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Biological Assessment for DMG Permit Renewals McClane Canyon & Munger Canyon Mines have been found in rocky outcrops of south or east-facing slopes (Hill 1943). Midget-faded rattlers prey opportunistically on a variety of small vertebrates. Long-term persecution and extermination of this venomous viper out of concern for the safety of people and their domestic livestock or pets is thought to have greatly reduced populations across the west (Hammerson 1999). Impacts to midget-faded rattlesnake in the assessment area are probably limited to habitat bisection by roads and accidental road kill, although disturbance of hibernacula may be possible from subsidence events. Given the limited areas of pre-existing surface disturbance and level of operational activities at the mine sites, the proposed actions are not likely to cause measurable effects on or jeopardize the continued existence of the midget-faded rattlesnake. 5.5 Mammals Canada Iynx (T) is the only federally-listed mammal potentially affected by the proposed actions. The lynx was listed in 2000 at Federal Register 65(58):16051-16086. Historic populations of lynx have likely been extirpated from Colorado since the early 1970s. Lynx historically occurred in Colorado in low numbers above 9,000 feet in the Park, Gore, San Juan, and La Plata mountain ranges, and in appropriate habitat on the White River Plateau (Fitzgerald et al. 1994). Re-introductions of lynx in the state have met with some success, with CDOW reporting about 47 percent survivorship and moderate to high reproductivity (23 possible mating pairs) of the 204 animals released since 1999 (Shenk 2006). Factors affecting lynx survival, reproduction, and successful dispersal include certain aspects of timber management; motorized and developed recreation; trails, roads, and highways; livestock grazing where understory vegetation or aspen clone regeneration is inhibited; minerals extraction operations; illegal shooting and trapping; and depredation (Ruediger et al. 2000). No lynx habitat or primary prey base (snowshoe hare) habitat is present in or adjacent to the assessment areas. Primary habitat is spruce /fir /mixed conifer / lodgepole pine forests; secondary habitat is mixed deciduous /conifer forests (Fitzgerald et al. 1994; Ruediger et al. 2000). Designated critical habitat for lynx is currently being proposed at Federal Register 70(216):68294-68328 by the USFWS in portions of Maine, Minnesota, Montana, Idaho, and Washington. Although no designated critical habitat for lynx is being proposed in Colorado, the Lynx Conservation Assessment Strategy (Ruediger et al. 2000) provides for "lynx analysis units" (LAUs), which receive management considerations similar to designated critical habitat. The proposed actions addressed in this BA do no! take place within any mapped LAU in Colorado. Five bat species, described in the following paragraphs, potentially occur in the assessment areas. Activities in McClane assessment area potentially affecting roosting bats would be occasional vibrations from subsidence, and possibly noise and vibrations from traffic in McClane Canyon around the area of permitted surface disturbance. Activities at McClane and Munger potentially affecting foraging bats would be evening, night, and early morning mine traffic traveling across the East Salt Creek riparian corridor, and to a lesser extent, traffic traveling through the areas of permitted surface disturbance. Mine haul trucks and other vehicles traveling on Highway 139 throughout the East Salt Creek riparian corridor could also potentially affect foraging patterns of bats. The effects of subsidence vibrations and traffic on bat populations have not been studied. Whether suitable maternity roosts or winter hibernacula habitat exists for large colonies of any bat species within the assessment areas is unknown, but doubtful given the geology of the area. Impacts from traffic or subsidence would likely affect solitary individuals or exceedingly small colonies of any bat species present, but are not likely to jeopardize the continued existence of any bat species. Big free-tailed bat (S). Only five scattered documented occurrences of big free-tailed bat-none in Garfield County-have been recorded in Colorado, the northern limits of the species' range March 27, 2006 13 Rare Earth Science, LLC