Study Warns That Forest Thinning Affects Lynx

By Beacon Staff

MISSOULA – A new study suggests that mechanically thinning old forests and clearing away deadfall creates poor habitat for the Canada lynx and its primary prey, snowshoe hares.

“There are huge gaps in our knowledge about this species, so our research is seeking solutions on how to manage them,” said John Squires, the study’s lead author and a research wildlife biologist at the U.S. Forest Service’s Rocky Mountain Research Station in Missoula.

The study, which is expected to be published in the Journal of Wildlife Management, found that the elusive lynx prefers to make its dens under downed logs deep within mature, dense forests.

Earlier research in Canada focused on the structure of lynx dens, but the new study explored the landscape surrounding dens in the contiguous United States.

Researchers followed 19 female lynx that used 57 dens on public and private lands in mountain ranges in western Montana between 1999 and 2006.

They counted the kittens, took genetic samples, and documented the dens’ locations and characteristics. The researchers also looked at ground cover, snowshoe hare populations, the proximity of roads, elevation and other factors in the surrounding areas.

“They’re all pieces of the puzzle,” said Nicholas DeCesare, a University of Montana graduate student and a co-author of the study.

The results show that 93 percent of the lynx made their dens under piled logs in drainage basins within dense, mature spruce-fir forests that hadn’t been logged.

A few dens were at the forest’s edge, but they also were protected by logs and dense cover. Forests that were naturally sparse or had been mechanically thinned were seldom used for dens.

In Canada, lynx and hare populations rise and fall together. But that cyclical relationship is not evident in the Lower 48 states, where both species are consistently sparse, according to the study.

The results come at a time when federal wildlife managers have proposed to dramatically expand the amount of critical habitat for lynx, which were listed under the Endangered Species Act in 2000 in the Lower 48 states.

The proposed critical habitat is in Montana, Idaho, Maine, Minnesota, Washington state and Wyoming.