Laserfiche WebLink
Five species of the seventeen encountered during cover sampling accounted for greater <br />than three percent relative cover. Four of the five species were woody plants. These <br />species included; Quercus gambelii with 77.91 percent relative cover, Symphoricarpos <br />ro[undifolius with 7.17 percent relative cover, Amelanchier alnijolia with 3.97 percent <br />relative cover, Juniperus osteosperma providing 3.78 percent relative cover, and Poa <br />prate~uis with 3.10 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 community or azea. Total vegetation cover on <br />the RPE area was very consistent. Minimum sample size for the total cover parameter <br />was calculated at one (1) after fifteen samples had been taken. <br />Total herbaceous production was significantly more variable at the RPE area. Based on <br />the information from fifty quadrats, a minimum sample size of 2l3 was calculated. It is <br />not uncommon for production to be significantly more variable than vegetation cover, for <br />the reason that cover values range from zero-100 percent while production values may <br />range from zero-infinity. As noted above, a plot of the herbaceous production data <br />yielded a distribution which was bi-modal. Since the species contributing to herbaceous <br />production occur in the lowest stratum of the community, it may be hypothesized that <br />herbaceous production may be directly related to upper canopy density, though this <br />hypothesis would require significant additional data to be proved or disproved. <br />• Woody plant density data were more consistent than those of herbaceous production. <br />Based on the fifteen belt transects sampled, a minimum sample size of seventeen was <br />calculated, yielding a confidence level of approximately 87 percent. <br />COMPARISON OF OAKBRUSH SAMPLING AT THE WEST ELK MINE <br />In 1982 oakbrush communities at the West Elk Mine were quantitatively sampled. One <br />oakbrush community was to remain undisturbed as a reference area. The other oakbrush <br />area would be disturbed during mine facilities construction. The parameters of vegetation <br />cover, herbaceous production, and woody plant density were evaluated with the following <br />results. <br />Oakbrush Location Mean Cover (%) Herb. Production <br />m2 Woody Density <br />#/100mz <br />1982 Affected 46.24 55.7 784.0 <br />1982 Reference 58.64 53.6 533.4 <br />1995 RPE area 82.00 17.4 213.2 <br />I '~ <br />U <br />-8- <br />