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Tuesday, June 21, 2016

Nachusa: Fun People and Ornery Bison

One of the first of this year’s surprises came from the herpetologists and the ornithologists. To study reptiles, the herpers put out boards that snakes like to hide under, making it easier to find snakes by checking under boards. Sharing some of those boards are mice, which make nests in their shelter. The herpetologists reported that the mice have been making their nests of bison hair. Soon the reports came in that birds were also constructing nests with bison hair. “Where has this handy stuff been all these years?!” said the wildlife.  Indeed, bison hair is now ubiquitous, as are bison dung and bison trails – that lead to scattered plots of bison-grazed areas of shorter grass.

Nachusa Grasslands commemorated 30 thirty years of surprises on Saturday, June 17, 2016. There were speeches, music, potluck, and tours – but the greatest excitements swirled around the growing evidence that bison are changing the ecosystem.

A Return to the Pleistocene?

This year marks the first time that bison have inhabited a diverse eastern tallgrass prairie in well over a century. We are learning what nature was, long ago. In many ways, it’s a return to the Pleistocene[1].

Some people insist that conservation is about the past, before Europeans, or before people. That’s a superficial take. Nachusa suggests how profoundly conservation is also about the evolving present and, especially, the future.

When we walked over Doug’s Knob and saw a grazing bison bull, we were witnessing 
something both new and ancient. No scientist before now ever had a chance to study 
an eastern tallgrass prairie – one of the richest ecosystems on the planet – 
as it functions with its natural ruminant grazers.
Nachusa is beginning to look like Africa. We are remembering that North American nature for millions of years looked like what we now know mostly from the current haunts of rhinos, zebras, and Cape buffalo.

“The bison herd is spending most of its time in the old restorations,” said project manager Bill Kleiman. “Poor restorations are mostly just tall grass. The bison are busy changing that.” During the growing season, bison overwhelmingly eat C4 grasses[2]. Many rare wildflowers (and the butterflies, beetles, and other animals that depend on them) are thought to be dependent on grazers to regulate the grasses.

Nachusa has 120 different restoration patches, Kleiman said, because the volunteer stewards and staff have been rebuilding Nachusa diversely, patch by patch. These patches now have a surprising importance.

“One of the biggest impacts of the bison has been the arrival of the scientists,” said Conservancy biologist Cody Considine. Many major universities and individual scientists have applied for permits and begun research. One is using drones to evaluate vegetation changes through “light signatures.” Endangered turtles are tracked electronically. Each of the 120 differently restored patches represents a long-term experiment – now involving bison.
A potluck for volunteers, interns, and supporters celebrated 30 years of great surprises.
One speaker was Ralph Burnett, retired Conservancy real estate specialist. In 1986, Burnett had snatched the original 140-acres of Nachusa from a housing development auction. Nachusa seemed like Illinois’ last hope for a large grassland centered on remnant good-quality patches of prairie, oak savanna, and wetlands. Burnett out-bid the first few competitors with the today-puny price of $800 per acre. “How many of these plots do you want, Ralph?” asked the auctioneer. “All of them,” replied Burnett, and the auction was over.

In a year, Nachusa was 400 acres – in part because Burnett was busy finding people who shared the vision and who’d chip in funds for another parcel or two. By 1993, the preserve was 800 acres. But that was still too small for bison. Then board member John Santucci headed up a Conservancy board feasibility study. The board group travelled to states like the Dakotas and Nebraska where the Conservancy had been experimenting with bison preserves (on less fertile and much cheaper land). They reported back to the board that Nachusa bison were not only practical, but also a likely draw to more acquisition funding. Indeed, donor interest is another big change the bison have brought. The preserve is now 4,000 acres. A number of knowledgeable people said the long-term goal is now 10,000 acres. The dream advances.
Montessori for Adults

The bison fence and infrastructure cost more than a million dollars. The land cost many millions. But most of the restoration was planned and done by volunteers, in that expanding patchwork of 120+ small “artisinal” plots. Why not with big machines, by professionals? Says Kleiman, “This land gets better, more diverse, more natural results through the dedication and expertise of the Nachusa volunteers.” Staff and interns support the volunteers; they have the best equipment available for what machines can do. But the key is hundreds of species of rare seed – and sharp eyes that comb those plots for malignant species, weekend after weekend, year after year, because they’ve come to love the land and its people. (Some have been studying and working most weekends for years.)
Bison cows and young stay together all the time. They think as a group. Old bulls are ornery
and solo. Volunteers and staff plan together in the barn, upper right.
Nachusa is all about relationships.
Being interested in language, I asked volunteer Jeff Cologna what words he’d use to describe where this dedication comes from. He said, “Nachusa is Montessori for adults. There’s good leadership, but we volunteers are respected for our ideas and allowed to try, fail, succeed, and experiment with new approaches that may work better. Few supposedly creative companies are that good at bringing out the best in people.”

