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<br />history, and grazing history. At the Piceance Site, the overstory is generally open
<br />(50 to 80 percent cover), with understory species diversity and density inversely
<br />related to overstory closure (BLM 1994).
<br />The Sagebrush Association is usually an open stand of big sagebrush with an
<br />understory of grasses, including western wheatgrass, mutton bluegrass, cheat
<br />grass, needle-and-thread, Indian ricegrass, and various sedges (Tiedeman and
<br />Terwilliger 1978). Other herbaceous species adapted to xeric conditions that may
<br />occur at lower elevations include squirreltail, Colorado wildrye, goldenweed,
<br />and scarlet globemallow (BLM 1994). Common shrubs include Douglas
<br />rabbitbrush, flowery phlox, shadscale saltbush, gray horsebrush, and winterfat.
<br />Again, plains prickly pear is the only common forb (Tiedeman and Terwilliger
<br />1978).
<br />The Sagebrush Association dominates the relatively level, most-upland areas at the
<br />Piceance Site on Yamac loam soils. This community also occupies north-facing slopes of
<br />the upper reaches of most of the dry, ephemeral drainages to Piceance Creek, where it
<br />c,ccurs on Torriorthents-Rock outcrop complex soils, with fringed sagebrush, Indian
<br />ricegrass, and wheatgrass the dominant species (BLM 1982, Tiedeman and Terwilliger
<br />1978). The Sagebrush Association is used as winter range and cover for mule deer and
<br />elk (SCS 1982).
<br />The Sagebrush Association comprises 1,253 acres (31 percent) of the Piceance Site. Of
<br />these, approximately 45 acres would be disturbed and reclaimed for mining operations,
<br />and an additional approximately 31 acres would experience long-term disturbance for
<br />project facilities. Construction disturbance would affect approximately 20 acres of this
<br />vegetation type.
<br />Barren/Rock Outcrop Association -Barren lands are those areas such as barren rock,
<br />erosion pavements, rock outcrops, cliffs, and talus slopes that have little or no
<br />vegetation. The Barren/Rock Outcrop Association is characterized by a "bald"
<br />appearance due to the absence of trees and large shrubs. At the Piceance Site,
<br />these barren lands have 40 percent or more bare, exposed soil. What vegetation
<br />there is is dominated by grasses and cushion-type fortis. Important grasses
<br />include bluebunch wheatgrass, streambank wheatgrass, needle-and-thread,
<br />prairie junegrass, Indian ricegrass, and blue grama. Cushion-type fortis include
<br />buckwheat, daisy, phlox, globemallow, pussytoes, and nailwort, and associated
<br />low shrubs are fringed sage and rabbitbrush (BLM 1982). This community is of
<br />little benefit to wildlife; however, the rare, endemic plant species that exist in the
<br />vicinity of the project occur in the Barren/Rock Outcrop Association.
<br />At the Piceance Site, the Barren/Rock Outcrop Association dominates the south-facing
<br />slopes of the dry, ephemeral drainages to Piceance Creek, where it occurs on
<br />Torriorthents-Rock outcrop complex soils. The Barren/Rock Outcrop Association
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