The enormous decline of large, apex predators and "consumers" ranging from wolves to lions, sharks and sea otters may represent the most powerful impacts humans have ever had on Earth's ecosystems, a group of 24 researchers say. The decline of such species around the world is much greater than previously understood and now affects many other ecological processes through what scientists call "trophic cascades," in which the loss of "top down" predation severely disrupts many other plant and animal species.

Source: Loss of large predators disrupting multiple plant, animal and human ecosystems