Lake St. Clair Coastal Habitat
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Pottowatomi Prairie, Walpole Island First Nation

Photo: Suzan Campbell

Grasslands are covered with grasses, sedges, and wildflowers and have less than 10 percent of their area covered by woody species. They include managed landscapes, such as parks, golf courses and cemeteries, pasture and fallow fields as well as natural habitats such as prairies, meadows and fens. The habitat value of these lands varies tremendously; old, neglected cemeteries often function as refugia for prairie plants, and fallow fields may have considerable habitat value for wildlife, but the mowed lawns of parks and golf courses have little to offer.

Native grassland communities such as lakeplain prairie are among the region’s rarest, and are considered globally imperiled. Historically, Wayne, Macomb and St. Clair Counties had over 60,000 acres (24,281 hectares) of lakeplain prairie. Today, less than 1,000 acres (405 hectares) remain in Wayne and St. Clair Counties. In Ontario, similar losses have occurred, with less than 1 percent of the original prairie cover remaining. Lakeplain mesic sand prairie is the upland form of this grassland community but there are also two wetland forms - lakeplain wet prairie and lakeplain wet mesic prairie. Another similarly related habitat, lakeplain oak opening, is considered an upland deciduous forest community. These grassland communities provide habitat for Henslow’s sparrow and tall green milkweed.

While a few rare species can only survive in native grasslands, many others can persist in a wider range of grassland types. Ring-necked pheasants, for example, are surprisingly common in the unmowed vacant lots of Detroit. With the decline in agriculture in the area, however, cultural grasslands such as hayfields and pastures are disappearing rapidly. Grassland quality is not the only factor affecting habitat suitability; for many vulnerable species, area is a critical factor. Species such as bobolink, savanna sparrow, Henslow’s sparrow and upland sandpiper are most likely to occur on parcels larger than 140 acres (57 hectares). In a fragmented landscape, these parcels are increasingly rare, and will not persist without deliberate planning.

Within the project area, grassland has increased from about 54,500 acres (22,055 hectares) in 1995 to about 58,000 acres (23,471 hectares) in 2000, an increase of 7.1 percent. The majority of this increase is due to agricultural fields that have been taken out of cultivation.

For more information, see: Coastal Habitat Asessment, Section IV (PDF)