A Predator's Return
U scientists were thrilled when they spotted wolf pups at Cedar Creek Ecosystem Science Reserve. But with the wolves came promises and perils.
The first time University of Minnesota ecologist Forest Isbell saw the wolves, it was a crisp and sunny Monday morning in May 2015, and he was sitting in the passenger seat of a pickup truck. At the wheel was Jim Krueger, the building and grounds supervisor at Cedar Creek Ecosystem Science Reserve—a 5,600-acre wildlife oasis located 35 miles north of Minneapolis and one of the U’s primary natural laboratories for long-term ecological research.
The previous weekend, Krueger had spotted half a dozen wolf pups in a grassy field in the middle of the reserve. When Isbell heard about the sighting, the ecologist asked Krueger to drop everything and take him there. Neither expected to see the wolves out in the open.
But after driving on a dirt road most of the way around the field, Krueger stopped the truck. Beneath a pine tree about 15 feet away were eight adorable wolf pups, tumbling over each other. Isbell, whose research has long focused on plants and soil, was so enamored of their playfulness that he says he felt like a kid again.
“I’ve never seen anything like it,” says Isbell, a soft-spoken native of northern Iowa, whose two young children fight over the family’s one wolf stuffed animal. This was the first time in at least 100 years that a wolf den had been spotted so close to the Twin Cities; it was little more than a half hour’s drive from the metro.
Right away, Isbell began to dream about the research possibilities. The arrival of the wolves in Cedar Creek would offer an opportunity to study basic yet poorly understood questions around what happens to a landscape when top predators return. “I’ll be honest,” says Isbell, who now leads a team of five researchers studying the wolves of Cedar Creek, “the wheels started turning immediately in my mind.”
Next, he started to wonder—and worry—about the people living near Cedar Creek in the adjacent city of East Bethel. As wolves have been expanding into new territories around the world, they have been causing trouble for humans. In the months after the den was discovered, the new arrivals were suspected of killing two dogs and a calf. People complained, and federal trappers euthanized most of the wolves, including the Cedar Creek breeding pair and some of their year-old pups. At least one wolf still visits the reserve on a regular basis.
Now, as Minnesota’s protected wolf population continues to grow and expand, Cedar Creek researchers are waiting for more wolves to arrive. In the meantime, they are also exploring ways to keep the peace, including educational efforts to help neighbors protect their animals from wolves. If they can pull it off, the achievement will attract international attention. “We expect the wolves will continue to come back,” Isbell says. “If they don’t cause trouble, we may be able to learn to coexist with wolves in this part of the state.”
The Cedar Creek Ecosystem Science Reserve doubles as an environmental enclave and a field station, cramming all of Minnesota’s major ecosystems into nine square miles of grasslands, oak savannas, bogs, and more. There is one big lake, a few smaller ones, a creek, and a few trails that offer access to the public. But most of the reserve’s pines, cedars, and maples remain off limits to all except gophers, eagles, bears, deer, otters, and fishers—and the scientists involved in the longestrunning ecological study in the world.
Since the 1940s, University of Minnesota researchers have mined Cedar Creek for data, measuring everything from rainfall and rodent density to sapling growth and rabbit numbers. It’s an unrivaled wealth of information. “We have more data of what’s going on in the last few decades in Cedar Creek than literally anywhere else on Earth,” Isbell says, adding that the reserve was the site of the very first biodiversity study in the world. That kind of long-term information offers a unique opportunity to look beyond year-to-year variability and instead connect dots between trends, adds ecologist Meredith Palmer, a U of M postdoctoral researcher who has worked in Tanzania, South Africa, and other countries with the U’s lion researcher Craig Packer. “Cedar Creek is bursting at the gills with data,” she says. “It’s a data set people dream about.”
At least until 2015, eight decades’ worth of data from Cedar Creek had been collected in the absence of wolves. Members of the dog family, wolves were once widespread across the continental United States, including in Minnesota. But hunting, habitat destruction, and a federal poisoning program pummeled their populations throughout the early 20th century. By the 1950s, Minnesota’s wolf numbers had declined to fewer than 750. Most lived in the northeast corner of the state.
Gray wolves were listed as endangered under the Endangered Species Preservation Act in 1967. After a brief delisting, they regained threatened status in Minnesota, Wisconsin, and Michigan in 2014. Those protections allowed them to rebound. By 2017, according to the Minnesota Department of Natural Resources, Minnesota was home to more than 2,800 wolves. And as their populations have grown, they have moved farther south and west. Since the 1990s, packs of wolves have lived near Lake Mille Lacs, about 65 miles north of Cedar Creek, with lone wolves occasionally wandering toward the Twin Cities. The 2015 den was a sign that wolves were comfortable enough to settle close to the metro.
Luck is only part of the reason that wolves wandered into such a well established outdoor laboratory, says Nancy Gibson, cofounder of the International Wolf Center in Ely. Young wolves typically strike out in search of new territories, and Cedar Creek offers a protected landscape full of deer and other prey. Her hope is that the return of wolves to the area will help restore an elusive balance between predators and prey, potentially controlling problems ranging from Lyme disease to deer caused crop damage. “You have to remember, these animals evolved together,” Gibson says. “When you have an ecosystem that doesn’t have a predator around, it might be fine for humans. But it isn’t fine for the habitat.”
Nobody expects Minnesota to return to what it was before the wolves disappeared from the region a century ago. But Cedar Creek researchers are eager to see what will happen next. Isbell has set up a grid of more than 100 thermal, motion-sensing trail cameras. Fences have been erected so the team can compare landscapes with and without predators or prey. And, accompanied by U of M wolf expert David Mech, Palmer plans to lug buckets of wolf urine and scat into the reserve to see how prey react to signs of a predator they may not have encountered in decades.
Based on her work in Africa, Palmer is prepared for the unexpected. When lions were reintroduced to reserves after a long absence, she says, the “landscape of fear” had been disrupted, and some prey populations didn’t seem to know how to protect themselves. Nobody is certain whether Cedar Creek’s deer and other potential wolf prey will act similarly unfazed, or if they will alter their movements, in turn affecting the plants they eat and the entire ecosystem.
Equally uncertain is how attitudes will evolve within adjacent communities, says Isbell. On a cold April afternoon in his office on the St. Paul campus, he scrolled through images of Cedar Creek’s inaugural wolf pack, captured by trail cameras in May 2016. For him, it was a sad day when trappers came and took the wolves away. Now, his team is partnering with the International Wolf Center to communicate with neighbors and increase the possibility for interspecies acceptance. “Most Minnesotans like wolves, but most don’t like to live close to wolves,” Isbell says. “Whether we can coexist has yet to be seen.”
Emily Sohn is a freelance journalist in Minneapolis whose stories have appeared in the Washington Post, Nature, bioGraphic, and other publications.
Photos courtesy Jacob Miller