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UecFmber L'2003 Paae3-18 Townsend'S Big-eared Bat. Townsend's big-eared bats occur throughout western North America including much of Colorado, normally below 9,600 feet in elevation (Fitzgerald et al., 1994; Armstrong et al., 1984). Roosting colonies are in caves, mineshafts, and other man-made structures. The species forages over most habitat types except dense coniferous forests (Armstrong et al., 1984). Suitable roost and maternity sites are not present within the LBA tract area, and it is unlikely that this species occurs as a local resident. 3.6.2 Environmental Consequences Alternative 1 -Proposed Action The only surface disturbance that would occur in the LBA tract is surface subsidence, which could potentially affect wildlife habitat by minor surface cracking and by causing small, isolated changes in vegetation communities or surface topography. Gradual subsidence of six to eight feet is expected to occur on the ground surface overlying longwall mining areas. Surtace cracks up to 12 inches wide and 30 feet deep may occur in soil and rock. Cracks are more likely on ridgetops with bare rocks and cliffs, and less likely in valleys and other areas with deep soils. Soil cracks tend to fill with dirt and debris and heal relatively quickly. Cracks in bare rock are likely to remain longer. Cracks in cliff faces have a slight chance to disturb nesting or roosting wildlife such as peregrine falcons and bats. However, the cracks are likely to be minor, and would be additional to natural cracking and rockfall continuously occurring on the cliffs. Sensitive species such as peregrine falcons and bats occur rarely if at all on the cliffs in the LBA tract, and the chances of measurable disturbance to sensitive species by surface cracking are relatively minor. Little information is available about the potential effects of subsidence on plant communities. Subsidence monitoring by MCC on adjacent coal leases in the 1990s found no obvious changes to the plant communities as a result of subsidence within the region. Minor impacts to plants could occur along the edges of subsidence cracks and in limited areas where surface water flow is altered by surface cracking. However, these minor vegetation changes would be very small and would not be likely to measurably affect wildlife habitats or the continued existence of any federal listed or sensitive species. Subsidence could potentially accelerate mass wasting (landslides and rock falls). Natural mass wasting is locally common in the area particularly landslides and slumps associated with major precipitation events (Bureau of Land Management and Forest Service, 2000). These natural events are difficult to distinguish from possible subsidence-related effects, and many occur below the coal-bearing strata. Where the overburden is thick, such as in the proposed LBA tract, no increase in mass wasting can be considered likely based on available data. Underground mining has the potential to intercept ground water in faults. MCC estimates that about 150 acre-feet of water may be encountered underground in the LBA tract (Koontz, 2003). Also see Section 3.4.2, Environmental Consequences (Alternative 1 -Proposed Action). This encountered water would be considered non-tributary ground water, and it would not contribute to water depletion in the Colorado River Basin. Therefore, there would be no effects to the four Colorado River endangered fish species. Because the only surface disturbance resulting from the proposed project would be surface subsidence, individuals and habitats for elk, mule deer, Lewis's woodpecker, northern goshawk, hairy woodpecker, Envirnnr:ent,at >lssessmc!~i Mdest I=latiron LBA i i 8^t r~~_mrison Countv.:;olorado