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26. It is not clear that the proposed reduction of the herbaceous cover and production standards <br />from 90% of reference area mean to 70% of reference area mean would be warranted for <br />sagebrush steppe revegetation areas, even given the seedmix adjustments and other practices <br />that will be implemented to favor woody plants. The Division will need to assess the <br />proposal in more detail before making a determination. As noted in the narrative, levels of <br />herbaceous cover on past reclaimed areas at Colowyo have exceeded the premine condition <br />by 30% to 50%. Given the episodic nature of sagebrush establishment observed in <br />northwest Colorado and documented in the literature for big sagebrush, compared to the <br />more consistent and reliable establishment of grasses, it may be reasonable to assume that an <br />herbaceous cover equivalent to 90% of the sagebrush reference area herbaceous cover <br />(30.17% cited) would become established within a relatively short time frame, particularly <br />given the allowance for interseeding of native grasses and fortis during the early years of the <br />liability period. <br />Herbaceous understory cover is important to provide quality habitat for sagegrouse and <br />other species, as well as to provide adequate soil protection. 70% of a reference area mean <br />of 30.17% would be 21 % herbaceous cover, which would seem to be quite a low cover <br />standard for the relatively low density mountain big sagebrush community that would be the <br />reclamation objective. <br />Please provide supporting data if available, to demonstrate that such a low herbaceous <br />cover standard is warranted to achieve the woody plant/big sagebrush densities that <br />will be required, and that the proposed herbaceous cover standard will be adequate to <br />control erosion. If such supporting data cannot be provided, the Division's <br />determination will likely be that 90% of the herbaceous cover (and production) of the <br />sagebrush reference area is an appropriate success criteria for the sagebrush steppe <br />reclamation areas. If data from future monitoring of sagebrush steppe reclaimed areas <br />indicate that adjustment of the criteria is warranted, a revision application with site <br />specific documentation can be submitted to request such modification. <br />27. The weighting percentages listed on amended page 4.15-13 for the Mountain Shrub, <br />Sagebrush, and Aspen Woodland Reference Areas, with respect to acreage weighted <br />comparisons applicable to the South Taylor expansion area, appear to be incorrect. <br />Specifically, the 25% factor for Mountain Shrub and 52% factor for Sagebrush appear to be <br />reversed; the mountain shrub community is the dominant vegetation type in the South <br />Taylor expansion area. Please revise the weighting factors as appropriate. <br />28. No rationale was provided for the proposed revision of the diversity success standard for the <br />pre-2008 grazingland reclaimed areas in amended Section 4.15.8. The current standard is: <br />• At least 4 principal species, with a minimum of 3 cool season grasses and 1 perennial <br />forb, each providing at least 3% relative cover, and; <br />• No single species provides in excess of 50% relative cover. <br />The proposed standard would be less stringent, and would require: <br />Colowyo Coal Company, C-1981-019 TR-72 <br />April 29, 2008 Page 13 <br />