L. David Mech (“meech”) began his study of these animals at Purdue University as part of a project initiated by Durward Allen. The term “landscape of fear” was first used to describe effects caused by these animals. In a debated example of a top-down trophic cascade, these animals facilitated the recovery of riparian vegetation (10[1])such as willow (10[1])trees and cottonwoods. Introgression via interbreeding with a related species is a threat to reintroducing the extirpated “red” species (-5[1])of these animals in the southeastern (10[1])US. The oscillatory (10[1])population cycles of these animals and moose are studied in the world’s longest running (10[1])predator–prey study on Lake Superior’s Isle Royale. For 10 points, what keystone species and apex predator was reintroduced in the 1990s to Yellowstone (10[1])National Park? ■END■