Illinois’ Grand Prairie: Protecting and Re-creating the Tallgrass Ecosystem

The great tallgrass prairie once covered 22 million acres in Illinois. Within that large ecosystem, known today as the Grand Prairie Natural Division, were dry and wet grasslands, sedge meadows, prairie groves with trees, sand savannas, wetlands and other natural communities. More than 300 species of plants, 60 mammal species, 300 bird species and 1,000 insect species have called this division their home over the millennia, according to the Grand Prairie Friends, a volunteer-driven, not-for-profit, conservation organization and land trust composed of people who share a commitment to preserve and restore tallgrass prairie and woodlands in east-central Illinois.

Nearly all of the original tallgrass prairie is gone now, swallowed up by agriculture and development. But vestiges of the former beauty of the prairie state still remain, with remnants, restorations and reconstructions at public properties such as the state-owned Goose Lake Prairie State Natural Area, the federally owned Midewin National Tallgrass Prairie and The Nature Conservancy’s Nachusa Grasslands. True remnant, intact prairies can be found in small spaces including old pioneer cemeteries as well as hill prairies that were too steep to plow or to put cattle on.

Volunteers, landowners and scientists are working to save, enhance and reconstruct grassland ecosystems in the Grand Prairie Natural Division. This, the largest natural ecological division in Illinois, encompasses most of the state north to Ogle County, south to Shelby County, west to Henry County and east to the Indiana border.

It is here where early settlers wrote about the grasses higher than their heads and wildflowers of varying colors and heights blooming spring through fall. They also encountered woodlands near rivers where water stopped the natural fires that spread across the grasslands.

The Illinois Department of Natural Resources (IDNR) is among many entities working to save the remaining prairie remnants, and restore and reconstruct prairies where feasible. Their actions include prescribed burns, removal of invasive species and new plantings. In addition, bison, which historically dominated the Grand Prairie and browsed the grasslands, have been reintroduced to the landscape at Nachusa Grasslands and Midewin National Tallgrass Prairie.

“We have such little high-quality prairie left in Illinois, less than one-tenth of 1 percent of the original tallgrass prairie,” said Eric Smith, a District Natural Heritage Biologist with IDNR who works throughout the Grand Prairie Natural Division. “It’s the job of the IDNR Division of Natural Heritage to maintain remnant high-quality prairies.”

The state also uses the Illinois Wildlife Action Plan written in 2005, and updated in 2020, for the approval of the U.S. Fish and Wildlife Service. The plan’s intent is to research and implement what Illinois can do to keep species on the landscape from becoming threatened or endangered.

“If we want more pollinators, we need more prairie,” Smith said. “If we want area-sensitive grassland birds, such as northern harriers that were once really common in the Grand Prairie, we need large treeless expanses of grasslands.”

Goose Lake Prairie State Natural Area (Grundy County) is being maintained as a natural tallgrass prairie. Enough land exists there for hunting, wildlife viewing and hiking, Smith explained.

“Goose Lake Prairie a great place for the public to visit and imagine what a significant portion of the Illinois landscape looked like thousands of years ago,” Smith said. “You can get a sense of the expansiveness of the prairie at Goose Lake, and also witness wet prairie and shallow marsh habitats contained within the prairie. It has a lot of endangered plants (once common) and the tall grasses pioneers talked about that rubbed up against the belly of their horses.”

Goose Lake Prairie harbors numerous species of animals that require tallgrass prairie ecosystems to thrive, for example, Henslow’s sparrow and rare turtle species.

To appreciate the wide diversity of plants that grew in the historic prairies, Smith recommended visiting prairie cemeteries.

“Prairie cemeteries are postage stamps of what the large, expansive prairie landscape looked like,” he said. Prairie cemeteries were never plowed or disturbed, except to bury people there. Each has different dominant plant species, and many have dozens of plant species crammed together, as they were in the original prairie.

One of Smith’s favorites is Weston Cemetery Prairie along Route 24 in McLean County.

“In the spring, visitors can see birdsfoot violet, hoary puccoon, golden Alexander, and, my favorite, shooting stars, which seemingly number in the thousands,” Smith said.

Forests that pocket the Grand Prairie Natural Division were maintained along rivers that stopped natural wildfires. A floodplain forest at Allerton Park in Monticello is one such remnant of a historic riverine forest. At Allerton, the native Virginia bluebells bloom in profusion in early spring.

Another forest type in the Grand Prairie Natural Division is the grove, such as the prairie grove at Funks Grove in McLean County.

“At one time, this prairie grove covered as much as 3,000 acres,” Smith explained. “It is one of the state’s oldest forests, and an 18-acre tract that has been dedicated as an Illinois Nature Preserve.”

Also within the Grand Prairie Natural Division are regions dominated by sandy soils and scattered oak trees, which provide habitat for uncommon animals and plants including the slender glass lizard and the six-lined race runner. The state owns and manages some of these sandy regions for hunting and wildlife viewing, including the Green River State Wildlife Area, a mosaic of wetlands, sand prairie and savannah in Lee County.

Restoring grasslands and other native ecosystems within the Grand Prairie region, “do not yet match the full ecological complexity of the originals,” wrote James Krohe, Jr. in “The Heart of the Sangamon,” published by the IDNR.

But restored grasslands do provide habitat for rare birds, such as bobolinks, short-eared owls and Henslow’s sparrows.

And Krohe wrote: “Restoring wetlands within the region also has expanded habitat for amphibians, birds and reptiles.”

Smith agreed.

“Ecology is a relatively new science,” he said. “We can do some things that make restored areas look similar to the original tallgrass prairie, but there’s a lot we still don’t know.”

That is why the IDNR and other land management organizations continue to research, re-create and restore Illinois’ ecological past.

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Sheryl DeVore writes environment and nature pieces for regional and national publications and has had several books published, including “Birds of Illinois” co-authored with her husband, Steven D. Bailey.