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Species Composition . <br />Within the 1995 NGWRA sampling, four lifeforms were represented; graminoids, forbs, <br />succulents, and woody shrubs. The lifefonns included four species of pererutial grasses, <br />two species of annual grass, two annual forbs, one succulent, and six woody shrubs. Of <br />the fifteen species encountered during cover sampling on the new reference azea, native <br />species predominated in number over introduced species, twelve to three. 7'wo grasses <br />and one forb were introduced. The seasonality of the community was divided bE:tween <br />warm and cool reason, with graminoids ew:nly split and the forbs cool season. The shrubs <br />were all deciduous, but tend toward late season anthesis and seed set. Table 't pro~rides a <br />fisting and characterization of the plant species encountered during cover sampling at the <br />NG WRA. <br />Four species accounted for greater than three percent relative cover. These species <br />included Bromus tectorum with 52.63 percent relative cover, Sarcobatus vermi,:ulatus <br />with 20.45 percent relative cover, Hilaria jamesii with 10.12 percent relative cover, and <br />Gutierrezia sarothrae with 5.67 percent relative cover. <br />Sample Adequacy <br />Calculation of the minimum sample size: for a given parameter provides a basis for <br />estimating variability within a vegetation a~mmunity or revegetated area. Total vegetation . <br />cover on the NGWRA was very consistent. Minimum sample size for the total vegetation <br />cover parameter was calculated at three (3) after fifteen samples had been taken. Total <br />herbaceous production was more variable, and a total of fifty samples were collected. The <br />minimum sample size calculated for herbaceous production was 65. Woody plant density <br />was very variable within the NGWRA, partly attributable to the variable quantities of <br />Gutierezzia sarothrae and Chrysothamnus viscidijlorus. A minimum sample size of 121 <br />was calculated based on fifty samples. Tables 2-4 present the sample population <br />parameter values. <br />IV. DISCUSSION AND CONCLUSIONS <br />COMPARISON OF GREASEWOOD 12EFERENCE AREAS <br />The original greasewood reference area was originally selected in 1983 as an area that <br />would be used to compare revegetated areas at the mine for revegetation success. This <br />area was selected to be representative of the greasewood shrubland vegetation community <br />within the mine permit area. Sampling of the original greasewood reference area was <br />undertaken in 1983 by Western Resource Development Company, and the results <br />presented here originate from that sampling which is contained in the Powderhorn Coal • <br />Company CDMG permit document. Recently, both Powderhorn Coal Company and the <br />-6- <br />