Laserfiche WebLink
Range site C, based on 1980 data, has a herbaceous plant density (H') of .8992, <br />and a shrubby plant density (H') of .4131 (Tables 2.3-20 and 2.3-21). <br />Six plant species comprise 71% of the total herbaceous plant density. Agropyron <br />trachycaulum and Comandra umbellata each provide 6.31% of the total diversity <br />(H'). Either species may be included in the species list to provide 71% of the <br />total diversity. The shrubby fraction of range site C has only two species pro- <br />viding 71% of the total diversity index (H')(Table 2.3-21). <br />The above tables on diversity include perennials, biennials and annuals. Poison- <br />ous plants and undesirable biennials and annuals were not utilized in calculating <br />diversity since in a revegetation plan, undesirable plant species will not be <br />utilized. <br />• 2.3.4 Condition and Trend <br />A <br />A description of the actual condition and trend of rangelands should always be <br />prefaced by a description of past land use and management practices. A complete <br />and historic description of past land use is provided in Section 2.5. <br />All range sites within the proposed mine plan area have traditionally been used <br />for livestock grazing, primarily sheep, under diverse ownerships. Small herds of <br />cattle have used the area, but the predominance of dense shrub has restricted <br />such use. Domestic sheep grazing has been controlled by herders, with fences <br />established primarily to denote property boundaries. Water sites consist of <br />small stock ponds within the various drainages. <br />A determination of trend is not practical at this time. Trend analysis requires <br />a minimum of five years of data to provide any degree of reliability. Therefore, <br />an estimate of trend on pre -mine areas will be developed later. <br />2-112 <br />