In Yellowstone, the reintroduction of gray wolves to the park in 1995 set off a trophic cascade, affecting many different species, ultimately changing abiotic factors in the park. All of the options below describe changes caused by the return of the gray wolf
population except:
Populations of elk were driven down by predation
Trees and brush populations rebounded from predation pressure from herbivores,
Nesting bird populations increased due to increased habitat availability
Beaver populations changing, adding to the shift in water flow through the park.
All of the above were true effects of the reintroduction of wolves.