Return of the lynx
December 30, 2005
SUMMIT COUNTY – Floating easily through the deep powder on its giant tufted paws, the lynx trots smoothly through the thick timber in Jones Gulch, hundreds of miles from where Colorado Division of Wildlife (CDOW) biologists released it last year. The cat stops for a moment and sniffs the air with a twitchy nose, perhaps catching the scent of a snowshoe hare in this drainage just east of Keystone. Then it moves on, headed north, bound for the dense spruce and fir forests of the Medicine Bow National Forest, where it may look for a den site and begin repopulating an area where lynx haven’t had a permanent presence in several decades.The magnificent native wild cats are back, thanks to a state re-introduction program that has seen the number of lynx in Colorado grow steadily during the past five years, due in part to continued releases, but also because the animals are breeding. The kittens are surviving and by all accounts thriving in Colorado’s mountains, which doesn’t surprise many of the wildlife biologists following the program, who say they knew all along that the state could provide good habitat for the carnivorous predators. Lynx have been located on all eight national forests in Colorado, according to state biologists, as they move northward from the release area in the San Juans.They’re back, and they are increasingly moving into the White River National Forest. So far, there hasn’t been any breeding documented, but the forest sits on an important crossroads between north and south, and could be a crucial link if the cats are to spread back into their historic range across all of Colorado’s mountains. So far, 43 lynx have been located in the White River National Forest, according to a CDOW report issued earlier this year.Those locations, based on satellite tracking data and aerial surveys, don’t mean that all those lynx are living permanently on the White River National Forest, but that they were pinpointed on the forest at some given moment in time. But the pattern of locations suggests that the forest is going to be an important area as the rare cats spread back across their native range. Important crossroads”Lynx use the entire area between Bakerville (east of the Eisenhower Tunnel) to Vail Pass to go from the southern part of the state to the north,” said CDOW’s Rick Kahn, coordinator the lynx program. “It is important if the state decides it wants lynx populations in the northern part of the state. What we’re doing with the Forest Service is looking at that whole area,” Kahn said, adding that I-70 and other development impacts in the region pose a formidable barrier for lynx trying to move north.The increasing number of lynx using the White River National Forest doesn’t surprise Keith Gietzentanner, the Glenwood Springs-based ecologist for the forest.”The majority of the forest is pretty good lynx habitat,” Gietzentanner said, explaining that the rugged mountains of the forest have plenty of the terrain favored by the cats – steep, high altitude north-facing slopes with plenty of downed timber for cover and forest patches of varied ages, where there is food and habitat for snowshoe hares, a mainstay of the lynx diet.”The majority of lynx locations is no surprise,” Gietzentanner said, suggesting that some lynx may even be setting up territories on or near the White River, especially south and east of Aspen and south of Vail in a triangular area roughly bounded by Vail, Tennessee Pass and Copper Mountain. That patch of forested mountains was described by Gietzentanner and other federal biologists as a “secondary core area” and “study area” for lynx, outside the immediate release zone in the San Juans, where many of the transplanted cats have settled.”There are some things we can do to help then, especially with regard to movement corridors,” Gietzentanner said.
