Biologists increasingly confident about lynx recovery in Colorado |

Biologists increasingly confident about lynx recovery in Colorado

In 1999, soon after Canada lynx were released into San Juan Mountains, wildlife biologists were shocked to discover that four lynx had quickly starved to death.Public criticism was withering. Colorado’s lynx recovery effort looked to many people like one giant miscalculation and the architects of the reintroduction like heartless scientists run amok.But now, after three straight years of ever-larger numbers of kittens, 101 altogether, wildlife biologists are reporting realizations of their highest hopes. The reproduction shows that there is both sufficient habitat and food for the lynx. They are getting a toehold in the state where they have largely been absent for 30 years.”Getting kittens was a milestone,” says Tanya Shenk, lead lynx researcher for the Colorado Division of Wildlife. “Getting kittens to survive through the first winter was a milestone. Now, we’re looking for another milestone when those kittens have kittens of their own.”Researchers have been able to document only one additional lynx dying of starvation. A greater problem have been highways and humans with guns, resulting in 63 documented deaths.”I think it’s fulfilling our highest expectations,” said Rich Reading, the director of conservation biology at the Denver Zoo and a member of the advisory panel for the lynx reintroduction. “We’re not done yet, but it’s definitely a feel-good story,” he added.The total population of lynx, including surviving kittens, is now estimated at 169. That includes the 46 kittens found this year in the central and southern mountains of Colorado, all located south of Interstate 70. Researchers suspect more kittens were born.’Tolerably common’Lynx were among the many species of wildlife in Colorado that gradually disappeared during the 20th century. In a survey published in 1911, Merritt Cary of the U.S. Biological Survey reported lynx remained “tolerably common” in many mountain regions of the state. Yet, by the 1960s, owing primarily to trapping and other efforts to exterminate coyotes and other predators considered a problem to livestock producers, lynx had become scarce.The last confirmed lynx in Colorado were at Vail. A trapper killed one, but said he saw a second one as well. However, paw prints of what was believed to be native lynx have been noted from time to time since then.The potential presence of lynx in Blue Sky Basin made the animals a point of contention when Vail Mountain expanded in the 1990s. During the same time, environmental activists petitioned for listing the lynx for protection under the Endangered Species Act in 16 states outside of Alaska where they once existed. That effort finally succeeded in 2000.Seeing that the species would likely be listed, state wildlife officials began lobbying for a reintroduction, and a key discussion took place on a rafting trip down the Dolores River, in southwestern Colorado, during the summer of 1997. Various top biologists told John Mummu, then director of the agency, why they thought the effort would succeed.Their argument partly was one of hard reality. Given the likelihood of federal listing, federal land managers would be required to protect habitat on federal lands just in case lynx returned or still existed. Better to have lynx and see what they need to survive, went the argument, than have to guess. There was even some hope that a successful program could allow the lynx to be delisted in Colorado, thus giving state authorities, instead of the federal government, control of the wildlife steering wheel. The ski industry, which funded a portion of the initial reintroduction, agreed.Stumbled at the startIn planning the reintroduction, biologists studied what was known about lynx in Canada and Alaska and made some assumptions about their habitat needs in Colorado. Nearly the only guess that came up short was when and how to release the lynx.The first lynx were held briefly and then released in mid-winter, a major miscalculation. Taken aback by the starvations, the wildlife biologists fattened up the lynx on rabbits before releasing them in spring. The procedure revised, the lynx survived.Other educated guesses were correct. For example, they said lynx would primarily stick to the elevation band of 9,000 to 11,500 feet, where both snow cover and the spruce-fir forests are most plentiful in Colorado. They have.Also as predicted, lynx have largely stuck to forested areas. And finally, it took about three years for the lynx to begin reproducing.The greatest unknown has to do with their diets. Research indicates that, at least during winter, the lynx diet consists overwhelmingly of snowshoe hare, just as in Canada and Alaska. But in those places, snowshoe hare population wax and wane in 10-year cycles, and populations of lynx similarly wax and wane a few steps behind.Nobody knows whether snowshoe hare populations behave similarly in Colorado, says Shenk. In other words, while the lynx reintroduced so far seem to be doing fine, the story could change if the population of snowshoe hare plummet.Fewer population crashesGary Patton, a wildlife biologist who formerly worked for the U.S. Fish and Wildlife Service, say the habitat is different in Colorado than in Alaska, with important repercussions. The habitat is more patchy here, which means that hare populations won’t increase as much, and hence there will be fewer lynx. But he also says hare populations won’t decline as precipitously.”You won’t get the cycling,” he says. “You will have a lower overall population over a far larger area, but on the other hand, it will be a more stable population.”Yet another question has to do with snow compaction. One theory is that snowmobile tracks in particular, but even cross-country ski and snowshoe tracks, could give competing species an advantage. The tracks compact the snow, providing solid footing for coyotes and bobcats, which have smaller paws. This could make them more competitive with lynx in chasing snowshoe. A lynx’s key advantage is its oversized paws, which allow it to more easily stay afloat in powder snow. This is the theory used in decided what people can do in the forests, but it’s too soon to test that hypothesis in Colorado because there are just too few lynx on the ground, Shenk says. She says an experimental research project that might have a detrimental effect on lynx would interfere with the current goal of bringing back the species.Compatibility of lynx and ski areas is another problem that’s far from being resolved. Lynx and ski areas both favor the same areas, which in Colorado is almost exclusively Forest Service land. Because ski runs are often cut in forests of spruce-fir trees, there is inherent conflict, says Rocky Smith of Colorado Wildlife, an environmental that focuses on public lands. “It’s an open question whether ski areas in their collective effect on lynx will be,” Smith says. “Maybe it’s not enough to be bad, I don’t know.”Says the Denver Zoo’s Reading, “To a certain extent, lynx and ski areas can co-exist. But, it’s like anything: It’s how you manage the ski area and the ski expansion.”

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