Laserfiche WebLink
The sagebrush community had the most arid aspect of all vegetation under <br />study. Characteristic species which were regularly present included green <br />needlegrass (Stipa viridula), western wheatgrass (Agropyron smithii), <br />milkvetch (Astragalus miser), arrowleaf balsamroot (Balsamorhiza <br />sagittata), junegrass (Koeleria cristata) and Wyoming paintbrush (Castilleja <br />lineariaefolia) . <br />Diversity of fortis and grasses was fairly high in this vegetation type. The <br />open aspect of the shrub canopy allowed for many herbaceous species to <br />become established. <br />On the mine plan area, sampling occurred in relatively widely separated <br />locations, because of the extent of the sagebrush type (Figure 1). At- <br />tempts were made to distribute samples more or less evenly among suitable <br />locations. The reference area was chosen adjacent to the southeast edge <br />of the proposed pit limit. Not all portions of the reference area were <br />suitable for sampling, as some areas supported no sagebrush. These azeas <br />_ were not sampled. <br />3.4.1 Herbaceous Biomass <br />Fourteen plots were clipped on the mine azea and ten were clipped on the <br />reference area. The mean dry weight biomass was estimated at 84.8 + 30.8 <br />g/m= on the mine area and 104.8 t 19.6 g/mz on the reference azea <br />(Tables S.1 and 5.2). Both areas were sampled sufficiently to meet the <br />statistical requirements. Since the mean biomass on the reference area was <br />higher than on the mine area, no statistical comparison was necessary. <br />However, the means were not significantly different at the 95$ confidence <br />level using atwo-tailed t test. <br />Species which were most abundant in the clipping plots included green <br />needlegrass, bluegrass, foothills brome, silvery lupine (Lupinus <br />argenteus), arrowleaf balsamroot, and nettleleaf giant hyssop. More <br />species chazacteristic of mesic sites were found on the reference azea than <br />on the mine area. This was reflected in the higher biomass occurring on <br />the reference area. <br />• <br />