Wolves were reintroduced to Yellowstone National Park in 1995. They began to hunt the abundant elk population, so elk numbers decreased. The elk carcasses provided food for other predators, like foxes, coyotes, and bears, so all of their populations increased. Elk used to overgraze on willow plants; now that willows are growing back, beaver numbers are increasing, because they prefer the slow-moving water that willows cause.

Question

Which of these species is a keystone species?
(1 point)
Responses

elk
elk
willows
willows
wolves
wolves
bears

Answer 1

The keystone species in this scenario is the wolves. Keystone species are those that have a disproportionately large impact on their environment relative to their abundance. In Yellowstone, the reintroduction of wolves helped regulate the elk population, allowing for the recovery of willow plants and subsequently affecting other species like beavers. Thus, wolves play a critical role in maintaining the ecological balance in the park.