Farmers and ranchers may not like wolves much, and they're still trying to shoot them in Idaho and Montana(and some idiot or idiots did in a whole pack that used to roam Yellowstone National Park. But they sure are good for the environments they exist in, whether the farmers, ranchers, and wolf haters know it or not. A recent study on Isle Royale, whose wolves are world-famous, seems to show that when wolves chow down on the local moose, they leave bits and pieces behind(not to mention wolf droppings, and such. And these "leavings" are apparently good for the local forests; the trees and other things there are healthier when there are wolves around, chowing down on their moose dinners.
Furthermore, this isn't the only time I've read about things like this. There are wolves on or near the British Columbia coast, that eat a lot of salmon, in the seasons when salmon mate and the runs are abundant. They just wade in and catch themselves as many salmon as they can eat, which is a lot easier than chasing down the "blacktail" deer(they're a subspecies of mule deer), and eating them. Of course, they have to compete with grizzly and "black" bears for the salmon, too, but there, the salmon runs are more abundant than here in the Puget Sound area(and a lot less full of pollution, too). The result of all these leftover salmon carcasses? Again, the forests where wolves leave their bits of salmon(helped by the various bears and perhaps other wild things as well) are a lot healthier than forests where there aren't any wolves. Which suggests that, indeed, contrary to the yowls of farmers and ranchers, wolves are, indeed a Good Thing.
Just an addendum here: I believe the wolves of this part of British Columbia, are classed in the same subspecies as the two packs that wandered into Central and Eastern Washington, and settled in to raise families. There probably aren't many migrating salmon any more, in the nearby streams, but there are plenty of mule deer. So the wolves doubtless eat them. And are probably, even now, starting to make the forests healthier. Which is a good thing, because there are people in those areas whose incomes partly derive from those forests. Even if the local farmers and ranchers don't like this, the presence of the wolves, in the long run, may be healthier for all.