This VIDEO mentions something really important. We still have wolf culls like that in Nolo, ID “to protect the elk herd.” The idea is to cull the local wolves down to 20 or 30 individuals, so as to build up the local elk herd. It's called the ecology of fear hypothesis.
Predators do play a role in ecosystems. And they don’t just do it through killing prey species. They also do it by making the prey species fear predation.
And that fear has real ecological ramifications.
Yellowstone says hunt changes protect park wolves http://www.scoop.it/t/biodiversity-is-life/p/933229392/yellowstone-says-hunt-changes-protect-park-wolves