Some good news for wolves in the west. As I reported in Tuesday’s Sightline Daily, there’s evidence that a second breeding pair of gray wolves has shown up in Washington State. Last summer, biologists confirmed the first wolf pack in Okanogan County—the first breeding pair to be found in the state since the 1930s. Another pair might now be residing in Pend Oreille County.
With loaded claims coming from both sides of the reintroduction debate, it was nice to see some good, science-based reporting from the Billings Gazette this morning (more coverage of the study here). A study by Montana State University takes a look at the wolf-elk relationship that’s developed in the Greater Yellowstone area, where wolves were successfully reintroduced in the mid-90s.
After reintroduction, elk populations dropped from around 18,000 to around 6,500. This year, the numbers are slightly over 7,000. Various explanations were given, from drought to over-hunting, but wolf predation on calves was seen as the most likely cause. However, the new study says scat evidence and radio-collar tracking shows relatively few elk calves have been killed by wolves.
The real culprit?
In the absence of wolves, elk migrated down to large meadows where they could forage on grass throughout the winter. Reintroducing wolves forced the elk into the mountains, where scarce food (elk that could graze without the presence of wolves ate 27 percent more food) isn’t enough to keep pregnant elk healthy—and fewer calves were born as a result.
Certainly, wolf predation is a factor—but it can’t account for the entire drop in Yellowstone populations; reality is a bit more complicated. Changes in nutrition, brought on by the presence of wolves, were an unexpected but significant factor. The author of the study says it’s hard to tell if wolf/elk populations have reached an equilibrium, or entered a cyclical relationship—in which case current elk populations could rise for a time.
The moral of the story? Since wolves were eradicated from many of the western states nearly a century ago, local ecosystems have seen some dramatic changes—from inflated elk populations to changing riparian zones. As Northwesterners move forward bringing wildlife populations closer to historic levels, we’ll see some exciting—and possibly unexpected—transformations in Cascadia’s natural heritage.