The impact of wolves on Canadian ecosystem
Loss of wolves changes Canadian ecosystem – study
By Maggie Fox, Health and Science Correspondent
WASHINGTON (Reuters) - The loss of once-plentiful wolves in a part of
Although scientists have long noted that the loss of even one species can have profound effects, the report is one of the first large-scale studies to show clearly the widespread consequences of losing a predator at the top of the food chain.
Mark Hebblewhite of the
Wolves were driven out in the 1960s "because that's what we did then," Hebblewhite said.
"The first wolf pack recolonized the Bow Valley of Banff National Park in 1986. High human activity partially excluded wolves from one area of the
The wolves clearly had a major effect on elk. Elk populations were 10 times as high in areas where there were no wolves, Hebblewhite's team found.
This meant that elk could be found in suburban backyards, and sometimes on hiking trails.
"Seven people are sent to hospitals every year on average by getting into a fight with an elk," he said. "They are
The elk browsed on tender young willows, leaving little for beavers and willow-dwelling birds. Aspen trees seemed less affected.
"We also found that as elk populations climbed, active beaver lodges declined, probably because beavers could no longer find sufficient trees with which to build their dams," Hebblewhite said in a statement.
But in the parts of the park where wolves returned, the elk populations in affected areas fell and willows were coming back.
While other predators such as grizzlies might have played a role, Hebblewhite's team noted, bears were never completely driven from the park while wolves were.
"Yes, wolves are ecologically important. It (the study) bolsters the importance of conserving species like wolves and other top carnivores," Hebblewhite said.