In my opinion the wolves did not restore Yellow Stone’s ecosystem. Before they were introduced in 1995 the wolves had been absent for 70 years. In this amount of time Yellow Stone went through major changes, some that are irreversible. Arthur Middleton from the Yale School of Forestry and Environmental Studies denies the claims saying that wolves are solely responsible for bringing life back to Yellow Stone Park. The main source to support his argument is the experimental studies on willow plants found by the Colorado State University. After humans drove away the wolves Elk took over and grazed on the shrubs until they were all but gone. “Without willows to eat, beavers declined, without beaver dams, fast-flowing streams cut deeper into the terrain. The water table dropped below the reach of willow roots, now it’s too late for even high levels of wolf predation to restore the willows” (Did the Reintroduction of Wolves Truly Change Yellowstone?, Candice Gaukel Andrews). Elk numbers have declined but wolves are not the only predators responsible. “Human hunting, growing bear numbers, and severe drought have also reduced elk populations.” Also trout numbers have been declining forcing bears to find new sources for food, Elk. Other sources, such as the videos from George Monbiot, state that Elk stayed away from areas in the park that were dominated by wolves allowing the vegetation to grow. This is partially true as they avoided a few areas, however they still mostly went and grazed wherever they pleased. The wolves did not have as big of an impact on the Elk as many often claim. Overall there were many other more important factors that led to the re-growth of Yellow Stone besides the wolves.