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

wolves
wolves

willows
willows

bears
bears

elk

Answer 1

Wolves are considered a keystone species in this context. They have a significant impact on the ecosystem by controlling the elk population, which in turn affects the plant community and the overall health of the ecosystem. The reintroduction of wolves led to cascading effects that benefited other species and the environment, highlighting their keystone role.