Wolf‐triggered trophic cascades and stream channel dynamics in Olympic National Park: a comment on East et al. (2017)

Abstract

East et al. (2016) concluded that long-term channel widths and braiding of Olympic National Park rivers were significantly influenced by peak flow magnitude and were inversely associated with a slow decline in the abundance of Roosevelt Elk (Cervus elaphus) over a period of 65 years. We consider some of their results and conclusions to be in error since the effects of highly altered riparian plant communities, effects that began after the extirpation of gray wolves (Canis lupus) in the early 1900s and which became increasingly severe during the remainder of the 20th century, were largely ignored or misrepresented. Overall, we conclude that the evidence provide by East et al. (2016) does not diminish the importance of trophic cascades whereby the loss of an apex predator allowed a native large herbivore to increasingly alter riparian plant communities over time, thus contributing to increased channel widths and braiding of the park's rivers.