Habitat Destruction
In the late 19th century and early 20th century, the wolves fed on deer and elk which people didn't like. So, because of this hunters were paid to kill the wolves and by 1926 the wolves were all gone. The park officials also thought killing them would help the elk and other big game animals. After this it caused a huge problem in the park. After the wolves were gone the population of elk became numerous. The number of coyotes also increased, they took over the land and the food that other small predators need to survive. The coyotes fed on newborn pronghorns and so year after year fewer pronghorns survived.The elk ate the young tree shoots and bark, few young aspens and cottonwood trees and willow shrubs survived to replace the old ones that died. The song birds there that lived and nested in those trees became rare. The beavers that needed the aspens, cottonwoods, and willows also began to disappear. Scientists thought that forest fires might fix Yellowstone but they were wrong. In 1988 there was a big forest fire which burned almost a million acres. They expected that shoots would grow from the roots of burned willows and aspens but the elk ate them instead. Scientist finally decided to return the wolves back to the park which helped fix the problems.