Revis Spring Hill Prairie Nature Preserve

Volunteers restoring a biodiverse hill prairie in Illinois

About Revis Spring Hill Prairie Nature Preserve

About Revis

Revis Spring Hill Prairie Nature Preserve, near Easton, Illinois, includes 412.7 acres along the south bluffs of Salt Creek. It is located in Mason County above the Sangamon River floodplain. This area contains the region’s highest hills, rising about 250 feet above the Sangamon River Valley. Home to many plants and creatures, it is an island of history and biodiversity. 

Open to the public, the preserve is marked by a sign, and there is a small sand parking lot. There is no water and no privy.  Deer hunting, which requires a site-specific statewide lottery permit, is allowed. Camping is not allowed. The site is monitored by IDNR.

Revis History

Revis Hill Prairie is a fragile ecosystem of loess, a loose, powdered loamy soil type. After the loess was wind-deposited on the terrain of what became southern Mason County, Illinois to form a low hill, it was subject to rapid erosion, and Revis Hill was dissected by ravines that drained into nearby Salt Creek.

The name – coming soon.

In 1973, the original 49 acres of Revis Hill Prairie Nature Preserve near Easton, IL was designated as the 45th Illinois nature preserve. In 1993, a substantial addition of land brought the total to 412.7 acres. 

It is currently one of the largest and finest loess hill prairies in the state of Illinois containing nearly 50 acres of Grade A or B loess prairie, according to the Illinois Natural Areas Inventory.

Revis is located in the Natural Division #4b, the Grand Prairie Division Springfield Section. This is the largest Natural Division in Illinois, making up much of the flat terrain common to central and east-central Illinois. The area was once dominated by extensive tallgrass prairie ecosystems, but most of it was converted for agricultural purposes. Some marshes and wetlands persist due to lack of natural soil drainage. The large size of the Natural Division supports diverse plant and animal wildlife.

Illinois Prairie History

Prior to European settlement, Illinois, the “Prairie State”, was covered in nearly 20 million acres of prairie, about 60% of the land.

In 1837, when John Deere invented the self-scouring, steel-bladed plow in Grand Detour, Illinois, it became possible to break the prairie sod and farm the prairie on a large scale. In a remarkably short period of perhaps 50 years, the vast majority of prairie in Illinois was plowed and converted to agriculture. 

Less than 2,600 acres of original prairie remain in Illinois. Of that, only 600 acres are hill prairie.

About Prairies

The word “prairie” is from the French word for a meadow grazed by cattle. Prairies are a type of grassland, a landscape dominated by herbaceous plants, especially grasses such as big bluestem and Indian grass as well as a large number of other species of grasses and wildflowers, the latter called forbs. Trees are either absent or only widely scattered on the landscape. 

Prairie vegetation sometimes reaches a height of 10 feet or more. When prairies were abundant, it was easy to get lost, since there were few trees or other natural features to act as landmarks. Even when on horseback, it was often not possible to see across the prairie to the horizon.

Prairie fires, started either by lightning or by Native Americans, were commonplace before European settlement. Any given parcel of land probably burned once every one to five years. These prairie fires moved rapidly across the prairie and damaging heat from the fire did not penetrate the soil to any great extent. Fire killed most saplings of woody species, removed thatch that aids nutrient cycling, and promoted early flowering spring species.

A considerable portion of the above-ground biomass of a prairie was consumed each year by the grazing bison, elk, deer, rabbits, and grasshoppers. This was an integral part of the prairie ecosystem, and therefore grasslands and hoofed mammals coevolved together. Grazing increased growth in prairies, recycled nitrogen through urine and feces, and opened up habitat for plant species that prefer some disturbance of the soil.

Prairie plants have adapted to these stresses by largely being comprised of herbaceous perennials with underground storage structures allowing them to survive from one germinating season to another, especially under unfavorable conditions such as drought or winter cold – growing points slightly below ground level and extensive, deep root systems. The tender growing points of prairie plants occur an inch or so below ground and are usually not injured by prairie fires or browsing animals. During droughts, the deep roots of prairie plants are able to take up moisture from deep in the soil.

What is a Hill Prairie?

A hill prairie is a specialized type of grassland ecosystem characterized by its location on steep, well-drained slopes, ridges, or hilltops.

Key characteristics of hill prairies include:

  • Topography and Location: They are typically found on steep, south- or southwest-facing slopes overlooking river floodplains, most notably along the Illinois and Mississippi Rivers.
  • Environmental Conditions: Often covered in wind-deposited silt, or loess, they experience significant exposure to the sun, frequent freeze-thaw cycles in the winter, and dry soil conditions that help prevent the encroachment of trees and shrubs that would otherwise dominate the landscape.
  • Vegetation: As a variant of the tallgrass prairie, these ecosystems are dominated by grasses, herbs, and shrubs rather than trees.

While hill prairies are most commonly associated with the Driftless Area and river bluffs in the Midwest, they also represent unique, isolated “islands” of native prairie habitat that have survived in areas where the surrounding land was either too steep or too difficult to farm.

Hill prairies develop on southwest-facing steep slopes where hot summer sun, dry winds and periodic fires keep forest species from growing there. Illinois currently has about 90 sites with good-quality hill prairies. There are about 530 acres of hill prairies (good and poor quality) in the state. 

Plants and Animals

Plants commonly found growing in Illinois hill prairies include little bluestem, daisy fleabane, side-oats grama, leadplant, green milkweed, silky aster, pale coneflower, prickly pear cactus, heath aster, horsemint, June grass and lousewort. The coachwhip snake, ring-necked snake, Great Plains ratsnake, prairie kingsnake and ornate box turtle are some animal inhabitants of hill prairies.

Loess

An impalpably fine and unstratified silt, known by the German name bess (or loess), lies on the older drift sheets near the larger river courses of the upper Mississippi basin. It attains a thickness of 20 ft (6.1 m) or more near the rivers and gradually fades away at a distance of ten or more miles (16 or more km) on either side. It contains land shells, and hence cannot be attributed to marine or lake submergence. The best explanation is that, during certain phases of the glacial period, it was carried as dust by the winds from the flood plains of rivers experiencing deposits of sediment that increase their elevation, and slowly deposited on the neighboring grass-covered plains. The glacial and wind-blown origin of this sediment is evidenced by the angularity of its grains (a bank of it will stand without slumping for years), whereas, if it had been transported significantly by water, the grains would have been rounded and polished. Loess is parent material for an extremely fertile, but drought-vulnerable soil.

Revis Revitalization Plan

While fire was a common occurrence in Illinois historically, it has largely been absent through suppression over the last 100-150 years. Native cedars, sumacs, and dogwoods along with invading shrubs like honeysuckle and autumn olive have taken advantage of the lack of fire on the landscape to close ranks on the hill prairies, robbing the prairie plants of much needed light. Now, many of our hill prairies are barely recognizable and a fraction of the size they once were.

Work is underway in Illinois to revive and restore hill prairies. Fire is being brought back to them. Shrubs are being cut. The prairies are starting to stretch back out on top of the bluffs. Many of the hill prairies on private and public lands are protected through the Illinois Nature Preserve System, while others occur in state parks and other public lands. 

Please check back. More information is coming soon.

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