2019-11-22_REVISION - C1981019 (2)

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RULE 4 PERFORMANCE STANDARDS sample can be obtained from the reference area, then a less complex one-sample t-test may be utilized. With the reverse null test, the smaller the variance (given by extra sampling) the better the chances of passing closely matched parameters. For certain statistical demonstrations of woody plant density,documentation of sampling adequacy is often problematic,hence Rule 4.15.11 (3)may be used in lieu of Rule 4.15.11 (2). Rule 4.15.11 (3) (a) is a reverse-null approach based on the median and requires a minimum of 30 samples. Rule 4.15.11 (3) (b) allows direct comparison with standards if a statistically adequate sample cannot be demonstrated in accordance with Rule 4.15.11 (2) (a), however, a minimum of 75 samples with a minimum quadrat size of 100 m2 is required (equivalent to total enumeration of 1.85 acres). Rule 4.15.11 (3) (c) is a standard-null approach based on determination of a"running mean" and a minimum of 40 samples is required. Success Evaluation To summarize, success evaluations involve either a direct or a statistical t-test comparison of appropriate parameters for each variable of interest (cover, production, diversity, or woody plant density). For monitoring efforts,comparisons shall be made directly with either the reference area parameters or the permitted standards to facilitate a determination of the progress of revegetation. In the case of ground cover and production,comparisons shall be made against reference area data of the same year. Diversity and woody plant density variables shall be compared against the standards defined above. For bond release efforts, direct comparisons are made when the revegetated area mean value for a given variable is greater than either 90% of the standard or the reference area mean assuming that a statistically adequate sample has been collected. If a statistically adequate sample cannot be obtained, a"reverse-null"hypothesis test may be employed as detailed in C.R.S. Rule 4.15.11 (2) (c). If an adequate sample is obtained for a particular variable, but the mean is less than 90% of the reference area mean or standard, a "standard-null" hypothesis t-test may be employed as detailed in C.R.S. Rule 4.15.11 (2) (b). For the typically problematic variable of woody plant density, Colorado has implemented three alternate adequacy/success evaluation methods under C.R.S.Rule 4.15.11 (3)that may be utilized in lieu of those detailed under 4.15.11 (2). Until experience dictates which procedure is best (because these are relatively new metrics to the science), it would be prudent to collect a minimum of 75 belt transects (at least 100 m2 in size) as indicated in 4.15.11 (3)(b)(i). These data can then be used for the various analyses/comparisons. r Rule 4 Performance Standards 4-81 Revision Date: 11/18/19 Revision No.: MR-211