Wolves, Elk, Bison, and Secondary Trophic Cascades in Yellowstone National Park

Yellowstone National Park's reintroduction of wolves in 1995/96 appears to have triggered a secondary trophic cascade, indirectly boosting bison populations by reducing competition with elk. Wolves predating on elk altered elk behavior and reduced their numbers, increasing forage availability for bison. This interaction highlights an alternative top-down pathway where predators influence multiple trophic levels by mediating competitive dynamics between prey species. The study suggests that while wolves and bison can have significant ecological impacts, the benefits of bison restoration may be constrained in areas with low predation pressure, high bison densities, or limited movement. These findings underscore the importance of considering cascading effects when reintroducing ecologically influential species.

Ripple, W. J., Painter, L. E., Beschta, R. L., & Gates, C. C. (2010). Wolves, Elk, Bison, and Secondary Trophic Cascades in Yellowstone National Park. The Open Ecology Journal, 3(1), 31–37. https://doi.org/10.2174/1874213001003030031