How the release of wolves saved Yellowstone National Park (2023)

When Yellowstone was declared the world's first national park on March 1, 1872, a signature of President Ulysses S. Grant protected two million acres of mountain wilderness, geysers, and dramatic, sweeping landscapes. However, it would not protect Yellowstone's wolves.

It may now seem difficult to understand how such a groundbreaking piece of conservation law could not protect the park's delicate ecosystem. In fact, the Yellowstone National Park Act of 1872 provided that the Secretary of the Interior "shall take precautions against the wanton destruction of fish and game found in said park." So you would assume that Yellowstone's thriving wildlife would have finally been in safe hands. But this was a time before biologists fully understood the interconnectivity of the great outdoors.

The missing link in Yellowstone's ecosystem was clear, and so it was that on January 12, 1995, wolves were reintroduced to Yellowstone, 69 years after the last known wolf pack was intentionally exterminated from the area.

Perhaps not enough attention was paid to the words of Scottish-American conservationist John Muir, the "father of national parks," when he wrote: "When we try to single out something for itself, we find it tied to everything else."

Wolves have been demonized ever since westward expansion in the 19th century first brought settlers and their livestock into contact with apex predators. Their critical role in the balance of Yellowstone's ecosystem has not been recognized, and thus their killing of prey (such as elk and deer) has been viewed as the "wanton destruction" of more prized species.

In the late 1800s, predator control was enforced in the park, including the poisoning of wolves. By the mid-1920s, over 130 wolves had been killed in Yellowstone National Park in the name of conservation, and the last wolf pack is said to have been killed in 1926. A survey of Yellowstone in the 1970s found no evidence of a wolf population at all - and over the years the absence of Yellowstone's top predator has devastated the entire ecosystem.

Without wolves, the moose population exploded. Moose were still hunted by bears and cougars (and hunted by humans) to some extent, but a lack of wolves meant numbers remained high enough to cause overgrazing of young willow, aspen and poplar trees, which in turn led to a decline in songbirds and beavers relying on grazing in winter. As beaver numbers declined, the lack of levees and shade meant that water temperatures rose and certain cold-water fish could no longer survive in Yellowstone.

Wolves have a rather amazing homing instinct, and it was feared that the first wolves would head north once released.

Wolf numbers declined in the 1900s. When the all-important Endangered Species Act was introduced in 1973, wolves were on the endangered species list. This meant that the U.S. Fish and Wildlife Service (FWS) had a legal obligation to restore endangered species where possible, but that plan was delayed by decades in the case of wolves. This is because the species has remained divisive among humans - and continues to do so today - over the belief that they pose a danger to us and livestock. In fact, unprovoked wolf attacks are incredibly rare andThe Guardian writesthat wolves "kill 0.2% to 0.3% of available livestock".

The missing link in Yellowstone's ecosystem was clear, and so it was that on January 12, 1995, wolves were reintroduced to Yellowstone, 69 years after the last known wolf pack was intentionally exterminated from the area.

First there were eight reintroduced wolves captured in Jasper National Park in Canada. By 1996 there would be 31 wolves captured in Alberta and British Columbia. Wolves have a rather amazing homing instinct, and it was feared that the first wolves would migrate north once released. To mitigate this, wolves were kept in acclimatization pens where moose carcasses were also planted to give them a taste of their new surroundings, but some wolves' instincts could not be overcome. Wolf number 10, the Alpha, was heading north on release and was shot illegally by a rancher in Montana. Rewilding is still a new, pioneering discipline, and the movement is learning with every project.

Wolf number nine, Wolf 10's pregnant mate, had followed the Alpha north shortly after, but luckily she was saved from harm. The bloodline of these two wolves can be traced back to the majority of today's Yellowstone packs.

The wolf reintroduction was part of a larger wolf program in the Northern Rocky Mountains, which also included reintroducing wolves in central Idaho and enforcing protection around recovering wolf populations in Montana. By 2002, the goals of the FWS had been met: There were 30 pairs of breeding wolves spread across three Rocky Mountain recreation areas.

The impact on Yellowstone National Park's biodiversity became apparent within a decade -- much faster than project stakeholders anticipated.

When the wolf was reintroduced in 1995, only one beaver colony remained in Yellowstone. There are now nine, with the expectation of more.

Willow stands were in poor condition due to overgrazing, but with renewed predation pressure from wolves keeping moose moving, grazing was no longer as intense and so willow stands became more robust – meaning they could once again host songbirds. Pastures are still recovering, but strong pastures also meant beavers had an ample food source. When the wolf was reintroduced in 1995, only one beaver colony remained in Yellowstone. There are now nine, with the expectation of more. As beavers spread, damming and building ponds, the trees thrived and cold, shady water returned to house fish.

In recent years, due to Yellowstone's lack of snowy winters, wolves have actually become the leading cause of moose deaths. Scavenger species that once relied on elk killed in winter can still thrive without snow thanks to elk being killed by wolves - benefiting ravens, eagles, magpies, coyotes and bears. Wolves also kill coyotes, increasing rabbit and mouse populations and in turn providing a broader food source for hawks, weasels, foxes and badgers.

25 years later, the reintroduction of wolves to Yellowstone is considered one of the most successful examples of reintroduction ever. A 2019 biological census recorded 81 wolves in nine packs. While the work is still ongoing - state laws still threaten wolves in some ways, ranchers still argue that wolves are too destructive and certain reports like to emphasize that while the wolves were important, they were one of several factors that caused the turnaround - it's a striking example of the impact one animal can have on an entire ecosystem; and a showcase of the cycle of life in action.

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