Paul Vahldiek had plenty of questions when he first heard about the wolf evidence on the ranch. Would wolves shrink his prized elk herd, which attracted so many of his clients? Would they unsettle his cattle, and lower their birthing rates? "I didn't wake up one morning and cheer and say, 'OK, wolves!' " he says. "But it's the hand we're dealt. And if they help the land be healthier, I'm for that."

His neighbors may not share his equanimity. Though surveys indicate widespread support for wolves among Coloradans in general -- the most recent, a 2001 poll funded by foundations and conservation groups, found that well over 60 percent of Southern Rockies residents even supported deliberate wolf reintroduction -- ranchers and other rural residents are not as enthusiastic as city dwellers. Even some staff members at the High Lonesome Ranch are less than thrilled about the possibility of wolves in the area.

Scientists and managers who work with wolves often remark on the uniquely powerful human responses, both positive and negative, that the animals provoke: "Wolves make people absolutely nutty," says Ed Bangs. "You get all the pro-wolf people saying, 'God, we're finally saved, the ecosystem is in balance,' and you get the other side saying it's proof that Satan has returned to Earth."

But on the ranch, as the evidence of wolves emerged, the science proceeded calmly. Eisenberg continued to visit and develop a final plan for her research, and she sought the advice of Michael Soule, a well-known conservation biologist and the president of the nonprofit Wildlands Network. Soule, whose angular features and grave manner belie a healthy sense of humor, calls wolves an "inexpensive and practical tool" for restoring ecosystems and improving their resilience to climate change. He envisions corridors of public and private protected areas throughout North America, including along the spine of the Rocky Mountains, that would aid the restoration and conservation of ecosystems and their keystone species, including large predators. When Eisenberg told him about the High Lonesome, he visited the place for himself, and presented the Wildlands Network vision to Vahldiek.

"I thought it was a brilliant vision, a necessary vision," Vahldiek says now. "Did I think it was achievable? Not initially. My first thought was, 'Let's bring reality into the equation.' "

In January 2009, at the invitation of the Wildlands Network, Vahldiek attended the Western Conservation Summit, a gathering of conservation leaders in California. "So here I was, this hunter, this rancher, this duck out of water, kind of sneaking around," says Vahldiek. He mostly listened for two days –– "not an easy thing for me to do," he admits with typically self-deprecating humor. During the conference, he spotted a six-foot-high wall map of the Wildlands Network Spine of the Continent conservation initiative, and he located his ranch.

"On the scale of that map, the High Lonesome -- well, I don't think it was as big as a half dollar, but it was bigger than a quarter," he says. "I thought, 'Dang, well, I'm a butcher's son from south of Houston, and with people's belief and help, I put a quarter-plus on this map. And there are millions of people and organizations out there that work towards conservation. If I could put down a quarter, why couldn't other people put down half dollars, or dimes, or nickels, if they thought it was going to make the world and wildlife a better place?'

"At that point," he says, "I didn't think it was so silly anymore."

Vahldiek is now a board member of the Wildlands Network, and Soule serves as an unpaid science advisor to the High Lonesome Ranch. Vahldiek emphasizes that he and his partners are more interested in conservation than profit. "None of the partners need anything to be sold or done on this ranch to complete any financial planning," he says. "They're more concerned about how to care for it into perpetuity."

Vahldiek hopes that recreation, ranching and other enterprises on the ranch will support conservation for the long term, and he's confident that his partners and heirs will continue to protect the land. But the ranch, it's worth remembering, is no national park: There are as yet no guarantees of protection for posterity -- the partners are considering conservation easements, but have not yet put any in place on the main ranch properties. And as on most private lands, much of the decision-making power rests, for good or ill, in one set of hands.

Eisenberg and Vahldiek, during a conversation about their collaboration, say the needs of science and the demands of landownership have, so far, coexisted peacefully. Vahldiek smiles and adds, "Well, you know, Cristina doesn't get a vote." Eisenberg smiles at the joke, which, of course, is not really a joke. The High Lonesome Ranch, with or without wolves, is a landscape controlled from the top down.

During a few short, sunny days in December, the Vahldieks come to the ranch to discuss research, conservation, and wolves with Eisenberg, Soule and state wildlife officials. In two days, despite a raging head cold, Paul will fly to the Bahamas, where he and one of the High Lonesome partners recently bought a three-mile-long island off Grand Bahama called Deepwater Cay -- a historic bonefishing resort that Paul also plans to manage, like the ranch, for conservation. "That was the one place we used to actually go and relax," says Lissa with amused dismay. "Now, it's work, and we're walking around with clipboards."

But business, for the moment, has been set aside, and Lissa, Eisenberg and Soule walk along a quiet, snow-covered dirt road, toward a stand of aspen near where the first wolf-like scat was found.

This stand looks more vigorous than many on the ranch, with small aspen trees scattered among the larger trunks. It appears that few aspen sprouted here between 1920 and 1995, but then young trees began to spring up, Eisenberg says. And she wonders: Why is this stand apparently healthier than so many others on the ranch? Could mountain lions, whose populations rebounded in Colorado in the 1970s as hunting regulations took effect, be hunting here now, protecting some of these young trees from hungry elk? Does the eradication of wolves help explain the 75-year lack of new growth?

Eisenberg hopes to answer such questions by studying the patterns of predators and prey on the ranch, and examining the relationships of those patterns with aspen growth. Any effects of returning wolves on elk and deer, and in turn on aspen, won't be evident for years. For now, she will continue to gather data, and ponder the ecological influences of predators -- including the visitors from the North.

"Aspen are complicated," says Soule with a smile, calm in the knowledge that scientific questions always create more questions.

The return of wolves to this valley, and to the state of Colorado, raises the most complicated questions of all. But Soule, as he surveys the vast ranch landscape for signs of predators, remains serene.

It feels wonderful," he says. "I'm not frightened at all."

Michelle Nijhuis is a contributing editor of HCN. Her work appears in The Best American Science and Nature Writing 2009, edited by Elizabeth Kolbert.

This coverage was funded by High Country News Enterprise Journalism Fund contributors and by a grant from the David and Lucille Packard Foundation.