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

willows
willows

bears
bears

elk
elk

wolves

Answer 1

The correct answer is wolves.

Wolves are considered a keystone species because their presence and hunting behavior significantly affect the populations and behaviors of other species in the ecosystem. Their reintroduction led to a series of changes that benefited various other species, demonstrating their crucial role in maintaining ecological balance.