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and the undisturbed area for the variables of ground cover and production. For the <br />variables of woody plant density and species diversity, Colowyo shall compare <br />revegetated area parameters against defined standards detailed later in this section. Data <br />to be used in these comparisons must be from statistically adequate sampling (where <br />necessary) as indicated in Rule 4.15.11. In instances where grazingland targeted <br />reclamation areas exhibit the characteristics of the sagebrush steppe areas and can meet <br />the release standards for core or ecotonal sagebrush steppe, Colowyo will seek release <br />and credit for the creation of those areas towards fulfillment of the minimum habitat <br />development requirement post-2008 (450 acres). In the unlikely but not impossible event <br />that areas targeted for sagebrush steppe display community characteristics that will not <br />meet the sagebrush steepe area release criteria but do for the grazingland criteria, <br />Colowyo will designate those acres as grazingland. Colowyo will have to specifically <br />designate the location of both grazingland and sagebrush steppe areas prior to the <br />initiation of phase III bond release data collection. For descriptive purposes, "evolved" <br />sagebrush steppe areas refer to lands originally seeded to grazingland that exhibit <br />sufficient community characteristics of the sagebrush steppe community to be fully <br />released as either core or ecotonal areas. Areas defined as "targeted" sagebrush steppe <br />are by definition the areas originally seeded to the sagebrush steppe plant community that <br />exhibit the characteristics of that community and meet either the core or ecotonal <br />requirement for full release. <br />Herbaceous Cover <br />For both Pre-2008 and Post-2008 revegetation targeting (and achieving) the rangeland <br />land use subcomponent of grazingland, herbaceous cover of the revegetated area will be <br />considered adequate for final bond release if it is not less than 90% of the herbaceous <br />cover as determined from the reference areas with a 90% statistical confidence utilizing a <br />standard students statistical t-test comparison of the means. As allowed under the rules <br />promulgated on 9/14/05, these comparisons may utilize one of three methods detailed <br />under Rule 4.15.11 (2) [(a), (b) or (c)]. Also as allowed by Rule 4.15.7 (4), either <br />weighted-average or individual protocols will be followed depending on the resulting <br />community that evolves (see Section 4.15.7 above). For grassland testing the weighted <br />average approach (Rule 4.15.7 (4) (b)) will be utilized where reference area data and <br />revegetated area data are "weighted" (each combined into single values for comparison) <br />based on the proportional acreage of pre-mine communities within the disturbance area <br />footprint. Testing will then follow procedures detailed under Rule 4.15.11 (2) with <br />preference being given first to subsection (a) [direct comparison], second to subsection <br />(c) [reverse-null testing], and third subsection (b) [classic t-test]. <br />For "targeted" Post-2008 sagebrush steppe revegetation (targeting the rangeland land use <br />subcomponent of wildlife habitat), herbaceous cover will be considered adequate for final <br />bond release if it is not less than 70%* of the sagebrush reference area's herbaceous cover <br />• The value of 70% has been selected given the following rationale: 1) herbaceous competition must be <br />significantly restricted to facilitate emergence and growth of shrubs as indicated under Rule 4.15.11 (3) (ii); <br />2) the original value is 90%; 3) a value of 50% seems too low to adequately control erosion; 4) by regulation <br />(4.15.11 (3)(a)) a reduction to 70% is allowed for one of the demonstrations for revegetation success for <br />4.15-17 Revision Date: 12/22/09 <br />Revision No.: TR-84