Laserfiche WebLink
In 1999 reclamation, the total herbaceous cover ranged from 49.4 (Section 16) to 40.7 <br />• percent {West Pit) to 39.0 percent in the East Pit. Because of their youth (and the <br />inevitable prevalence of annual and biennial species), these areas would be subject to <br />reduction for excess annual/biennial growth. The resulting "allowable" cover ranges <br />from about 9 to 20 percent, far below the standard that, as discussed above, may be in <br />the range of 33 percent. Since such young areas would never be subject to <br />consideration for bond release, it does not matter that at this early stage they do not <br />meet the performance standards far mature vegetation. <br />r <br />Species Diversity <br />The standard for diversity of species in the Colowyo Mine.reclamation should be three <br />perennial cool season grass species and one perennial fort that offer from 3 to 50 <br />percent of the total vegetation cover. With this criterion in mind, all three 1997 <br />reclamation areas passed the standard. The growth of perennial plants in the 1999 <br />reclamation (i.e. areas only in their second growing season since germination) is not far <br />enough along, to be judged. None of the three 1999 reclamation areas yet has sufficient <br />development of perennials to pass the standard. <br />Looking at the bigger picture for species diversity, as reflected in species density data <br />(Figure 10), the levels observed in the Section 16 1997 reclamation at nearly 30 species <br />per 100 sq. m. are very much in the range and even in excess of native vegetation as <br />observed elsewhere in Northwest Colorado (see 1987 to 2000 Annual Monitoring <br />Reports of Seneca II and Seneca II-W Mines, Routt Co., CO). East Pit and West Pit <br />1997 levels of 20 to 21species per 100 sq.m. are probably indicative of the trend <br />downward that accompanies such strong dominance by introduced (and domesticated) <br />species such as smooth brome (Bromopsis inermisj, intermediate wheatgrass <br />(Thinopyrum intermedium), and crested wheatgrass (Agropyron cristatum, including <br />Siberian wheatgrass, Agropyron sibiricum). After five to six years, such stands <br />elsewhere in Northwest Colorado often exhibit species density values betweenl0 and 15 <br />species per 100 sq. m. or less. Species density values of young stands tend to be high <br />because of the prevalence of both native and introduced annual and biennial species. <br />Hence the values of 24 to nearly 30 species per 100 sq. m. in the three 1999 <br />reclamation areas. <br />L J <br />5 <br />