1999-04-26_PERMIT FILE - M1999051 (2)

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i • J-2 SAGEBRUSH ASSOCIATION Vegetation in the Sagebrush Association is influenced by many interacting and independent ecological factors including climate, soils, topography, fire history, and grazing history. The overstory varies from open to completely closed with understory species diversity and density inversely related to overstory closure (BLM, 1994). The subspecies Wyoming sagebrush is 2 to 3 feet tall and occupies Yamac loam soils on ridges; the subspecies basin big sagebrush is typically 6 to 8 feet tall, sometimes has closed overstory, and occurs in valley bottoms. The Sagebrush Association is usually an open stand of sagebrush with an understory of grasses including western wheatgrass, mutton bluegrass, cheatgrass, needle-and-thread, grass, Indian ricegrass, and various sedges (Tiedman and Terwilliger, 1978). Common shrubs include Douglas rabbitbrush, flowery phlox, shadscale saltbush, gray horsebrush and winterfat. The Sagebrush Association is used as winter range and cover for deer and elk. It is also used by cattle and horses. The Sagebrush Association covers approximately 619.4 acres or 46.9 percent of the Lease area. Approximately 35.7 acres are planned to be disturbed by the facilities. J-3 BARREN/ROCK OUTCROP ASSOCIATION Barren lands are those areas such as barren rock, rock outcrops, cliffs, and talus slopes of the dry or ephemeral drainages which feed into Yellow Creek. The soil mapping unit is the Torriorthents- Rock outcrop complex. These lands have little vegetation but are used by deer during severe winters due to their south facing exposures and limited snow cover. The vegetation of this association includes grasses: bluebunch wheatgrass, streambank wheatgrass, needle-and-thread grass, junegrass, indian ricegrass, and blue grama; forbs: buckwheat, daisy, phlox, blobemallow, pussytoes, and nailwort; and shrubs: fringed sage and rabbitbrush (BLM, 1982 and 1999). The Barren/Rock Outcrop Association covers approximately 5.1 percent of the Lease area. Only a small amount of this association is planned to be disturbed by the facilities. J-4 RANGE SITE DESCRIPTIONS Range site descriptions developed by the Natural Resources Conservation Service (NRCS; formerly the Soil Conservation Service) also have been applied to the project area including the Lease area, and are used by the BLM and NRCS. The descriptions are shown on Figure J-2 for the Rock School Lease. They are described in the Range Site Descriptions at the end of this discussion. G:\LM\M78545.002\Reclamation\Reclamexh.DOC J-3