The different prairie types are the result of variations in soil moisture, soil composition, geological substrate, glacial history and topography. Dolomite prairies occur where the glacial debris is thin, and the dolomite bedrock is at or near the surface of the soil. These areas have a high magnesium content in the soil due to the weathering of the exposed dolomite bedrock. The extra magnesium favors a unique plant community, many of which grow nowhere else. Dolomite prairies may be found along the upper Illinois River in northeastern Illinois, where the plants grow in dolomite bedrock exposed by river erosion, and in a few other locations in northern Illinois.
What Lives Here?
Because the prairie ecosystem is recently evolved, few prairie species are restricted to the prairie habitat and may be found in other habitats as well. Plants tend to be more characteristic of specific prairie habitats than animals. Dolomite prairies support the growth of such plants as side-oats grama, prairie dropseed, Riddell's goldenrod, porcupine grass, prairie Indian-plantain, silky aster, hairy beardstongue, pagoda plant, slender sandwort and round-fruited St. John’s-wort. Animals and other organisms are typical of those found at other Illinois prairie locations.
hiking, wildlife observation, photography
Where is it Found?
Dolomite prairies may be found in northern Illinois, particularly along the upper Illinois River, where the plants grow in dolomite bedrock exposed by river erosion. A 1992 survey showed that only about 140 acres of dolomite prairie remain in the state and that most of these sites were very small in size. Below you will find a list of some dolomite prairies still found in Illinois. For many of these prairies, you will need to call in advance to make arrangements before visiting the site.
Colored Sands Bluff Nature Preserve near Shirland in Winnebago County; Douglas E. Wade Nature Preserve near Byron in Ogle County; Flora Prairie Nature Preserve near Belvidere in Boone County; Hanover Bluff Nature Preserve near Hanover in Jo Daviess County; Jarrett Prairie Nature Preserve near Byron in Ogle County; Lockport Prairie Nature Preserve near Lockport in Will County