He said he was surprised by how little research shows wolves, bears and cougars have an impact on elk, elk and deer populations. Instead, the main driver of change in Western elk populations is humanity.
“In most continental systems, it's only when you combine wolves with grizzly bears and remove human hunting as a significant component that you see them suppress prey numbers,” Wilmers said. “Beyond that, they are mostly background noise to how humans manage their prey populations.”
In some studies, ungulate populations actually increased slightly in the presence of wolves and grizzlies, Wilmers said, likely because wildlife managers overestimated the predators' impact by reducing hunting quotas.
“This is a much-needed review because it is well done and highlights areas where more research is needed,” said Rae Wynn-Grant, a wildlife ecologist and co-host of the TV show. Omaha Wild Kingdom Mutual Bond Protecting Wildlifein an email to Inside Climate News. Wynne-Grant was not involved in the paper, and her work was not part of its review.
In her opinion, the article showed that increasing the number of predators in the landscape does not automatically balance plant communities. “Our world would be a much simpler place if this were the case,” she said, “but the evidence suggests that so many variables influence how ecosystems respond to increasing predator populations in North America.”
Yellowstone, with its vast valleys, relatively easy access and status as an iconic protected landscape, has become a flashpoint for scientists trying to answer an existential question: Is it possible for an ecosystem that has lost its keystone large predators to be restored to its pre-extinction state once they are reintroduced?
Wilmers believes scientists haven't answered that question yet, only to show that it could take decades to untangle the web of factors that cause environmental shifts in a place like Yellowstone. Any changes that occur when a predator reaches the brink of extinction cannot be quickly reversed, he said.
Yellowstone's alternative steady state has been a view supported by researchers in both camps of the trophic cascade debate, and is something Wilmers believes is vital to understand when assessing the trade-offs associated with reintroducing large carnivores.
“It's better to avoid losing beavers and wolves in the first place than to accept the loss and try to recover them later,” he said.
This story originally appeared on Domestic climate news.
