As the Flathead National Forest begins to draft an updated Forest Plan, John Weaver, a noted biologist with the Wildlife Conservation Society, is making the case for adding more than 400,000 acres of designated wilderness to the plan.

Weaver argues that because of its location along the Continental Divide and its great diversity, the Flathead Forest is “one of the most important forests in the United States.”

He recently completed a 154-page document called “Conservation Legacy on a Flagship Forest: Wildlife and Wildlands on the Flathead National Forest, Montana” to make his case.

Wilderness is needed to preserve populations of fish and wildlife species like bull and westslope cutthroat trout, mountain goats, grizzly bears and wolverines, he writes.

Weaver created a “vulnerability profile” for each species, arguing that motorized use, human disturbance and other factors, such as climate change, threaten each of them.

“We know that roads can have a myriad of effects on these species,” he said last week. “In some cases, wilderness is the last refuge for these species.”

He also describes changes to connectivity, arguing that as climate change impacts the West, one way species will adapt is by moving through the landscape to find suitable habitat.

Trout may need to move upstream to find colder waters, and grizzly bears may need to move across mountain ranges to find sufficient food sources.

“Highways, roads and human settlements fragment intact landscapes,” he says in his report. “These fracture zones can disrupt wildlife movements, leading to smaller and more isolated populations “

Weaver’s wilderness recommendations exceed those by the Montana Wilderness Association and the Whitefish Range Partnership.

The latter, a collaborative group of North Fork stakeholders, came to an agreement calling for about 83,000 acres of additional designated wilderness in the North Fork.

Weaver says that figure should be closer to 138,000 acres.

Weaver also recommends wilderness in the Middle Fork, along the Swan Crest, in the South Fork near Bunker Creek and in the Swan Range adjacent to the Bob Marshall Wilderness.

The biologist said the Flathead Forest has a long history of conservation, from the creation of the Bob Marshall Wilderness 50 years ago to the Montana Legacy Project in the Swan Valley that was established several years ago.

“Successive generations of citizens and government leaders have worked hard to safeguard the rich tapestry and health of the Flathead,” he said. “Now changing times require leadership anew.”