep marshes have water up to three feet deep. Shallow marshes have 6 inches or less of standing water.
Marshes are among the most productive wetlands for birds and mammals.
Ducks, geese, wading birds such as herons and egrets, rails, terns, and songbirds make their home in marshes. Raptors, including ospreys, bald eagles, northern harriers, and short-eared owls, hunt and nest in or adjacent to marshes. Muskrats, mink, voles, and mice are common. Marshes serve as nurseries for young fish. They also stabilize soil and improve water quality by filtering sediments and absorbing nutrients.