According to the video How Wolves Changed Rivers when the wolves came back it was both bad and good for the animals and people.First they hunted the elk and deer, because when the wolves were gone the elk and deer population grew too much. They grazed almost all the plants. When the elk grazed the willow the beavers started to decrease in population, because the willow is a major food and home tree. But when the wolves forced the elk to move they had to not graze the willow very much so more beavers came. Then more fish and water creatures came because beaver dams are there home and shelter. Also it gives shade for amphibians and more. After when the wolves hunted coyotes there was more mice and rabbits, so that meant more hawks and birds. There was more leftover meat from the new bears that had moved in, and even the rivers changed. The rivers changed because the trees stabilized dirt and soil so there was less erosion, the rivers started to meander less also they even created new water sources.