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• Reference to Table 2.3-15 shows that shrub species Symphoricarpos oreophilus is <br />an important understory shrub in range sites A and B and is co -dominant with Ar- <br />temisia tridentata in range site C. The overstory shrubs with the highest den- <br />sity in range sites A and B are Quercus gambellii and Amelanchier alnifolia. The <br />stem density of Q. gambellii is 3.26 stems per square meter in range site B and <br />1.64 stems per square meter in range site A. Approximately twice as many Q. gam- <br />bellii stems per square meter are found on the west facing mountain shrub slopes. <br />The density of Amelanchier alnifolia in range site A and B is about equal. Table <br />2.3-9 indicates that the total mean stem density for range sites A and B are <br />approximately equal, i.e. 8.54 stems per square meter for range site A and 8.92 <br />stems per square meter for range site B. Two other shrubs which are to be con- <br />sidered subdominants in range sites A and B are Artemisia tridentata and Prunus <br />virginiana. <br />• 2.3.3.4 Diversit <br />Two different diversity indices were calculated for each range site. Generally, <br />only one diversity index was calculated for the entire range of lifeforms present <br />in a plant community. Since diversity index is calculated from some measured <br />parameter such as cover, production or density, a single index for an entire com- <br />munity requires that a common parameter be measured for all species or lifeforms <br />present. However, since the test for success of shrub reestablishment will be <br />based on density and the test for success of reestablishment of herbaceous spe- <br />cies will be based on production or cover, no one common parameter exists. <br />Therefore, it was decided to obtain an index for all herbaceous species based on <br />cover and an index for all shrubby species based on density. Such a method does <br />not favor either overstory or understory vegetation. Instead it provides a bet- <br />ter balance for establishing a diversified, stable post mine vegetative commun- <br />ity. <br />2-105 <br />In essence, <br />the diversity index <br />suggested by Bonham <br />(1980) is <br />really <br />a dominance <br />. <br />measure. It <br />does not take into <br />consideration how <br />individuals <br />of a <br />species are <br />2-105 <br />