The Wetlands of Missouri

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Published on: Sep. 2, 2001

Last revision: Nov. 9, 2010

the river, a number of oak species (e.g., pin oak), shellbark hickory and pecan dominate the forest. The understory of these areas contains shrubs such as pawpaw, spicebush and deciduous holly. Sedges often cover the ground.

Animal inhabitants of these forests include rare cerulean warblers, barred owls, prothonotary warblers, small-mouthed salamanders, mole salamanders and wood ducks. Bottomland hardwood forests most often are found in the southeast Missouri lowlands.

Oxbow Lakes & Sloughs

These wetlands have open standing water less than seven feet deep and scattered aquatic plants, such as water lilies. They are found in the large river floodplains of the state and provide important habitat for fish, crayfish, turtles and water snakes. Great blue herons and egrets often hunt at their edges. These backwaters are important larval fish nurseries when they are connected to a river.

Riparian Areas

Throughout the Ozarks, spring-fed streams flow through a network of gravel bars, pools and riffles.

In a riparian zone extending from the main channel to about 50 feet on the land to either side of the stream, you'll find willows, sycamore, witch hazel and blue beech, along with water willow, mistflower, cardinal flower and, blue lobelia. Characteristic animals include belted kingfishers, river otters, Blanchard's cricket frogs and Fowler's toads.

Bottomland Prairies

These prairies are dominated by prairie cordgrass, or ripgut (named for its sharp leaf edges). These plants form a thick sod that covers terraces on floodplains above marshes in north and west-central Missouri. Bottomland prairies are subject to flooding, but standing water is present only briefly during the growing season.

In addition to flooding, bottomland prairies require periodic fires to prevent being overwhelmed by woody vegetation. Intermixed with the dense cover of cordgrass are sedges, milkweeds, wild iris and sawtooth sunflower. The northern harrier, western chorus frog, northern crawfish frog and grassland crayfish all use bottomland prairies.

Groundwater Seeps

The contact zone between different geological layers sometimes causes groundwater to well up and slowly percolate onto the land. Groundwater seeps are relatively rare and are most commonly found along the bases of hillsides in the Ozarks.

Because of the constant saturation of cool water, these groundwater seeps often have peat or muck deposits that build up over many years. In north Missouri there are a handful of saline seeps where salt-enriched groundwater bubbles onto land.

In the Ozarks, groundwater seeps may be called fens or acidic seeps, depending on whether their water chemistry is alkaline or acidic.

Fens receive alkaline groundwater that has flowed through calcareous bedrock, such as limestone or dolomite. Missouri's fens most often are found in karst landscapes of the Ozarks along with caves, sinkholes and springs. Sedges, bulrushes and wildflowers typically dominate fens. However, some fens have prairie plants, such as Michigan lily, and others have an overstory of trees.

Because of their cool and wet microclimate, fens often contain plants more typical of states to the north. Many of those plants are rare or endangered in Missouri. Plants characteristic of fens include sedges, swamp orange coneflower, golden ragwort, cowbane and grass of Parnassus. The rare four-toed salamander uses fens, as well as acidic seeps.

Where groundwater flows through sandstones, cherty gravels, sands, or igneous rocks, the seeps that develop are acidic. Acidic seeps abound in ferns and mosses and also have sedges and orchids. Acidic seeps are found throughout the Ozarks and along Crowley's Ridge in southeastern Missouri.

Adapting to Wetness

Plants living in wetland natural communities are adapted to deal with flooded conditions. For example, many wetland plants, including water lilies, have air pockets in their roots and stems. The pockets allow oxygen from the air to reach the plant's roots during flood conditions.

Many animals also have adapted to wetland environments. Ducks have an oil gland on their back that allows them to waterproof their feathers. Ducks also have special air sacs in their body to make them more buoyant.

The webbed feet of waterfowl allow them to swim, dive and cross mud. The feet of wading birds like herons and shorebirds allow them to cross mudflats without getting stuck. Amphibians and insects need wetlands for maturing their young.

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