Hill prairies, comprised of a mixture of wildflowers, grasses and shrubs, occur on steep, southwestern-facing bluff systems, mainly along major river valleys. Growing conditions for plants are tougher here than elsewhere due to the intense sunlight, rapid drainage, and drying southwesterly winds, which prevail during the midwestern summers. Periodic fires are necessary to maintain the hill prairies; without fires, trees and shrubs take over from the prairie vegetation, despite the harsh growing conditions. This small, remnant hill prairie, shown in the photograph taken at Crevecoeur Nature Preserve, is burned off every few years; even so, the surrounding forest is barely being kept at bay. The Illinois River is just beyond the base of the river bluffs.
[Note: For an explanation of hill prairies, see the caption for Crevecoeur Hill Prairie.]
The Hopewell Hill Prairies occur within a thriving subdivision on the Illinois River bluffs. Because most of the homes occur on flatter ground, the remnant hill prairies that occur at the Village of Hopewell have been mostly spared from development. The prairie shown in this photograph is one of the best in the state, in terms of how the vegetation resembles what hill prairies were thought to be like before European-Americans moved into Illinois.
A trail leads to the top of this hill prairie from the visitor's center at Pere Marquette State Park, Illinois. On a clear day, one can see the arch at downtown St. Louis, Missouri, roughly 33 miles to the southeast.
A controlled, or prescribed, fire was conducted on March 23, 2010. The fire will help maintain this glacial drift hill prairie by discouraging encroachment of woody shrubs and trees.
This hill prairie lies on a terminal moraine from the Wisconsin Glaciation. Rocks were carried along in the ice from further north and then left behind when the glacier melted, some 10,000 years ago, more or less. After a fire, pebbles and larger stones can be seen embeded in the soil.
The small glacial drift hill prairie at Crevecoeur Nature Preserve was burned on March 30, 2010.
This toad has wedged itself between two layers of diamicton, a friable rock-like outcropping just below a small glacial drift hill prairie high above the Illinois River. Animals frequently excavate small caves in the crumbly material.
This glacial drift hill prairie is on a steep southwestern-facing hill side overlooking a forested ravine that drains into the Illinois River valley.
About 3 months following a prescribed fire, the hill prairie has responded favorably.
Revis Hill Prairie Nature Preserve overlooks the Sangamon River valley about 20 miles north of Springfield. This preserve protects one of the best complexes of intact hill prairie communities in the state.
Facing up the bluff side at Revis Hill Prairie, a high quality remnant of the natural Illinois landscape.
Revis Hill Prairie Nature Preserve in the far distance lies on the bluffs overlooking the broad floodplain of the Sangamon River (in the foreground).