According to Gietzentanner, it’s too early to tell for sure if Jones Gulch is one of those important movement corridors, although other state and federal biologists previously said that the gulch is a key link through heavily developed Summit County, where other avenues for north-south movement are blocked by Dillon Reservoir, exurban sprawl and busy highways.”We’ve had quite a few locations from that area, but they’re infrequent. It’s hard to say how important it is,” Gietzentanner said. Lynx have even been spotted at the ski area by snow groomers recently, Gietzentanner said, adding that some of those sightings were documented with pictures.Resort impacts?Ski area expansions and other related resort activities – including base area development – have long been at issue with regard to potential impacts to lynx habitat. The battle over Vail’s Category III expansion focused closely on the fact the planned new terrain would be smack-dab in the middle of the “last best lynx habitat” in Colorado, and more recent disputes over land-use allocations in the White River forest plan also revolved around lynx habitat.Jones Gulch is a prime example. Based on input from federal and state biologists, the Forest Service set aside the valley as a “forested movement corridor,” but Vail Resorts promptly appealed that designation, claiming that it could hinder existing and planned future ski area activities. Existing ski area uses have actually been “grandfathered in,” according to Gietzentanner, so there’s no need for the resorts to worry that lynx management measures may somehow restrict their current activities. The aim now is to ensure that the resorts are at least “permeable” to lynx movement. Nobody expects the cats to set up home ranges in the middle of a ski trail (although a few lynx previously settled quite close to the slopes at Telluride).”We have the capability for managing ski areas to have minimum habitat capability,” Gietzentanner said. “And ski areas only cover about 2 percent of the land in the White River National Forest. But the concern is always there because of their location, right in the middle of good lynx habitat,” he added.Gietzentanner said there are some proposals currently on the table (A-Basin’s Montezuma Bowl expansion, Jones Gulch snow cat skiing at Keystone) that will require careful evaluation, with a close look at topography and vegetation patterns.”The biggest issue for us is which habitats are the most important,” Gietzentanner said, explaining that ongoing monitoring from CDOW’s lynx program could help provide some management guidance during the next few years. More long-term, the most beneficial lynx measures might be to manage the forest so that there’s plenty of food for snowshoe hares, favored prey for the wild cats, Gietzentanner said. That means planning forest health and wildfire mitigation projects with one eye toward optimizing hare habitat, he added.Mapping lynx
The maps on CDOW’s web site showing lynx locations in the White River National Forest are interesting, but could also be slightly misleading, said Kurt Broderdorp, the Grand Junction-based biologist with the U.S. Fish and Wildlife Service who reviews many of the proposals for activities on federal lands in western Colorado for compliance with the Endangered Species Act.The dots may not reflect the true number of lynx on the forest, simply because state biologists don’t track the animals as frequently outside the core San Juan area. And some of the various dots could also represent sightings of one lynx at different times in different places, Broderdorp said.”There are more lynx out there than dots on the map,” he said.”There was a specific request for a map we could provide for a certain individual in the Department of Agriculture,” said Broderdorp, describing the history of the White River forest lynx map. Broderdorp was referring to Deputy Undersecretary David P. Tenny, who last spring ordered the White River forest to amend some of its lynx management rules after claiming there weren’t any lynx on the forest. Of course, the maps show clearly that the cats are using White River National Forest lands extensively.”We don’t know what the carrying capacity of the core area (in the San Juans) is,” said Broderdorp. “We do know that we have some kind of seasonal movement patterns. They’re cooped up all winter long. Then, in June, they’ll move 100 miles north of I-70. They want to get out and see the countryside.” Broderdorp said it was unclear initially how much good denning habitat there is in Colorado’s mountains. “They (biologists) were very conservative, saying, ‘you don’t mess with that type of habitat.’ They are looking for structure – downed logs. I’ve been into some den sites and it’s almost impossible to get a human body in there. We’re finding there’s a lot of denning habitat out there. There seems to be more available than we first thought. But we don’t really have any idea how many lynx the state of Colorado can support,” Broderdorp said.Number of individual lynx located on national forests in Colorado 1999-2004:Rio Grande NF (core release area) – 161San Juan NF – 144
Grand Mesa-Uncompahgre-Gunnison NF – 121Pike-San Isabel NF – 55White River NF – 43Arapahoe-Roosevelt NF – 28Routt NF – 10Medicine Bow NF 9Total lynx released since 1999 – 204Lynx kittens born in Colorado – 101CDOW biologist Tanya Shenk estimates that as many as 141 of the reintroduced lynx and 28 of the 55 kittens born in 2003 and 2004 could be living in Colorado. Researchers are monitoring 118 lynx with active radio collars and plans to replace some inactive collars during this winter trapping season, when they will also collar kittens born last spring. Another 15 lynx will be released this spring.