Final answer:
The return of wolves to Yellowstone National Park dramatically affected the abiotic environment by altering elk behavior, leading to vegetation regrowth, reduced erosion, and improved fish habitat, showcasing the importance of a keystone species.
Step-by-step explanation:
The reintroduction of wolves to Yellowstone National Park in 1995 had a significant impact on the abiotic environment of the region. As wolves preyed on elk, they altered the elk's foraging behavior, leading to decreased grazing near streambanks. This change allowed for the regeneration of vegetation such as willow and cottonwood, which helped to reduce erosion and provide better habitat for fish and other species. The growing vegetation also contributed to improved conditions for other species, like the beaver, which benefited from the habitat change. This example clearly demonstrates how wolves, as a keystone species, have a profound effect on their ecosystem, influencing both the biotic community and the abiotic environment.