2018-04-02_PERMIT FILE - C1981019A (7)

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RULE 2 PERMITS threatened or endangered. Detailed descriptions of the six identified major vegetation community types and their sub -types, and qualitative descriptions of the minor communities/land use types are presented in Table 2.04.10-33. Major Vegetation Community Types Values for species diversity, production, and woody plant density are summarized by community type. Table 2.04.10-35 lists those species by community type found to represent from 3 percent to 50 percent relative cover (including second hits below the shrub layer). Table 2.04.10-36 displays vegetation production by community type, and Table 2.04.10-37 compares woody plant density of baseline and reference areas by community type. Table 2.04.10-38 shows the statistical comparison between baseline and reference areas by community type. Aspen - The aspen community within the Vegetation Study Area occupies 770 acres. It is found at higher elevations on steep slopes and throughout drainage bottoms that generally exhibit northeast to northwest aspects. Soils are typically well-developed. The aspen reference site is located adjacent to the southwestern corner of the Vegetation Study Area boundary and occupies 68.7 acres (Map 4C). This reference area represents the variety of site characteristics seen throughout the aspen community type in the Vegetation Study Area. It was also selected as a reference area because of its accessibility and the low probability of future disturbances. A total of 63 plant species were observed within the aspen community baseline study area while the reference area exhibited 41 taxa. No sensitive species were observed within this area. The noxious weeds Canada thistle (Cirsium arvense) and houndstongue (Cynoglossum ofcinale) were observed in the study area (Table 2.04.10-39). The average vegetation ground cover within the aspen community baseline study area was 75.45 percent with 0.0 percent rock, 19.97 percent litter, and 4.59 percent bare ground exposure. Dominant plant species and percent cover included: mountain brome (Bromus marginatus) with 13.86 percent, blue wildrye (Elymus glaucus) with 11.59 percent, bluegrass (Poa agassizensis) with 7.1 percent, mountain snowberry (Symphiocarpos oreophilus) with 6.72 percent, and nettleleaf giant hyssop (Agastache urticifolia) with 4.93 percent. Of the total plant cover, 96 percent (72.52 percent average cover) were perennial plants (excluding noxious weeds). Annual species contributed 4.0 percent and noxious weeds contributed 0.6 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 three of those species being grasses, two forbs, and two shrubs (Table 2.04.10-39). The average herbaceous production within the aspen community baseline study area was determined to be 1,249 pounds per acre, oven -dry weight, with 98 percent (1,226 pounds per acre) as perennials (grasses contributing 771 pounds per acre and forbs providing 455 pounds per acre), and 1 percent (12 pounds per acre) as annuals (all forbs). The remaining 1 percent (11 pounds per acre) was comprised of noxious weeds (Table 2.04.10-40). Woody plant density in the aspen community baseline study area was 4,685 woody plants per acre with dominance by mountain snowberry (2,858 plants per acre) and chokecherry (Prunus virginiana) (1,111 plants per acre). The shrub lifeform accounts for 93 percent (4,346 plants per acre), sub -trees account for 2 percent (96 plants per acre) and trees account for 5 percent (243 per acre) of the total (Table 2.04.10- 41). The density of larger aspen averaged 139 trees per acre using the point -center -quarter (PCQ) method (the difference between the two values was due to aspen recruitment — trees smaller than 5 feet that were not recorded in the PCQ measurements). The canopy cover in the aspen community baseline study area was Collom — Rule 2, Page 46 Revision Date: 12/30/16 Revision No.: TR -108