In the Colorado Rockies, a herd of elk, known as unit 45, has been tracked by biologists for years. In the past decade, their numbers have fallen dramatically, with the cause pointing to an increase in outdoor recreation activities in their territory, reported The Guardian.
Biologists counted more than 1,000 elk in the mountains surrounding Vail, Colorado, just several years ago. New counts taken in February of this year have brought that number down to around 50.
The researchers performing the annual elk count left notes about their findings, or lack thereof.
“Very few elk, not even many tracks. Lots of backcountry skiing tracks.”
Bill Alldredge, a now-retired wildlife professor at Colorado State University, began studying unit 45 in the 1980s in response to an increase in ski resorts and trails. The professor conducted an experiment by placing radio collars on various members of the herd to study the impact of human disturbances on the health and survival of elk calves.
The experiment consisted of sending eight hikers out into calving areas until the elk showed signs of being bothered by the disturbance, either by standing up or walking away. The results of the study were shocking, revealing that around 30 percent of calves died when their mothers were disturbed more than seven times during calving. If the mother was disturbed more than 10 times, all their calves would die.
Interestingly, when the disturbances stopped, the population of calves bounced back, revealing the true impact of human activity on elk survival. The researchers were unable to discover the reason as to why calves died after the disturbances, but believe that it may have to do with the mother getting spooked by human activity and running too far away for the calf to catch up or because the stress of the disturbance caused them to produce less milk.
Outdoor recreation has been increasing in Colorado at exponential rates over the past decades. Trail use specifically near Vail has more than doubled since 2009, while night trail use in many areas has gone up by at least 30 percent in the same amount of time. Due to improved technology and a desire to escape crowds, people are venturing out increasingly more into previously untouched area of the wilderness.
Other explanations for the rise in outdoor recreation activities in the Colorado mountains include a mixture of visitation campaigns and an increase in social media exposure, which has turned national parks and wilderness areas into top tourist destinations.
Colorado Parks and Wildlife’s district wildlife manager Devin Duval predicts the worst if trail-building and human activity continue to expand into the territory of the local fauna.
“It will be a biological desert,” Duval says.