Fish mismatch makes bears eat elk

摘要

In bringing lake trout to Yellowstone National Park humans may have inadvertently triggered a cascade of changes with consequences for migratory elk.A team led by Arthur Middleton, then at the University of Wyoming in Laramie, looked at the long-distance effects of introducing lake trout to the park in the western United States. The lake trout have caused a marked decline in native trout and, unlike the natives, the interlopers spawn on lake bottoms — out of reach of grizzly bears.