2010-12-17_REVISION - C1981019 (160)

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alluvial deposits along the numerous drainages within the study area, or the concave basins of the drainage headwaters. The wetland and riparian bottom subtypes are restricted to this physiographic location, whereas the sagebrush, mountain shrub, and grassland types have "invaded" from surrounding uplands to take advantage of the more mesic conditions. The Bottomland community generally exhibits deep to very deep soils with somewhat elevated moisture levels that result from side-slope out-wash, varying amounts of lateral subirrigation from stream flow, flood flows, and from occasional seeps and springs. The uplands only receive meteoric water. Because of this additional moisture availability, vegetation within the bottomland community grows with elevated density and productivity in comparison to the adjacent uplands. The Aspen communities are located on high elevation, steep slopes and drainages that generally exhibit northeast to northwest aspects, and on well-developed soils. The final major community is Grassland. This predominately early-seral community is most often found in the flat or gently sloping uplands where natural and prescribed burns have removed the overstory sagebrush or mountain shrub vegetation and the usually sub-dominant grasses and forbs have flourished. Occasional small patches of the grassland community can be found along high elevation ridges where thin soils and high winds inhibit shrub densities. Similarly, small patches of natural grasslands persist where soil conditions are such as to naturally discourage shrub growth. Four minor communities/land uses are found in study area: Disturbed Areas, Cultivated Land, 41 Improved Pasture, and Wetland. Disturbed Areas include relatively permanent man-made disturbances that exhibit little to no vegetation, and include areas such as major roads as well as ranch buildings, yards, and stockpens (drill pads and similar areas were excluded from this designation due to their small size and temporary nature). Small roads (e.g., "two-tracks" and single lane paths) were typically not designated under this category due to their "narrow" character. An additional "disturbed" area located outside the vegetation study boundary, but within the wildlife study boundary, includes the present pits, waste rock dumps, facilities, and revegetated areas of the Colowyo Mine. The Cultivated Land designation is found in the northeastern corner of the study area where dryland crop farming is undertaken on a 2-year rotation (one-year fallow, one-year with crop). Wheat is the typical crop grown in these small fields. A single field of Improved Pasture that has not reverted back to a natural community is located in the southeastern portion of the study area where a relatively flat bench of higher elevation shrubland / forest has been cleared and planted to predominantly smooth brome (Bromus inermis) in the recent past. The final minor community that occurs as a subtype of the Bottomland type, is wetland. This minor community will be addressed at length in this document owing to its inordinate importance as a floristic assemblage and wildlife habitat. (However, this community was not formally sampled in the same manner as the major communities, but rather in a form typically utilized for U.S. Army Corps of Engineers permitting, which will take primacy over State permitting.) C1EE]IDAIP3 CMMK AM(CII T35, INC. Page 3 2005 Collom Vegetation Survey