Biologists are developing a deeper understanding of how the terror felt by prey creates a major — and greatly under-appreciated — behavioral dynamic that ripples through all kinds of ecosystems. By Jim Robbins, April 11, 2017, Yale Environment 360.

“…The 1995 reintroduction of wolves to Yellowstone National Park led to seminal research on the ecology of fear, with the wolves altering the feeding behavior of elk and touching off a cascade of ecological effects on vegetation and other wildlife. In recent years, researchers like Zanette have developed new approaches in hopes of creating a deeper and more nuanced understanding of the role of fear, given how important it is to understanding ecosystems. Yellowstone, meanwhile, continues to provide new insights into the ecology of fear on a large, wild landscape. The topic raises important conservation questions. As predators have declined globally, their disappearance — and the fear factor they induce in prey — has had knock-on effects in numerous ecosystems. Can a decline in biodiversity brought about by a lack of predators be restored by bringing them back?

“It underscores the importance of protecting intact populations of predators,” says Larry Dill, an emeritus professor of biology at Simon Fraser University who studied similar dynamics in marine ecosystems. “Without healthy populations of wolves and sharks you have impacts all the way down the food chain.”