Wet Prairie and Fen

A wet prairie, or wet meadow, has moist to saturated soils with standing water present for only brief to moderate periods during the growing season, more than 50 percent of the vegetation being herbaceous and a neutral pH. A fen is a type of wet prairie formed where water bubbles through limestone and is deposited at the earth’s surface at a water source, such as a spring or seep. Calcium and magnesium are in abundance in the soil at a fen resulting in an alkaline pH and giving rise to a variety of unique plants adapted to surviving these conditions.

A wet prairie contains a wide variety of herbaceous species including sedges, rushes, forbs and grasses. Woody vegetation, if present, accounts for less than 30 percent of the area. Tickseed sunflower, straw-colored flatsedge, wild millet, winged loosestrife, wild blue iris, swamp milkweed, swamp rose, white lady’s-slipper orchid, ferns, cordgrass and water hemlock are all plants that may be found in a wet prairie. Historically these areas contained many birds including ducks, geese, swans, rails, prairie-chickens and cranes. Turtles and frogs were common, too. Fens also are comprised mainly of herbaceous plants, although woody shrubs or trees may be present. Fen vegetation includes New England aster, white turtlehead, shrubby cinquefoil, hoary willow, pitcher-plant and skunk cabbage. Animal species are similar to those living in a wet prairie.

hiking, wildlife observation and/or photography

Wet prairies were once common in the northern two-thirds of Illinois in river and stream floodplains. Today, few of these areas remain. They were often associated with other wetland types, especially at the fringes of a lake, pond or marsh. Many wet prairies were partially drained and farmed. Matanzas Prairie in Mason County, Green River State Fish and Wildlife Area in Lee County, Goose Lake Prairie in Grundy County and Chauncey Marsh in Lawrence County all have remnants of wet prairies. Fens are most often found in the northeast corner of the state and in isolated areas along the Illinois River valley. Turner Lake Fen in Lake County, Spring Grove Fen Nature Preserve in McHenry County and Ferson’s Creek Fen Nature Preserve in Kane County are all sites with a fen.