Kankakee Sands: A Rare, Post-Glacial Ecosystem Thriving Near Chicago

But there’s another huge, sandy ecosystem nearby where unusual plants like wild lupine and rare insects like regal fritillary butterflies live. 

It’s called Kankakee Sands

Encompassing more than 20,000 acres, it spans the Illinois-Indiana border, mostly following the Kankakee River.

“Kankakee Sands is one of the most extraordinary landscapes in the Midwest,” says Jeff Walk, Midwest strategy director for The Nature Conservancy, which owns and manages land in this rare ecosystem. He calls Kankakee Sands a “living mosaic of rare sand prairies, wetlands and black oak savannas that support some of the region’s most-threatened species.”

Cindy Cain likens Kankakee Sands to the Galapagos in Ecuador. “It’s an ecosystem teeming with exotic diversity” right here in the heartland, says Cain, public information officer for the Forest Preserve District of Will County (FPDWC), one of many entities that own parts of the Sands.

Walk says collaboration with partners in Illinois and Indiana ensures that “iconic species such as the regal fritillary butterfly, the ornate box turtle and wild lupine can thrive in healthy spaces that benefit both people and nature.”

These parcels are separated by roads, farms and towns. “But they share the same geology and have similar native plant and animal communities,” says Juli Mason, director of conservation programs for FPDWC.

“The more these parcels are connected, the better it is for animals that require large home ranges, and the more populations can remain robust enough to survive disturbances,” she continues, mentioning species such as the Illinois-threatened ornate box turtle, which lives in open grasslands and sandy plains.

How it came to be

Kankakee Sands was formed after the last glacial era, some 19,000 years ago. As large sheets of ice retreated and melted, huge floods called the Kankakee Torrent covered the land that is now called Kankakee Sands.

“The result was sand deposits that got blown around in the wind and stabilized into the landforms we have today,” Mason explains. “These inland areas are lesser known than those along the Great Lakes. They’re older sand deposits, and over time they have been vegetated and stabilized.”

The term “Kankakee Sands” can be confusing, she says, since the entire region has that name as well as several preserves within it are owned by different agencies.

For example, KankakeeSands-Indiana consists of an 8,400-acre prairie and wetland, which connects with Willow Slough Fish and Wildlife Area, Beaver Lake Nature Preserve, Conrad Savanna Nature Preserve and Conrad Station Savanna.

Meanwhile, the KankakeeSands Preserve in Will County was added in the early 2000s and connects to the Illinois Department of Natural Resources’ nature preserve north of it called Wilmington Shrub Prairie Nature Preserve, also part of the region. Will County also owns high-quality nature preserves in the Kankakee Sands region, which it has protected for decades.

The Illinois Department of Natural Resources and Nature Conservancy Illinois also manage preserves that are part of what’s called Kankakee Sands-Illinois. One of these sites is the Pembroke Savanna Nature Preserve.

Pembroke features a rare black soil savanna, an ecosystem that once covered about 27 million to 32 million acres in the Midwest. By 1985, only 0.02 percent remained. Black oak savannas contain plants and animals found in both oak forests and tall grass prairies. This diversity includes flora and fauna that are listed as rare, threatened or endangered, according to the National Park Service. 

Some of the lands within the Kankakee Sands region are high-quality remnant ecosystems, says Mason. Others are agricultural lands that connect to the parcels, were purchased and are being restored. Restoration includes prescribed burning, redirecting water flow, removing invasive species and planting native seeds.

Such seeds were not easy to find, so the Kankakee Sands Native Plant Nursery and Greenhouse was created in Indiana, using seeds from plants growing in the high-quality remnants. “It’s a great source of seeds and they share that with us,” Mason says.

Native species and floral treasures

Regal fritillary butterfly. Photo courtesy of Dee Hudson/The Nature Conservancy.

It’s within these rare ecosystems that some of Indiana’s and Illinois’ rarest native species live. One of them is the Illinois-threatened and Indiana-endangered regal fritillary butterfly. From afar, a regal fritillary butterfly could be mistaken for a monarch,” says Alyssa Nyberg, native plant nursery manager and outreach coordinator for Kankakee Sands-Indiana. Both are large and orange, but the regal has smaller, dark hindwings that set them apart from the monarchs, she explains.  

The fritillary sips nectar from plants such as the wild lupine, which grows in Kankakee Sands. It also gets nectar from milkweeds and goldenrods, but the only plants upon which the butterflies will lay their eggs are certain species of violet, including birdfoot violet, arrow-leaved violet and lance-leaved violet—with birdfoot violet thriving in sunny, dry sites. 

Seeds from these species have been planted in the region, and the fritillaries are flourishing in some places. The butterflies also require native warm-season prairie grasses, which provide protection for them and their larvae.

Other unusual plants and animals within these reserves include orange-fringed orchid, endangered in Illinois and Indiana. This species grows in sand prairies and is considered one of the most stunning orchids in eastern North America. Each plant is bright orange and cylindrical, with 50 or more flowers ending in fringes.

This is not an easy plant to find in the Sands, but another one—the spotted bee balm, less rare—is easier to find and interesting to observe as native bees and butterflies sip its nectar.

The spotted is not the typical bee balm planted in gardens. Unlike most bee balm species with single flowers on each stalk, the spotted has tiny flowers stacked up the stem where large pink to white bracts (leaves that look like petals) radiate. It thrives in sandy or dry open areas in prairies, dunes and woodlands. Prickly pear cactus also grows in the Sands, blooming earlier in the season. Mason particularly likes the rare snakes and slender glass lizards found in the Sands region. “Glass lizards are tied to sandy areas and they’re pretty cool. They’re small and fast,” she says.

“The legless, little reptiles stay away from the sun when it’s hot, so the best time to find them is earlier in the day. Walk through dry sections and you might see them dart through open sand areas,” she suggests. The glass lizards are so named because their tails are easily broken; however, they can regrow them.

“At Kankakee Sands, it’s so exciting to see the restored areas develop and to see nature recover and respond,” Mason says. “Here you can feel the energy of the summer prairie, the birds, the insects, the plants. The wildlife energy is really high. It feels so alive, compared to what was once just a sterile ag field. That’s exciting.”

Sheryl DeVore has written six books on science, health and nature, as well as nature, health and environment stories for national and regional publications. Read more at SherylDeVore.WordPress.com.