Laserfiche WebLink
Vegetative litter (prior years growth, dead wood, and other biologic organic material) <br />comprised 17.33 percent ground cover within the RPE area. Bare soil was not <br />• encountered in the cover sampling. Rock accounted for 0.67 percent of cover <br />encountered in the RPE area. <br />Herbaceous Production <br />Results of herbaceous production sampling in the oakbrush vegetation community are <br />presented in Table 3. Mean total herbaceous production of the sampled quadrats on the <br />RPE area was 17.4 g/m2 (155.1 Ib/ac). Herbaceous production quadrat weights were <br />highly variable, with the standard deviation being 65 percent of the value of the <br />herbaceous production mean. When plotted, the herbaceous production values illustrated <br />a non-normal distribution which was bi-modal in nature. It may be hypothesized that low <br />and variable levels of herbaceous production within the oakbrush community can be <br />attributed to the density of the shrub and tree canopy, which effectively limits sunlight to <br />the low growing herbaceous species. Field observation noted that areas of greater <br />herbaceous production were correlated with openings in the canopy. <br />Woody Plant Density <br />As with vegetation cover, Quercus gambelii accounted for the majority of woody plants <br />encountered. Quercus gambelii provided 123.3 stems/]00 square meters (4988.4 <br />stems/acre). Symphoricarpos rotundifolius was the second most dense woody species <br />• with 72.6 stems/100 square meters (2938.0 stems/acre). Four remaining woody species <br />accounted for the remaining density as follows; Amelanchier alnifolia with 7.8 stems/100 <br />square meters (315.7 stems/acre), Prumrs virginiana with 5.7 stems/100 square meters <br />(229.3 stemslacre), Rosa woodsii with 3.3 stems/100 square meters (132.2 stems/acre), <br />and Juniperus osteosperma with 0.6 stems/100 square meters and 24.3 stems/acre. <br />Species Diversity <br />Within the 1995 RPE area sampling three lifeforms were represented; graminoids, forbs, <br />and woody arborescent species. The lifeforms included four species of perennial grasses, <br />one annual grass, five perennial forbs, and seven woody shrubs. Of the 17 species <br />encountered during cover sampling on the RPE area, 15 were native (three grasses, five <br />forbs, and seven woody shrubs) and two were introduced (two grasses). As would be <br />expected in a largely undisturbed old age shrub dominated community, introduced species <br />accounted for only 2.13 percent of the mean vegetation cover on the RPE area in the 1995 <br />sampling. The single introduced annual accounted for 0.13 percent mean cover and 0.10 <br />percent relative cover. Seasonality of RPE area species was predominantly cool season, <br />with one perennial forb being identified as warm season. Woody species were <br />predominantly deciduous, with two species being evergreen. Table 1 provides a listing <br />and characterization of the plant species encountered during cover sampling at the RPE <br />area. <br />• <br />-7- <br />