Wolves were eliminated from Yellowstone National Park by 1926 and reintroduced in 1995. In their absence, elk populations had grown large enough to overgraze willow and aspen seedlings along stream banks. After wolves returned, elk altered their grazing patterns, avoiding the open valleys where they were most vulnerable. Riparian vegetation began to recover, and beaver populations, which depend on willow, expanded along previously denuded streams.
Which inference is most strongly supported by the passage?
- A
Riparian vegetation requires no protection from grazing
- B
Beavers compete directly with wolves for resources
- Ccheck_circle
The presence of a top predator can have effects extending well beyond its direct prey
- D
Elk populations are unaffected by the presence of wolves
Explanation
Wolves changing elk behavior, allowing vegetation recovery, and benefiting beavers shows cascading effects, supporting A. B, C, D contradict the passage.