GENERAL48585 - Laserfiche WebLink

Home Browse Search

• e. Species Diversity t9ined Land Reclamation prescribed success criteria for species diversity, as folloxs: "The operator" Coors Energy Company "shall establish a minimum of seven (~} perennial species, of which four (4) are warm season grasses, two (2) are cool season grasses, and one (1) is a forb, to be measured using relative frequency (taken by species}. No one component (species} of the above should comprise greater than 400 relative importance, nor less than ~ relative importance. Sandsage is to be reestablished as the woody plant species to the woody plant density standard.. This standard is" These standards are "subject to periodic reevaluation and adjustment as warranted by site-specific data provided by the operator to the Division." From letter of Michael S, Savage to Bill Robie, June 25, 1982. Coors accepts these success criteria because they are subject to adjustment. The success criteria were derived from frequency data of Table 2.04.10(4), which shows that four warm-season grass species, two cool-season grass species, and one forb species had relative importances (RI} of 2 to 39~. The sub-totals of RI's were 54.2, z6.6, and 17.50 for warm-season grasses, cool-season grasses and forbs, respectively. These sub-totals might be important in adjusting success criteria. On test plots, Cools established five warm-season grass species, one cool- season grass species, and zero forb species at RI between Z and 400 (Table 2.04.10(5)}. Since seeding test plots, Coors has revised the seed mixture to improve species diversity. Additional revisions likely will be tried in an attempt to achieve the success standards prescribed by MLR. Nevertheless, Coors is especially concerned about the prospects for keeping any single forb species in the stands at RI greater than 3/, unless the highly undesirable western ragweed volunteers prolifically. Alfalfa and cicer milkvetch are expected to fade out because of low phosphorous concentrations in the sandy soil. As on test plots, a great many forbs may volunteer, but no single species other than western ragweed has RI greater than one percent in pre-mined vegetation. At present, the prospects of achieving the forb standard appears to be most uncertain and questionable. To evaluate species diversity among herbaceous perennial species, the frequencies of individual species will be determined by listing all species found rooted in 250 placements, located in IO transects of 25 placements each, of a 12-inch quadrat. Sampling precision is, thus, given in a table of "confidence limits of a binomial," which may be found in most statistical textbooks. Because this is also the method proposed for monitoring seeding success, Coors will detect problems at any early time.