Reintroduced carnivores' impacts on ecosystems are still coming into focus

""In most mainland systems, it's only when you combine wolves with grizzly bears and you take away human hunting as a substantial component that you see them suppressing prey numbers,""

""Outside of that, they're mostly background noise against how humans are managing their prey populations.""

""In some studies, ungulate populations actually increased slightly in the presence of wolves and grizzlies, Wilmers said, likely because human wildlife managers overestimated the effects of predators as they reduced hunting quotas.""

""Our world would be much simpler if it did," she said, "but the evidence suggests that so many variables factor into if and how ecosystems respond to increases in carnivore population in North America.""

Wolves, grizzly bears, and cougars rarely alone drive declines in elk, moose, and deer; human hunting and wildlife management are the dominant forces shaping ungulate populations across the West. Only where multiple large predators coexist and human hunting pressure is substantially removed do predators suppress prey numbers. In some cases, ungulate numbers rose slightly after predator returns because managers reduced hunting quotas expecting stronger predator effects. Increasing predator populations does not automatically restore plant communities, and ecosystem responses depend on many interacting variables. Restoring pre-extinction ecosystem states may take decades to evaluate.

Read at Ars Technica