By 1925, the last wolf pack in Yellowstone National Park had been killed by park wardens as part of a policy to eliminate all predators.
It seemed like a good idea at the time. Take out the predators and let nature flourish. Except that’s not what happened.
In the 70 years of the wolves’ absence, the entire Yellowstone ecosystem fell out of balance. Coyotes ran rampant while the elk and deer population exploded, overgrazing willows and aspens. And without those trees, songbirds began to decline, beavers could no longer build their dams and riverbanks started to erode. Without beaver dams and the shade from trees and other plants, water temperatures were too high for cold-water fish.
So in 1995 wolves were reintroduced into the park to reduce the elk and deer population amidst much controversy. Tourism operators feared the wolves would attack tourists and bring visitors numbers to a halt. But that’s not what happened.
Instead the elk and deer populations started diminishing immediately. Within 10 years, willows rebounded. In 20 years, the aspen began flourishing. Riverbanks stabilized and fish thrived. Songbirds returned as did beavers, eagles, foxes and badgers.
The wolves also killed coyotes. Which led to more rabbits and mice which means more hawks, badgers, weasels and foxes. There’s also more carrion lying around to feed bald eagles and bears.
The beauty of unintended consequences.