2010-12-17_REVISION - C1981019 (106)

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RULE 2 PERMITS perennials (grasses contributing 562 pounds per acre and forbs contributing 258 pounds per acre) and 11 percent (105 pounds per acre) due to annuals (grasses contributing 86 pounds per acre and forbs contributing 19 pounds per acre). The remaining 0.3 percent (2.6 pounds per acre) was due to noxious weeds (Table 2.04.10 -62). Woody plant density was 8,758 plants per acre with dominance by mountain snowberry (5,083 plants per acre), Gambel oak (1,351 plants per acre), chokecherry (694 plants per acre), serviceberry (Amelanchier alnifolia) (530 plants per acre), and mountain big sagebrush (519 plants per acre). The shrub lifeform accounts for 83 percent (7,305 plants per acre) and sub -trees account for 17 percent (1,453 plants per acre) of the total (Table 2.04.10 -63). In the mountain shrub reference area, average cover was 62.75 percent, with 0.5 percent rock, 26.3 percent litter, and 10.5 percent bare ground exposure. Dominant plant species and their ground cover percentage included: mountain snowberry (15.8 percent), mountain big sagebrush (12.5 percent), bluegrass (6.6 percent), cheatgrass (5.2 percent), and tailcup lupine (Lupinus caudatus) (3.0 percent). Of the total plant cover, 88 percent (55.1 percent average cover) was due to perennial plants (excluding noxious weeds). Annual species contributed 12 percent and noxious weeds contributed 0.0 percent of the composition. Seven perennial species contributed at least 3 percent relative cover or composition (3 percent is the typical lower limit for plant diversity bond release evaluations), with two of those species being grasses, two forbs, and three shrubs (Table 2.04.10 -61). The average herbaceous production within the mountain shrub reference area was 804 pounds per acre, oven -dry weight, with 82 percent (663 pounds per acre) due to perennials (grasses contributing 588 pounds per acre and forbs contributing 75 pounds per acre) and 18 percent (141 pounds per acre) due to annuals (grasses contributing 131 pounds per acre and forbs contributing 10 pounds per acre). Noxious weeds were not found in any of the sampling quadrants in this community (Table 2.04.10 -64). Woody plant density in the mountain shrub reference area was 19,376 woody plants per acre with dominance by mountain snowberry (11,101 plants per acre), mountain big sagebrush (3,097 plants per acre), Gambel oak (3,144 plants per acre), and serviceberry (1,433 plants per acre). The shrub lifeform accounts for 84 percent (16,279 plants per acre) and sub -trees account for 16 percent (3,097 plants per acre) of the total (Table 2.04.10 -65). The comparison of the calculated t- statistic (t *) for the mountain shrub community baseline study area and the mountain shrub reference area with the respective tabular t values indicates that in each case t* is less than t. So, it can be concluded that the total vegetation ground cover and production for the mountain shrub community baseline study area is comparable (equal) to the values obtained from the mountain shrub reference area (Table 2.04.10 -38). Sagebrush — The sagebrush community baseline study area vegetation occupies 5,699.6 acres. It occurs at lower elevations occupying the relatively flat uplands or benches (mesic sub -type) and steeper southeast - facing slopes (xeric sub - type). The sagebrush reference area site occupies 30.9 acres (Map 4C). A total of 93 plant species were observed within the sagebrush community baseline study area, while the reference area exhibited 35 taxa. No sensitive species or noxious weeds were observed within the sagebrush community baseline area or the sagebrush reference area (Table 2.04.10 -34). The average ground cover within the sagebrush community baseline area was 55.24 percent, with 2.5 40 percent rock, 25.5 percent litter, and 16.8 percent bare ground. Dominant plant species and their ground cover percentage included: mountain big sagebrush (17.0 percent), western wheatgrass (4.4 percent), Japanese brome (3.6 percent), and Sandberg bluegrass (3.3 percent). Of the total plant cover, 88 percent Collom — Rule 2, Page 67 Revision Date: 1/23/09 Revision No.: PR -03