2008-05-28_REVISION - C1981019 - Laserfiche WebLink

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herbaceous cover, which would seem to be quite a low cover standard for the relatively low density mountain big sagebrush community that would be the reclamation objective. Please provide supporting data if available, to demonstrate that such a low herbaceous cover standard is warranted to achieve the woody plant/big sagebrush densities that will be required, and that the proposed herbaceous cover standard will be adequate to control erosion. If such supporting data cannot be provided, the Division's determination will likely be that 90% of the herbaceous cover (and production) of the sagebrush reference area is an appropriate success criteria for the sagebrush steppe reclamation areas. If data from future monitoring of sagebrush steppe reclaimed areas indicate that adjustment of the criteria is warranted, a revision application with site specific documentation can be submitted to request such modification. Colowvo's Response: There is no supporting data directly on point to support the position proposed because this circumstance has never been proposed before. Furthermore, the state's opinion that this "seems to be quite a low cover standard" is similarly based on no data. In fact, the original value (90010) was no better supported at the time it was originally proposed in the mid 1970's. Regardless, the state's concern is warranted and has been strongly considered by Colowyo prior to proposing a reduction from 90% to 70%. However, four critical concepts or schools of thought are missing from the state's response. First and foremost, the reduced cover (and production) standard is only for sagebrush steppe vegetated communities, which will be located in areas that are restricted to 10% slope or flatter and therefore, at minimal exposure to erosion. Second, for those areas where the shrub take from initial seeding is only fair, there will be little opportunity for new plant establishment if the herbaceous community becomes too dense too quickly. If the grass population is not restricted throughout a sufficient period of time (perhaps as much as 10-15 years), there will be few micro-niches available for the episodic recruitment to the shrub population. If Colowyo is forced to raise the ground cover of grasses too quickly, the "ecotonal " areas that are conducive to increased shrub populations will be lost, thereby reducing opportunities for an increase in shrub density. This phenomenon has been observed at the CSU test plots where shrub recruitment continues on the more barren plots, but has ceased on the dense herbaceous plots. To the contrary, for those circumstances where an excellent shrub take occurs at the time of initial seeding, supplemental grass and forb interseeding may be necessary to achieve even a 70% value. It has been observed on multiple occasions for hard rock mine reclamation that an excellent shrub take can somewhat suppress the herbaceous population in much the same manner as occurs on overgrazed native range that exhibits disclimactic levels of sagebrush. If Colowyo were able to obtain such success with shrub density, it should not then be penalized for that success with a 90% cover and production criterion. Third, the state has placed emphasis on the initial ground cover values obtained for the sagebrush reference area (30.17%). However, this value is not frozen in time. In 2007, the herbaceous cover value was 42.25% that would translate to a 70% success criterion of nearly 30% absolute ground cover. In comparison to the 1982 value of 30.17%, any reclamation achieving this value would have returned 100% of the 1982 reference area value. Although, the opposite could also occur, the point is that the soil conditions on gently sloping ground should be adequate with 70% of the herbaceous cover to preclude excessive erosion. Furthermore, given the propensity of nature to fill voids, it is very unlikely that any deficiencies in this regard will be maintained for very long.