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• 4.0 DISCUSSION <br />It was necessary to establish four vegetation reference areas to adequately <br />sample the types of plant communities present at the Hayden Gulch Mine. <br />Combining any of these communities for sampling would not have produced <br />satisfactory results. Adding a fifth community type was not necessary <br />since any transitional areas could be encompassed within one of the four <br />types. Though the existing vegetation map (3R Corporation, 1977, and <br />Figure 1) shows a serviceberry-sagebrush vegetation type, it was suf- <br />ficiently similar to either the chokecherry or sagebrush types that it did <br />not require sampling on its own. Serviceberrys were present in this type <br />but usually at low density and never at such a high density as to signifi- <br />cantly affect distribution or abundance of other vegetation components. <br />The data tables for each community type are the best documentation of <br />species abundance, and distribution of vegetation on the mine property <br />and in the reference areas. Table 25 summarizes the means from these <br />• tables and lists the minimum number of samples required to estimate within <br />10$ of the populations actual mean value with 80$ statistical confidence. <br />In all cases, the actual number of samples taken (n) was equal to or <br />greater than nmin, the number required to meet the statistical require- <br />ment. <br />By listing all the means together, similarities and differences can be seen <br />between the community types. Herbaceous biomass did not vary greatly <br />between the cmunitiee, the range of mean values was from 53.4 to 104.8 <br />g/m=. The sagebrush community had the most variable biomass at 84.8 <br />and 104.8 g/m= on the mine and reference areas, respectively. <br />The Gambel oak areas had lowest biomass overall at 57.7 g/m2 average <br />between the mine and reference areas. The chokecherry areas had higher <br />average biomass at 75.7 g/m=. The aspen areas had somewhat higher <br />average biomass at 86.4 g/m=. <br />Herbaceous cover was more variable between the sampled communities than <br />• was biomass. Due to its occurrence on more arid south and west-facing <br />exposures, the sagebrush type had lowest cover at only 31.0$ and 34.0$ <br />on the mine and reference areas, respectively. The aspen and Gambel oak <br />