Presenter (Christopher Brown): Hello and welcome to “The real world”, our weekly programme about nature. My name is Christopher Brown, and today we travel to the western United States, to Yellowstone National Park. With me today is Dr. Catherine Smith, a professor at Montana State University and an expert on the history and development of Yellowstone.
Christopher Brown (CB): Good morning, Dr. Smith. Can you tell me a little bit about Yellowstone National Park?
Catherine Smith (CS): Good morning, and thank you for inviting me. Yellowstone is the nation’s oldest national park and was established shortly after the end of the Civil War, when Ulysses S. Grant was President. The park is located in three states, Montana, Idaho, and Wyoming, and covers almost 9,000 km2. The park is probably best known for its geysers—those hot springs that eject lots of water and steam, and its wildlife. The park has large populations of bears, bison, elk, and importantly, wolves.
CB: Why are wolves so important?
CS: Wolves are a vital part of the Yellowstone ecosystem. You know, not so long ago there were no wolves in the park at all.
CB: None at all? How’s that? I thought wolves were all over this part of the Rocky Mountains.
CS: You’re right, wolves have always lived in this area. But by the 1920s, most had been killed by hunters. People often think of the mass shootings of American bison because of Hollywood movies, but in fact wolves were hunted with more determination than any other animal in American history. Officially, the last wolves in the park were killed in 1926.
CB: And what has happened since then? How did wolves come back to the park?
CS: Well, in the 1940s and 1950s, biologists began to realize that the absence of wolves was a problem. The elk population began to increase tremendously, because wolves are natural predators of elk and without them, the elk multiplied.
CB: Why would an increase in the population of elk be a problem? I mean, elk are native to this area too, aren’t they?
CS: Yes, of course, but scientists saw that there were too many elk for the habitat. Yellowstone has long, hard winters, with lots of snow. Without the wolves, the elk did not need to move around very much to look for food because they were not being threatened. So the elk stayed in places with lots of young trees and branches that were above the snow, and ate them—they browsed, as we biologists say—and as a result, certain types of trees would no longer grow in some areas because the elk had eaten all the young ones. And this was devastating for beavers, which depended on those branches to survive during the winter. The elk had eaten them all.
CB: There was a problem with beavers, too? I thought that the beaver population was stable after people stopped wearing beaver coats and hats.
CS: Well, ecosystems are incredibly complex. Beavers were disappearing from Yellowstone because their food supply was limited since the elk ate so much. Today the beaver population is growing, and beavers are building new dams and and ponds all over the park. The park is experiencing much less erosion and plant loss. And one of the main reasons for the increase in the number of beavers and plants is the Yellowstone Wolf Project.
So in essence, are you saying that the wolves saved the beavers and trees? Could you tell us a little more about this project?
Sure. In the 1990s biologists in Yellowstone began exploring the idea of bringing Canadian wolves to the park. In January 1995, the first eight wolves arrived from Alberta, Canada. Today we have about a hundred wolves. About 10 years ago we had a peak of 174 wolves, but in the past ten years some hunting has been permitted because wolves were no longer classified as an Endangered Species. The wolf population is stable now.
It sounds like an interesting project. Was everyone in favour of it? I mean, in the western part of the United States there are a lot of ranches with cattle, and wolves are known to attack cattle. I can imagine that the ranch owners were not too happy.
In fact, this project has been called the most controversial project in the history of the U.S. National Park Service. Depending on your point of view, the revival of wolf populations in Yellowstone is either one of the greatest wildlife restoration projects ever undertaken, or the worst idea that the government has ever had for ranchers and hunters. It’s a real source of debate here. A 2010 study by the U.S. Department of Agriculture showed that only a little more than 2% of cattle deaths were caused by predators. In fact, government studies have shown that between 1991 and 2005, coyotes, dogs and mountain lions, not wolves, were the main killers of cattle.
And how do you feel about the project? Now that you’ve been able to see and study the consequences over twenty years, would you do it again?
Absolutely, reintroducing wolves to Yellowstone has been very successful. Most scientists agree that a wide diversity of species is a healthy thing for the larger community of animals. The return of the wolf has helped other animals to thrive. Bears, coyotes, foxes, and even birds like eagles eat carcases. All those meat-eaters benefit from the protein the wolves leave on the landscape. We have more trees than 20 years ago. And the increase in beavers has helped the rivers. So in my opinion, the project has had a very positive impact.
Our time is up for today. Thank you, Dr. Smith, for joining us today on “The real world”.
My pleasure
Adapted from an article by Kate Tobin on the PBS News Hour https://www.pbs.org/newshour/science/wolves - greenthumbs - yellowstone .