By Joanna Lambert, Ecology and Evolutionary Biology Faculty Member and Environmental Studies Professor, University of Colorado Boulder
The most recent attempt in a decades-long endeavor to increase wolf populations in the Rocky Mountain states was the December 2023 reintroduction of gray wolves from Oregon to Colorado. In an interview with SciLine, Joanna Lambert, a wildlife ecology professor and the director of the University of Colorado Boulder’s American Canid Project, talked about the reasons for the reduction in gray wolf numbers in the United States as well as the benefits of restoring them to Western habitats.
Here are a few of the conversation’s highlights. Responses have been condensed and made clearer.
What effects might gray wolf population protection have on ecosystems?
Joanna Lambert: Predators in general, including apex predators, are vanishing from global environments.
Their prey species may grow excessively prevalent in the absence of apex predators. However, prey populations decline and vegetation may recover upon the reintroduction of apex predators. Because wolves were reintroduced in the 1990s, plant species like willow and aspen are now more common in several Yellowstone National Park ecosystems. Certain bird species may use the denser vegetation as nesting grounds, and beavers may find it easier to build dams, which may change the hydrology of rivers and streams.
These consequences are localized in Yellowstone. Remember that reintroducing wolves to Colorado encompasses a broad area—roughly 22 million acres of public lands—and that only 30 to 50 wolves will be introduced over the course of the next three to five years. Effects on flora and the overall population of prey species, such as elk, are therefore likely to be confined, dispersed, and limited to specific microhabitats in Colorado as well.
What makes Colorado’s reintroduction unique?
Joanna Lambert: This is the first time an organization other than the U.S. Fish and Wildlife would manage and return an endangered animal into its previous territory. Rather, Colorado Parks and Wildlife will handle this reintroduction. This is genuinely revolutionary and momentous in and of itself. This was the outcome of a citizen-led ballot initiative called Proposition 114, which was passed into law as of November 2020, rather than a federal level proposal.
In what way were the wolves brought back to the region?
Joanna Lambert: Skilled shooters and biologists operating from a helicopter in Oregon darted and immobilized those wolves. After being netted, they were taken on little aircraft and finally loaded onto cars that drove them to the areas where they were liberated. These animals will be closely observed for months or perhaps years after being radio collared. This winter, Colorado Parks and Wildlife hopes to release ten to fifteen wolves.
In what ways have gray wolf populations in the United States evolved throughout time?
Joanna Lambert: Scientists believe that there were between 500,000 and 2 million gray wolves roaming the North American continent prior to the advent of Western settlers more than 400 years ago.
There were only about 200 to 400 gray wolf mating couples in the lower 48 by the middle of the 1960s. This is mostly the result of numerous legislative bodies—local, state, federal, and regional—working together to eradicate predators. Wolves could be effectively reduced by hunting, shooting, trapping, and poisoning them.
By the time the Endangered Species Act was enacted in 1973, there were only a few gray wolves remaining after their numbers had drastically declined during the 20th century. In 1974, one of the first mammal species to be listed as endangered was the gray wolf.
Although they are confined in two groups, gray wolves have become more common across the United States. One is in Minnesota, Wisconsin, and Michigan in the upper Midwest, where there are perhaps 4,500 wolves.
There are most likely between 2,500 and 3,000 wolves in the Northern Rockies, which comprise the states of Idaho, Wyoming, Montana, eastern Oregon, and eastern Washington. The reintroductions that occurred in Yellowstone and Idaho in the mid-1990s are mostly responsible for these wolves.
How can gray wolves and humans live together?
Joanna Lambert: Humans have been living and surviving with gray wolves for thousands of years, so we do know how to get along with predators. This was true until about a century ago. The time has come for us to rediscover that knowledge and that information.
This can include a variety of hazing techniques or scare devices that can be applied to both predators and livestock. It may involve range riders making sure they are aware of the wolves’ locations. The way animals are herded up and moved is something that ranchers may alter. It will take time to implement these reforms, but Colorado Parks and Wildlife will be part of those discussions and help train ranchers to protect their livestock. The public education effort will also involve several nonprofit organizations.
How does the worldwide extinction crisis relate to this reintroduction?
Lambert, Joanna:We are in what many experts refer to as the sixth extinction, and in the coming decades, we could lose up to a million species. Globally, conservation biologists and practitioners are trying to counteract this significant extinction. One strategy that can be useful is the reintroduction of significant keystone species, such as gray wolves.
To learn more, view the entire interview.
The nonprofit American Association for the Advancement of Science hosts SciLine, a free program that assists reporters in incorporating experts and scientific data into their news reports.
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