Saving an icon: Huxley's David Wallin working to restore mountain goats to the Cascades

Whither the mountain goat?

A variety of reasons -- from past hunting pressure to impacts on winter habitat -- exist to explain why mountain goat populations in Washington state's Cascade Mountains have declined for most of the 20th Century. After hunting pressure was reduced in the 1980s, two of the main herds in the state -- the Mount Baker group and the group in the Goat Rocks Wilderness Area between Mount Rainier and Mount St. Helens -- appear to have recovered and now are stable.

The reduction in hunting hasn’t, however, helped goat populations recover in historic areas such as the mountains near Darrington, which once held thriving goat herds. Moreover, genetic analysis of goats throughout the Cascades indicates very limited movement among populations, especially between populations in the north and south Cascades. This limited movement can lead to a loss of genetic diversity and reduced survivorship.

Western Washington University professor of Environmental Science David Wallin has received a pair of grants from The Mountaineers Foundation and the Washington Department of Fish and Wildlife to continue his work researching the regional decline of the state’s population of mountain goats in the Cascades.

He says that understanding why these goats aren’t mixing comes down to a simple, basic answer: the I-90 corridor.

“People tend to think, ‘How can goats be in trouble? All the alpine habitat is protected,’ and that’s true for half the year, when they are in the high alpine zones. But the other half of the year, they come down into valleys that are much more developed,” he says. “But the biggest factor leading to isolation of mountain goat populations in the Cascades is that I-90 basically walls them off from each other. Because the two small groups are so isolated physically and genetically, it makes them much, much more vulnerable.”

The richness of genetic variation that comes from groups being able to interbreed -- in the large herds in British Columbia’s Coast Range, for example -- has been shown to add up to 15 percent to the likelihood of a goat living until its second year, and given that anything over a 1-percent harvest due to hunting has been shown to cripple a herd’s survivability, that extra 15 percent becomes an ever larger number for biologists.

“It’s simply critical that we find out more about how we can get these groups together. This summer, we’re going to be looking at the in-state herds but also a similarly isolated herd in southern B.C. in the Princeton/Penticton area and some populations in the Coast Range and Canadian Rockies. We hope to see how -- or if -- these groups are able to interbreed and how that success or failure is affecting their survivability,” he said.

Wallin's grants pay for one graduate student and as many as five undergraduate interns who will do the field work in the high alpine zones, collecting genetic material and mapping the goat populations.