2013-04-10_PERMIT FILE - C1981019A (4)

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RULE 2 PERMITS The average cover within the grassland community baseline study area was 58.19 percent, with 1.37 percent rock, 25.83 percent litter, and 14.62 percent bare ground exposure. Dominant plant species and their ground cover percentage included: western wheatgrass (15.23 percent), cheatgrass (12.33 percent), Sandberg bluegrass (6.4 percent), Japanese brome (5.92 percent), and prairie pepperweed (Lepidium densiorum) (2.5 percent). Of the total plant cover, 60 percent (34.8 percent average cover) was due to perennial plants (excluding noxious weeds). Annual species contributed 39.6 percent and noxious weeds contributed 0.6 percent of the composition. Four 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 all four of those species being grasses (Table 2.04.10 -51). The average herbaceous production within the grassland community baseline study area was determined to be 1,008 pounds per acre, oven -dry weight, with 74 percent (742 pounds per acre) due to perennials (grasses contributed 670 pounds per acre and forbs contributed 54 pounds per acre) and 25 percent (252 pound per acre) due to annuals (grasses contributed 197 pounds per acre and forbs contributed 56 pounds per acre). The remaining 1.4 percent (14 pounds per acre) was due to noxious weeds (Table 2.04.10 -52). Woody plant density in the grassland community baseline study area was 974 woody plants per acre with dominance by holly grape (Mahonia repens) (345 plants per acre), low rabbitbrush (Chrysothamnus viscidiorus) (209 plants per acre), mountain snowberry (186 plants per acre), and mountain big sagebrush (Artemisia tridentata ssp. vaseyana) (184 plants per acre). The shrub lifeform accounted for 100 percent of the total (Table 2.04.10 -53). The grassland community type in the study area has been divided into two relatively arbitrary sub -types based on whether or not the area was subject to a recent prescribed burn (Sagebrush Reduction area), or is naturally lacking a shrub component or was naturally burned in the past (Grassland). The sagebrush reduction areas are generally located on the relatively flat upland areas surrounded by over - mature stands of mountain sagebrush and just north of the transition zone between mountain shrub and sagebrush zones. Most of the older sagebrush reduction areas now contain enough reinvading sagebrush to be classified as sagebrush, but the more recent areas exhibit only a few plants and therefore, can still be classified as grassland. The naturally occurring grasslands are scattered throughout the study area in small patches. Some of these patches are located along high - elevation, wind -swept ridgelines and summits where thin soils favor grass and forb development over shrubs. Annual bromes have invaded some of the past natural burn areas (especially at lower elevations) and have slowed the re- invasion of sagebrush into these areas. In the grassland reference area, average ground cover was 51.85 percent with 0.0 percent rock, 30.45 percent litter, and 17.7 percent bare ground exposure. Dominant plant species and their ground cover percentage included: western wheatgrass (19.35 percent), prairie pepperweed (13.3 percent), Sandberg bluegrass (7.55 percent), and cheatgrass (5.35 percent). Of the total plant cover, 64 percent (33.0 percent average cover) was due to perennial plants (excluding noxious weeds). Annual species contributed 36 percent and noxious weeds contributed 0.0 percent of the composition. Four 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, one forb, and one shrub (Table 2.04.10 -51). The average herbaceous production within the grassland reference area was 876 pounds per acre, oven dry weight, with 87 percent (758 pounds per acre) due to perennials (grasses contributing 743 pounds per acre, forbs contributing 13 pounds per acre, and sub - shrubs contributing 2.5 pounds per acre) and 13 percent (118 pounds per acre) due to annuals (grasses contributing 6 pounds per acre and forbs contributing 112 pounds per acre). Noxious weeds were not found in my of the sampling quadrants in this reference area (Table 2.04.10 -54). Collom — Rule 2, Page 65 Revision Date: 9/28/11 Revision No.: PR -03