[1] Some people have criticized the restoration of the plains bison (scientifically speaking, Bison bison) to Nachusa as “unnatural.” The eastern tallgrass prairie had Bison bison grazing it only for only a couple of hundred years. Archeologists had wondered why they found no bison bones around Illinois’ Native American sites. But on the very oldest sites (10K+ years) they found the bones of different species of ancient bison (e.g. Bison latifrons and Bison occidentalis) along with mammoths and mastodons. With further study, a consensus developed that the eastern tallgrass prairie was so productive a habitat that populations of Homo sapiens rapidly became too great for the coexistence of the megafauna that had evolved here for millions of years without those crafty omnivorous humans. New to the continent at that time, people with large-mammal-hunting technology rapidly killed off the mammoths, Bison latifrons, and many others. Plains bison survived in their original habitat, the still-sparsely-inhabited western plains. Those bison that the first European explorers saw here had come east only after 1492 when European diseases began to reduce Native American populations drastically, some say by 90%. And then in the 1800s, those crafty omnivorous Europeans drove Bison bison back to the sparsely inhabited plaines once again.

Almost all the plants and animals of the tallgrass prairie are much older than a few thousand years. They didn’t live here when this land was under glacial ice, but they lived on prairies that retreated south. Species of bison and a large proportion of other tallgrass plant and animal species evolved over the 2.6M years of the Pleistocene. One study suggested that most grassland bird species today are a few hundred thousand years old – evolving from earlier forms. 

[2] C4 grasses changed the planet’s ecosystems and atmosphere.  Bison mostly eat C4 grasses – which have a much-improved ability to fix CO2 than earlier plants. They developed that C4 photosynthetic pathway 25 to 32M years ago during the Oligocene. But 6M years ago in the Pliocene, grasses increasingly 'emerged from the forest' to form major grasslands on all continents except Antarctica. Massive ruminant herbivores evolved to eat those grasses, making way for the Pleistocene (2.6M to 11K years ago), when the North American prairie experienced most of its evolution.

In North America, the major ruminant that survives is Bison bison. While C4 grasses are much more efficient at fixing carbon dioxide as plant matter, bison are especially good at turning that carbon back into CO2 and methane. But the grassland ecosystem banks most of its carbon below ground as roots and grassland soils. That cools the planet and may in part have been what those pesky glaciers were about. Stay tuned for more research on causes of cooling and warming over the next few decades. (Oops, is that soon enough?)

People find the bison a magical link to other worlds. Nachusa Grasslands is leading to important new science
and more profound understandings about people's relationship with nature.


  1. I am curious to know how less grazing tolerant species like eastern prairie fringed orchid and prairie lily fare under bison grazing at Nachusa. Prairie remnants have maintained diversity in the absence of bison. It remains to be seen whether the diversity of quality remnants will be maintained or degraded by Bison grazing at Nachusa. I think we will find that bison grazing has a place in restoration but is sometimes done in excess to the detriment of the ecosystem.

  2. A recent study at Land Between the Lakes in Kentucky found that bison basically eat grass, all grass, all the time. No forbs or woody species.

    1. I am sure that timing and stocking rate will be very important as it is with all grazers and browsers. The dynamic is very complicated and needs monitoring and study to make sure degradation is not occurring.

    2. Here is a blog post by Chris Helzer that discusses the difference between cattle and bison.

      In Chris' book, "The Ecology and Management of Prairies in the United States", pp. 121, he wrote, "Research has shown that forbs typically make up less than 10 percent of the diet of bison, as opposed to 10-20 percent for cattle. Chris then goes on to explain how cattle diets behave even more like bison under patch burn grazing management.