Seasonal Closures Matter More Than Ever

Column by Ted Benge

Though it has come too soon, springtime in the Rockies is a euphoric awakening. We revel in the long, sunny afternoons, enjoy slush skiing up high and hike on dry earth closer to the valley floor. As we shed our puffy jackets and head for the hills after the dark and cold winter months, we may be tempted to skirt winter closures and ride and hike our favorite summer trails. But even in this year’s unusually hot and dry climate, it is especially important to respect wildlife.For some of our valley’s most cherished residents, spring is a critical season, when they are especially vulnerable to the impacts of human disturbance. 

Elk are a prime example; spring finds females in the final terms of their pregnancies, relying on their reserves to deliver their young and lactate. Males, who had entered winter weakened by the frenzy of their fall rut, subsist on marginal feed on lonely slopes above larger herds of cows. 

Females produce their calves in late May or early June, following an average gestation period of 250 days. The miracle of new life happens in seclusion as cows slip away from the herd, which attracts predators, to drop and nurture their spindly newborns alone. Calves are born nearly scentless and with mottled camouflage coats; they avoid predation by nestling, motionless, in ground cover.

Unfortunately, multiple studies show human recreational activity to have severe short- and long-term effects on these and other ungulates. Elk  display flight responses to ATV and mountain-bike use at over 1,000 yards, and at around 750 to 500 yards to hiking and horseback-riding disturbances. They will avoid regularly used trails by a buffer of approximately 1,000 feet, which effectively eliminates much usable habitat. In fact, a Theodore Roosevelt Conservation Project analysis showed that over 40 percent of Colorado’s most important elk habitat is affected by trail use. 

Curtis Tesch, Colorado Parks and Wildlife District Wildlife Manager for the Upper Roaring Fork, says trail use pushes elk into less favorable havens, with lower-quality forage and more susceptibility to predation. This displacement in the upper Roaring Fork is forcing elk to use oak-brush covered hillsides over traditional aspen and long-grass ecosystems.

Though our impact on elk and deer may not be evident - calves do not usually drop dead as we hike past - the long-term effects can be severe, says Tesch. Animals may show an immediate flight response when they detect humans, but even if they don’t bolt they still experience a fear response and disruption to normal feeding patterns. The caloric toll impacts pregnant or lactating females. “Down the road, that animal could abort or abandon their young,” Tesch says. Quantitative data from a large body of research supports these claims, and shows that human disturbance directly diminishes reproductive productivity.

In the Roaring Fork Valley, the Avalanche Creek elk herd (DAU-15) has seen calf:cow recruitment ratios nosedive since the 1980s. While formerly it was approximately 60:100, today the ratio stands around 30-35 calves to 100 cows, indicating a declining herd. CPW is undertaking a long-term study to further explore causality, and the drivers are complex and interrelated, but recreation and winter/springtime disturbances are emerging as leading causes of calf mortality. Complete study results have not yet been published.

Local critical winter habitat includes: the Crown, Light Hill, Williams Hill, Thompson Creek, the Lorax Trail, the Sutey Ranch zone and the Government Trail area by Snowmass Village. In aggregate, winter range is scarce and is a limiting factor; especially because there is strong overlap with prime real-estate development areas.

Winter closures are not promulgated out of spite, they are a necessity. Many of the valley’s most popular summer recreation destinations intersect the most important winter range. 

While some ungulate herds in the West migrate hundreds of miles between their summer and winter range, elk in the Roaring Fork Valley traditionally migrate locally. They descend from high-elevation summer range to south-facing hillsides just off the valley floor, where they subsist on grass and woody browse. With such a narrow movement band, maintaining access corridors is crucial, and groups like Roaring Fork Safe Passages are driving efforts to build road-crossing infrastructure to expand total available habitat.

Closure dates vary by elevation, but are extremely important; it may feel hot in town and lower trail segments may be dry, but elk and deer have no escape while the high country remains snowed in. 

Tesch says: 

“Despite clear signage, gates and cameras, area closures are often violated.”

 More times than I care to count, I have personally discovered tracks left by hikers, XC skiers and mountain bikers, often with dogs, blowing past closure signs.

The easiest way to reduce impact is to abide by seasonal closures. I have found myself caught up in springtime fervor, too, concocting mental justifications to push “just a little further,” but it is not fair to wildlife.  Even with restrictions, we are blessed with access to ample trails and recreational outlets that have less impact on wildlife. 

As always, but in spring more than ever, leash dogs, use quiet voices, and turn back if you encounter wildlife herds. The baby animals will thank you.