A possible lawsuit in the Bitterroot National Forest is shining a spotlight on grizzly bears' most important habitat

A dispute is brewing in the Bitterroot National Forest over the impact the road less traveled is having on wildlife.

“Roads really impact grizzly bears. They are, in a sense, the main factor in determining whether or not an area is suitable as grizzly bear habitat,” Earthjustice lead attorney Ben Scrimshaw told MTN.

Bozeman-based law firm Earthjustice announced in mid-September its intention to sue the U.S. Forest Service over road design changes in the Bitterroot National Forest.

The notice alleges that a forest plan change approved last year violates the Endangered Species Act and endangers grizzly bears and bull trout. The notice, filed on behalf of conservation groups, said the change will lead to increased road construction and forest use, impacting habitat and disrupting species.

“Grizzly bears learn to avoid roads. “They can pass this avoidance behavior down through generations, and areas that should be important habitat for grizzly bears are made unsuitable by the presence of roads,” Scrimshaw said. “And on the other hand, there are also some bears” – it's less common, but it does happen – that they get used to roads and that's because they might find food along the road or, or something else. And this is an even more dangerous situation for the bear because they are then more likely to come into contact with humans, which often results in the grizzly bears being killed.

Although Mike Bader, an independent natural resources consultant and former Yellowstone National Park ranger, is not involved in the potential lawsuit, he understands why people are concerned. Because the Bitterroot National Forest, like the Lolo National Forest, lies between important bear recovery areas, Bader said it is extremely important to the health of the grizzly population and roads can jeopardize that.

“It creates access for poachers and then generally shrinks habitat into smaller and smaller pockets. And those pockets end up getting too small and the bears have to get out of those pockets,” Bader said. “And when they do that, it really increases their risk of encountering a human or getting into the trash or something like that, leading to a conflict that results in the bear's death.”

According to Bader, the larger problem is not just individual bears, but also at the population level. If bears cannot move between these habitat areas, there are genetic consequences.

“Currently, all populations in the northern Rocky Mountains are isolated and none of them are large enough to be viable long-term. And the Bitterroot ecosystem has a large amount of suitable habitat for grizzly bears,” Bader noted. “And so it will be.” Establishing a population there would greatly increase the chances of grizzly bear survival throughout the northern Rocky Mountains.”

While the U.S. Forest Service tells MTN News that it does not comment on pending litigation, when it approved the change last September it outlined its plans to mitigate some of the problems that roads can cause for species. For grizzly bears, this means providing so-called “safe habitat,” or roadless areas.

Conservation groups fear this will lead to a patchwork of separate habitats.

“The problem is that the Forest Service measured 'safe habitat' for grizzly bears on tiny, one-acre patches of land. So you basically multiply my backyard by four and you have safe grizzly bear habitat. “And that’s just not how grizzly bear biology works,” Scrimshaw said.

Allowing bears to travel between safe habitats is key to ensuring populations can survive events like wildfires and drought.

“The whole connectivity thing, that’s the whole game for grizzly bears,” Bader noted.

The notice claims the change will not only impact grizzly bears, but will also harm bull trout. Sediment from roads can enter streams, clogging trout gills and clogging the steam itself, resulting in shallower, warmer water.

Earthjustice plans to move forward with the lawsuit unless the U.S. Forest Service changes its plans by mid-November.