He said he is surprised by how few studies show the impact wolves, bears and cougars have on elk, moose and deer populations. Instead, the largest driver of change in elk population numbers throughout the West is humanity.
“In most mainland systems, it’s only when you combine wolves with brown bears and have human hunting as a significant component that you see them suppressing prey numbers,” Wilmers said. “Plus, they’re mostly making noise in the background about how humans are managing their prey populations.”
In some studies, ungulate populations actually increased slightly in the presence of wolves and grizzlies, Wilmers said, possibly because human wildlife managers underestimated the impact of predators as they reduced hunting quotas.
Rae Wynn-Grant, wildlife ecologist and co-host of the television show, said, “This is a much-needed review, because it is well executed, and highlights areas where more research is needed.” Mutual of Omaha’s Wild Kingdom is protecting the wildin an email to Inside Climate News. Wynn-Grant was not involved in the paper, and her work was not part of its survey.
In their view, the paper showed that the increase of predators on the landscape does not automatically balance plant communities. “Our world would be much simpler if this happened,” she said, “but the evidence suggests that there are many variable factors involved in whether and how ecosystems respond to increases in carnivore populations in North America.”
Yellowstone, with its wide canyons, relatively easy access, and status as an iconic, protected landscape, has become central to scientists seeking to answer an existential question: Is it possible for an ecosystem that contains major carnivorous animals to be restored to their pre-extinction state upon reintroduction?
Wilmers doesn’t think scientists have answered that question yet, except to show that it could take decades to untangle the web of factors driving ecological change in a place like Yellowstone. When a predator is driven to extinction, it may be impossible to immediately reverse any changes that occur, he said.
Yellowstone’s alternative steady state trophic cascade was an issue echoed by researchers in both camps of the debate, and Wilmer believes it is important to understand when evaluating the tradeoffs of large-carnivore reintroduction.
“It is better to avoid the loss of beavers and wolves in the first place rather than accept that loss and then try to restore them later,” he said.
This story originally appeared on Inside Climate News.
<a href