Paul Lister believes we’re all too obsessed with ourselves. “Most people’s philanthropic passions focus on humanity, rather than the fabric of where we live”, says the conservationist. “We give to healthcare, religion, the arts, but what would these things amount to if we don’t have oxygen to breathe?” Lister is one of Europe’s most vocal champions of rewilding, a movement that posits that predators and other keystone species are integral to maintaining the integrity of the ecosystems in which they’d naturally exist. In short, he believes we need to put the wild back into our wilderness.

The Englishman has been putting the concept into practice at Alladale, a 23,000-acre wilderness reserve in the heart of the Scottish Highlands. The Romans once referred to this landscape as “the Great Forest of Caledon”, but today, the Scottish countryside is characterised by barren highlands of heather and rock. Humans have manicured the landscape into one pretty garden, to the point where natural forests have disappeared, the soil is depleted, and large predators are now extinct. “The human assault on nature has been so sustained that wolves, wild boar, bear, lynx and other large carnivores that once roamed the forest are now only present in the fossil record”, says Lister. “You need all of these creatures to create balance in the ecosystem. When you take away predators, you are left with a total imbalance of species underneath.”

Since purchasing Alladale in 2003, Lister has set out to establish a new relationship with the natural world; one that isn’t solely extractive, but that leaves room for wilderness. His first initiative was to reinstate the old Caledonian pine forests – and to date, he’s planted 900,000 native trees, mostly Scottish pine, but also holly, juniper and birch. Next, he introduced wildlife, including red squirrels, golden eagles and pine martens.

His larger dream, to reintroduce predators, including bears and wolves, has been met with controversy. “I’ve been called ‘howling mad’ in the press”, he jokes. “Humans have a fear of wolves and bears, largely fuelled by fairytales and films. We have forgotten that we share this planet with other species. We can’t survive on this planet all alone.” Lister emphasises that he is talking about a controlled release, not releasing wolves into the countryside haphazardly. He believes that the reintroduction of predators will naturally control the deer population, and, in turn, enable the regrowth of forest. He also sees a great potential for tourism, citing the success of South African game reserves and America’s Yellowstone National Park.

After an absence of over 70 years, wolves were reintroduced to Yellowstone National Park in the mid-1990s. Since then, wolf-related tourism has been estimated to bring an additional $35.5 million annually to the surrounding local economies in Wyoming, Montana and Idaho. The land also naturally began to “heal” itself: deer numbers were reduced; plant life, relieved of the constant barrage of deer, started to recover; and as trees grew along the rivers, fish numbers rose.

Lister believes that through tourism, we can raise awareness of the urgency to protect wild places. Alladale, with its traditional Victorian central lodge and two cottages, offers guests the chance to cycle, hike, stalk deer and fish, but also view first-hand an ecological restoration. While the debate to reintroduce bears and wolves has been ongoing, Alladale has built a wildcat enclosure on the reserve, which currently houses four Scottish wildcats as part of a captive breeding project in partnership with the Royal Zoological Society of Scotland.

Next summer, the estate will host a pioneering citizen science research project led by Earthwatch Institute and the University of St. Andrews. Volunteers will be invited to help document the effects of Alladale’s ecological restoration, and will also help collect data to improve global awareness of the importance of rewilding ecosystems.

Lister’s rewilding efforts extend beyond the Scottish Highlands. In 2000, he established the European Nature Trust with a focus on environmental initiatives throughout Europe, but in particular, Romania, home to over half of Europe’s virgin forest and a high density of large carnivores including brown bear, wolf and lynx. Together with the Foundation Conservation Carpathia, the organisation hopes to form a national park that will be seen as the Yellowstone of Europe.

Lister isn’t alone in his dream of a wilder world: In northeastern Siberia, Russian ecologist, Sergey Zimov, and his son, Nikita, are trying to rewild the Arctic with a project called Pleistocene Park. The 50-square-mile nature reserve, named after the geological epoch more commonly known as the Ice Age, aims to resurface the Arctic belt with the huge swaths of grasslands that once existed even during this period’s deepest chills. The Zimovs have been stripping away the area’s trees and shrubs to make way for the return of an Arctic version of the African savannah, which research suggests will reflect more sunlight, causing the Arctic to absorb less heat and permafrost to melt more slowly, thus mitigating the effects of global warming. To grow their Ice Age lawn, the father and son have imported Pleistocene-era herbivores, including bison, reindeers and musk oxen, and are even working with researchers at Harvard University to introduce lab-grown woolly mammoth in the not-too-distant future.

In South America, Kris Tompkins, and her late husband Doug, saved 2.5 million acres of wild land and created five national parks. Since her husband’s passing in December 2015, Kris has dedicated herself to one of the largest rewilding programmes on the planet, bringing locally extinct species back to the parks. This includes the reintroduction of endangered animals such as jaguar, the giant anteater and the pampas deer. Tompkins has often said landscape without wildlife is just scenery, and she hopes national parks everywhere will embrace the responsibility of rewilding.

Lister says the Tompkins have been two of his greatest mentors in the rewilding movement. “Doug and Kris taught me that when it comes to conservation we need to think big”, he says. “We haven’t got a lot of time left. I want to be part of the solution, not the problem. For years, humans have seen nature as the enemy, but we need to live in harmony. I hope Alladale reminds guests that our past was once wild, and our future can be, too.”

Jen Murphy is a Colorado-based writer whose work has appeared in the Wall Street Journal, Outside, Men’s Journal and Departures.