TAILIEUCHUNG - Stephens & Foraging - Behavior and Ecology - Chapter 13

13 Foraging and the Ecology of Fear The reintroduction of wolves in 1995 changed Yellowstone National Park. Riparian habitats have seen a marked increase in willows and aspen. The streams running through these willow thickets meander more. Wetlands have reappeared. | Illllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll 13 Foraging and the Ecology of Fear Joel S. Brown and Burt P. Kotler Prologue The réintroduction of wolves in 1995 changed Yellowstone National Park. Riparian habitats have seen a marked increase in willows and aspen. The streams running through these willow thickets meander more. Wetlands have reappeared. Birds and butterflies have increased in the taller and more complex galleries along the riparian stretches and they breed more successfully than before. Can wolves really have such restorative power Wolves reshaped the Yellowstone ecosystem through their effects on elk. Without wolves elk could forage anywhere with impunity. They browsed their way through every aspen and willow grove and prevented regeneration. The riparian galleries gradually disappeared which in turn led to the near-extinction of beavers. Without beavers streams ran faster and eroded more and the marshy wetlands impounded behind beaver dams and diggings were lost. Things changed when the wolves came back. Of course wolves devour elk but much more importantly they scare them. Frightened elk spend more time vigilant and less time feeding. They bunch up more which lowers their feeding efficiency. Most of all fearful elk avoid dangerous habitats such as thickets. Frightened elk released the willows and the aspen which formed thickets with tall canopies that lllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll 438 Joel S. Brown and Burt P. Kotler created new habitat for birds and brought about a recovery of beavers and their activities. Streams slowed down and returned to their earlier meandering form. Fear can be a powerful ecological force. Introduction Predators kill prey. With this in mind Schaller 1975 in his classic book The Serengeti Lion documented just how many prey lions kill. Although lions kill large .

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