Laserfiche WebLink
RULE 4 PERFORMANCE STANDARDS <br />sample can be obtained from the reference area, then a less complex one -sample t-test may be <br />utilized. With the reverse null test, the smaller the variance (given by extra sampling) the better <br />the chances of passing closely matched parameters. <br />For certain statistical demonstrations of woody plant density, documentation of sampling adequacy <br />is often problematic, hence Rule 4.15.11 (3) may be used in lieu of Rule 4.15.11 (2). Rule 4.15.11 <br />(3) (a) is a reverse -null approach based on the median and requires a minimum of 30 samples. <br />Rule 4.15.11 (3) (b) allows direct comparison with standards if a statistically adequate sample <br />cannot be demonstrated in accordance with Rule 4.15.11 (2) (a), however, a minimum of 75 <br />samples with a minimum quadrat size of 100 m2 is required (equivalent to total enumeration of <br />1.85 acres). Rule 4.15.11 (3) (c) is a standard -null approach based on determination of a "running <br />mean" and a minimum of 40 samples is required. <br />Success Evaluation <br />To summarize, success evaluations involve either a direct or a statistical t-test comparison of <br />appropriate parameters for each variable of interest (cover, production, diversity, or woody plant <br />density). For monitoring efforts, comparisons shall be made directly with either the reference area <br />parameters or the permitted standards to facilitate a determination of the progress of revegetation. <br />In the case of ground cover and production, comparisons shall be made against reference area data <br />of the same year. Diversity and woody plant density variables shall be compared against the <br />standards defined above. <br />For bond release efforts, direct comparisons are made when the revegetated area mean value for a <br />given variable is greater than either 90% of the standard or the reference area mean assuming that <br />a statistically adequate sample has been collected. If a statistically adequate sample cannot be <br />obtained, a "reverse -null" hypothesis test may be employed as detailed in C.R.S. Rule 4.15.11 (2) <br />(c). If an adequate sample is obtained for a particular variable, but the mean is less than 90% of <br />the reference area mean or standard, a "standard -null" hypothesis t-test may be employed as <br />detailed in C.R.S. Rule 4.15.11 (2) (b). <br />For the typically problematic variable of woody plant density, Colorado has implemented three <br />alternate adequacy / success evaluation methods under C.R.S. Rule 4.15.11 (3) that may be utilized <br />in lieu of those detailed under 4.15.11 (2). Until experience dictates which procedure is best <br />(because these are relatively new metrics to the science), it would be prudent to collect a minimum <br />of 75 belt transects (at least 100 m2 in size) as indicated in 4.15.11 (3)(b)(i). These data can then <br />be used for the various analyses / comparisons. <br />Rule 4 Performance Standards 4-80 Revision Date: 11/27/18 <br />Revision No.: TR -129 <br />