After several recent events that brought outdoor mountain bikers too close to nature for their own good, some have come forward to warn about the dangers of biking in the great outdoors. Dr. Christopher Servheen is one of those people. Servheen, who served on a committee that investigated a mountain biker death after the man collided with a grizzly bear near Glacier National Park, is a retired coordinator for the grizzly bear recovery program of the U.S. Fish and Wildlife Service. He recently spoken out against “recreational sports in the areas where grizzlies live,” the New York Times reports.

“We tell people not to run in grizzly bear habitat, to make noise and to be aware of their surroundings,” said Servheen. “Agencies are permitting the very activities we are telling people not to do.”

For example, this past summer, Servheen attempted to stop two ultramarathons in the Flathead National Forest because of the times at which both were scheduled. The one held last weekend occurred during “a time when bears are particularly active in foraging for food” in preparation for hibernation, according to the New York Times. But those actively engaging in mountain biking and other outdoor recreation interested in exploring backcountry for their sport seem to be unaware of the dangers or encroachment that this activity has on the wildlife that live in these remote areas. And the increased interest in exploring the public land in the West by bike or hike is resulting in increased conflicts between wildlife and humans—and, particularly, with grizzly bears that may feel threatened or scared.

“Bears respond to surprises usually by fleeing, but sometimes by attacking whatever it is that is surprising them,” said Dr. Stephen Herrero, a professor emeritus of ecology at the University of Calgary and author of Bear Attacks: Their Causes and Avoidance. “Events like runners and bike riders and anything else that suddenly thrusts a disturbance or surprise into their environment, they sometimes respond by attacking.”

“I try to avoid mountain biking in any area that is grizzly bear habitat,” Herrero continued. “There are plenty of areas that aren’t.”

And, while the current focus is on how mountain biking may disturb grizzly bears, according to the New York Times, other experts think that the activity may also impact elk, deer and other animals and “disrupt their lives.” In fact, studies have been conducted that show outdoor recreation—not just mountain biking—can have dire consequences on wildlife.

“Overall we found a moderate to strong effect of recreation on wildlife across the board,” said Courtney Larson, who published a literature review of 274 studies in 2016 for her Ph.D. at Colorado State University and has just completed a meta-analysis on the effects of recreation.

“It’s a little difficult to tease out on its own because most of the time, mountain bikes use occurs on multiple-use trails with hiking, mountain biking, dogs and horseback riders on the same trails,” said Larson.

According to the New York Times, a 2018 study discovered that elk move when people do—and they tend to move more from bikers than hikers. In fact, in recent studies, researchers found that “when a mountain bike appeared, elk fled 1,500 meters” and fled even further—2,000 meters—when trying to flee from an all-terrain vehicle. This need to relocate as soon as people start to pressure them can disrupt feeding habits and create long-term problems for the entire herd.

“If a female doesn’t put on enough body fat, she might not be able to conceive the next year,” said Michael Wisdom, a researcher with the Pacific Northwest Research Station, part of the Forest Service, and an author of the study. “An increase in time running reduces time foraging.”

However, even with these studies and information, will it prevent people from taking to the woods for outdoor recreation? Nope. This means other solutions need to be identified to keep wildlife safe from unnecessary disturbances and people safe from dangerous encounters. These solutions include “better management of trails used by mountain bikes, as well as restricting use on some trails, lowering any speed limits and permitting bike riders only on dirt roads,” according to the New York Times.

“Careful planning of the trail corridor and the design” is also a good idea, said David Wiens, executive director of the International Mountain Bicycling Association in Gunnison, Colo. “That’s where the agencies get involved and the wildlife specialists, who can come up with the proper location of the trail based on their expertise. In certain cases, there are seasonal closures for wildlife.”