Lessons from the Wolf

Lessons from the Wolf (Scientific American: 24-May-04)
Bringing the top predator back to Yellowstone has triggered a cascade of unanticipated changes in the park's ecosystem.
The changes might have been unpredictable, but they can't have been unanticipated: reintroduce a top predator, and the ecosystem is bound to change. In fact, the scientists who reintroduced the wolves to Yellowstone made pretty accurate predictions about the effect.