By Lynn Burton
Sopris Sun Staff Writer
Bighorn sheep no doubt hate fire, but they will sure warm up to its aftermath following a Upper Colorado River Interagency Fire and Aviation Management Unit controlled burn up Avalanche Creek south of Carbondale on April 7.
Early this week, White River National Forest wildlife biologist Natasha Goedert explained how the controlled fires help bighorn sheep.
“This area is winter range,” Goedert told The Sopris Sun.
In the Avalanche Creek burn area (about two miles east of Highway 133) steep, rocky hillsides hem in the valley floor to the north, with spruce-covered hillsides to the south.
The one-day burn, the third in the past three years with more planned for future years, covered 90 acres of grass and brush such as Gambel oak and serviceberry. The burn was originally slated to cover 500 acres over 3-5 days but was called off after the April 7 burn due to various conditions.
During a local press tour for the burn on April 7, White River National Forest fuels specialist Jim Genung said the Avalanche Creek area has “lost” two burn-cycles, with each covering 50-75 years, due to fire suppression after the Crystal River Valley was first settled in the 1880s.
As a result, Gambel oak, serviceberry and other vegetation have clogged up the valley floor. At the same time, piñion-pine and juniper have worked their way down to the valley floor from hillsides to the north. This makes it more difficult for bighorn sheep and other wildlife to make their way through the valley floor, and also makes them expend precious energy during the winter.
Thick stands of brush also make it harder for bighorns to spot predators such as mountain lions and sometimes even golden eagles.
“They (bighorns) use their eyes to see predators,” Goedert explained. “They feel safer in open habitat. … Sometimes they use steep cliffs and other terrain to avoid them (predators) … So, we like to keep the habitat open.” In the winter, with deep snow, it’s even harder for bighorn to escape.
Prescription burns also create more forage the year following the operation, as burned brush sends up new chutes with more leaves.
“It puts weight on them (the sheep),” Goedert continued. “So they come into spring in better condition. …Winter range is a small subset for them, but it’s most important.”
The Avalanche Creek bighorn herd, which often grazes in the open land across from Penny Hot Springs in the winter, can probably use all the help it can.
Goedert said the herd has been on the decline a bit since the 1990s, when it numbered close to 150 head. In the past few years, the herd declined to about 60-75 but has stabilized at that number.
“They’ve been holding steady since the decline,” she said.
Colorado Parks and Wildlife puts GPS collars on some of the sheep to track them and try to diagnose the reasons for the decline.
“This is one of Colorado’s more important herds,” Goedert said.
Bighorns migrate to the Avalanche Creek area starting in late November and stay there through March and into April. They start to move higher, after the snow melts, in May, the same month females typically give birth.
As for the ongoing Avalanche Creek prescribed burn program, it’s part of the Aspen-Sopris Wildlife Habitat Improvement Project, which calls for fire and mechanical treatments across approximately 45,600 acres of forest, shrubland and grassland in the Aspen-Sopris Ranger District and small portions of the Eagle and Rifle ranger districts.
One part of the wildlife improvement project says, “Observations of pinion-juniper, mountain shrub, aspen and subalpine grassland vegetation … indicate that this vegetation has reduced forage values for bighorn sheep, elk and mule deer, and a decrease in vegetation composition that benefits a variety of songbirds, small mammals, and native fire-adapted plants. Without improvement of habitat in key areas, populations are expected to decline beyond desirable levels.”
At the Avalanche Creek prescription burn tour last week, Genung said the White River National Forest has used prescription burns since 1977.
Published in The Sopris Sun on April 13, 2017