Bringing bison back: Rewilding America’s heartland

FRANKLIN GROVE, Ill. — For the first time in almost two centuries, wild bison are roaming east of the Mississippi River.

Well, sort of. Even though the beasts have returned to northern Illinois, residents of Chicago should not expect to see them passing through the suburbs anytime soon. The bison were relocated to the Nachusa Grasslands, a conservation program dedicated to restoring Illinois’ native prairie, where they safely roam thousands of fenced-in acres.

“The idea of having bison at Nachusa has been around as long as the Nachusa project itself,” said Jeff Walk, the science director for the Nature Conservancy’s Illinois chapter. “They’ve been talking about this for 25 years.”

The 30 bison at Nachusa taken to Illinois at the end of last year are part of a regional trend: the rewilding of the Midwest. In recent years, conservation programs in several states in the region have reintroduced large mammals — such as black bears and elk — into areas they once inhabited, before they were hunted to the brink of extinction. In other places, species like wolves and mountain lions have naturally returned to their former habitats.

Bison are one of the United States’ most successful conservation stories, but they also exemplify just how much damage was done to the continent during westward expansion. It’s hard to know for sure, but at the beginning of the 1800s, Walk said, there may have been as many as 60 million bison in North America.

“And depending on the account, maybe there were 1,000 animals that remained after the great slaughter by the end of the 19th century,” he said.

Conservation efforts were largely concentrated in Western and Northern states, in some cases spearheaded by Native American organizations and governments. Today there are approximately 500,000 wild or near-wild bison in the United States.

Most modern bison contain varying amounts of cattle DNA after centuries of interbreeding, Walk said. The bison relocated to Nachusa are from a South Dakota herd with some of the least cow DNA found in any bison group.

“Most conservation herds have really small amounts of cattle DNA in them,” Walk said. “But we typically do not see very many bison that have obvious domestic cattle traits in terms of their coat color, for example.”

While domesticated bison raised for meat production have existed east of the Mississippi River, those now at Nachusa are the first near-wild animals in the region in nearly two centuries.

“We needed something to control the grass,” said Cody Considine, Nachusa’s chief ecologist. “Grazing was always the one thing that was missing here.”

Starting in 1986, the Nature Conservancy, an American environmental conservation organization, began buying land in northern Illinois to restore the state’s native prairie. Since then, the Nachusa Grasslands have grown to nearly 3,500 acres.

Although Illinois is nicknamed the Prairie State, native prairie makes up less than one-tenth of 1 percent of the land. “We’ve pretty much destroyed all of it,” Considine said. “You just wish someone could have spared a square mile of prairie, and unfortunately we just don’t have that.”

He added, “The state of Illinois prairie is very grim.”

But it is not without hope. For outsiders, the bison are interesting news. For those who have been involved in the Nachusa project, they are the last piece of a diverse ecological puzzle.

“It’s something very tangible you can see, but it’s definitely not the first animal study or population that we have at Nachusa,” volunteer Michelle Crites said of the bison. “It just happens to be big and fuzzy, and people like bison.”

The bison graze on fast-growing species of grasses, allowing other plant species to grow. The population of native dung beetles will increase as a result of the bison’s reintroduction, which will provide more food for the endangered box turtle population.

“All of a sudden, when we get a fuzzy animal, when we get a bison, the whole world cares,” said Crites, a 22-year-old Colorado State University student who has volunteered at Nachusa since she was in eighth grade.

The extra attention may prove beneficial for Illinois’ prairie conservation efforts. If the work at Nachusa can be replicated elsewhere, there may be hope for the state’s prairie yet.

“There still are species that are dependent on this habitat to live,” Considine said. “It’s our heritage, our culture, and we’re preserving and improving and increasing that at Nachusa. Bison just add to that restoration circle, if you will. It’s kind of the last piece of the puzzle of really having a full-functioning prairie.”

“We’re bringing back a big grazer,” said Bill Kleiman, director of the Nachusa Grasslands project. “I think it’s really important to try these things.”

Bison certainly wasn’t the only species devastated by westward expansion, and the Nachusa project was not the first conservation effort to restore the region’s large native species.

Starting in 1959, the Arkansas Game and Fish Commission reintroduced some 200 black bears to the state from Canada, and the population has grown to more than 3,000. Black bears have crossed the border and returned to neighboring Missouri.

Following Arkansas’ lead in another species restoration program, Missouri reintroduced 35 native elk to the southern part of the state a few years ago. After disappearing from the state around the end of the Civil War, the elk now number more than 100 and are reproducing.

“They’re only representing less than 2 percent of their native Missouri range,” said David Hasenbeck of the Missouri Department of Conservation. “The elk were located throughout the state of Missouri and were probably more numerous in different parts of the state, but given the way the population and the road networks and everything in Missouri, we located the elk in the most rugged, less populated, highest public land area in the state. And that actual elk restoration zone represents only 350 square miles.”

He added, “We do not intend to have elk statewide. We intend to have a population of around 400 elk.”

“I think there is clearly a lot of significant improvement that has happened in terms of restoring large species of wildlife that were lost from the Midwest,” Walk said.

Species have started to re-establish themselves naturally as well. Mountain lions are starting to appear in the Midwest once more, having been pushed almost exclusively to the Rocky Mountains by United States expansionism. The big cats are now seen more and more frequently in states like Missouri, Oklahoma, Illinois, Nebraska and Arkansas, according to a 2012 study published in The Journal of Wildlife Management.

After becoming a federally protected species in the mid-1900s, gray wolves have increased their numbers in northern states such as Michigan, Minnesota and Wisconsin. At the end of 2014, a federal judge put an end to gray wolf hunting in those states and placed the species back on the endangered species list.

“Part of that is changes in regulation,” Walk said of the various species returning to the heartland. “And part of it is those species adapting to people and those people adapting to the species.”