“Where winter wolves bark amid wastes of snow and ice-clad trees.” (Whitman, Walt. “Song of Myself.” 1855.)
For almost eighty years wolves were absent from the Cascade Mountains. In 2008, gray wolves began recolonizing the northwestern United States and reestablishing packs in Washington. Five years later, the University of Washington and Washington Department of Fish and Wildlife along with support from SCI Foundation, launched a predator-prey study to explore the ecological impact of recovering wolves.
The majority of research on wolves has been conducted in protected areas such as the famous Yellowstone National Park. The Washington Wolf Project is different, with a study area in a landscape managed for multiple uses that include hunting, logging, livestock, and high human population densities.
Predator-prey dynamics vary over time, and so far the recolonizing wolves have not been shown to negatively impact ungulate populations. The University of Washington’s work has focused on the impacts of wolves on both white-tailed deer and mule deer, two important game species. Support from SCI Foundation was used to deploy GPS collars and innovative collars attached with cameras, in order to more accurately study the ecological impact of returning gray wolves to the Pacific Northwest. SCI Foundation grants have allowed the project to be maintained for five years now, and are the basis for three PhD student researchers.
The Washington Department of Fish and Wildlife’s objective is to maintain sufficient numbers of mule and white-tailed deer while allowing the natural recovery of wolves in the interest of the Washington public. Data from 120 total collared deer and a system of trail cameras show some interesting results on survival, habitat use, and sources of predation.
The predominant predator was actually found to be cougars, the source of more than half the investigated deer mortalities. This result compares to what was learned in the Montana Bitterroot Elk Project, where mountain lions continued to be the dominant predator in areas with recovering wolf populations. Contrary to previous research on competition between coyotes and wolves, in Yellowstone National Park for example where reintroduced wolves drove out coyotes with drastic implications for the greater ecosystem, in Washington coyotes are still responsible for significantly more mortality than wolves. Wolves represented less than 10% of total deer mortality, followed lastly by black bears.
Surprisingly, wolves do not have an additive impact to the existing predation pressure. The reason why may have to do the study area’s managed landscape. Here, wolves are sparsely distributed relative to protected areas, with low pack size and avoidance of human features. High human mortality of deer may be a more important driver of population trends.
The presence of wolves may still be influencing deer with non-consumptive effects such as costly anti-predator behavior, increased vigilance, and altered foraging patterns or habitat use. Further research is needed to quantify the cumulative impact. Results of the Washington Wolf Project are expected to be published in the next year, with a final report by the end of 2018.
With lots of suitable unoccupied habitat remaining for wolves in western Washington, we can expect to see the population to continue to increase. There are now over seventy wolves across the state. Results of this project do not support either increased wolf management at this time or adjustment of human harvest, given the evidence that wolves do not have an additive effect. Once delisted, wolf management options will likely expand.
The project team has also developed videos for increasing public understanding of the conservation and management of wolves. Public opinion on wolves has ventured out of the realm of folklore and into the reality of science. The local response to the new wolves has been overwhelmingly positive.
In addition to presentations given to the public, this project was covered in a PBS documentary titled, “The Ecology of Fear”, featuring principle investigator Dr. Aaron Wirsing. The educational program has continued to engage students and local youth through volunteer opportunities. With the help of the Predator Ecology Lab, Washingtonians are learning what the return of the gray wolf means to them, their home state, and the Cascade Mountains ecosystem.