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ERO Resources <br />overgrazing also fawned the wildrye, which is tolerant of shallow soils. <br />• Colorado wildrye prevails where soils are shallow also as a result of the <br />bunchgrass habit. The dense clumps of this wildryv trap moving soil <br />particles and form small soil islands at their bases and between clumps. <br />In this way an adequate subatrats with a fair nutrient regime is assured <br />for the spread of the perennial clumps. <br />Colorado wildrye has increased at the e~grenw of western wheatgrass and <br />other rhizomatous grasses. This has ocourred because the habitat fawning <br />the rhizomatous species has bwn eliminated by overgrazing and erosion. <br />Remnants occur, however. These relict areas occur on sites where soils <br />are shallow and fins in texture and in sagebrush sites where sheep use is <br />low as a result of the lack of access by road. Even the remnant sites <br />have been affected by sheep grazing. On the shallow soils where fine <br />textures prohibit the increase of cheatgrass where the perennial pressures <br />from sheep grazing are too high for this species, annual Forb communities <br />or patches of Gordon saltbush occur. Both species are tolerant of the <br />heavy clay soils and high erosion rates. Evidence of erosion on these <br />• 61te6 can be seen from the pedestaling that has occurred around the few <br />sagebrush that occur there and from the numerous local run-off channels. <br />Colorado wildrye does not occur on these areas as a result of the <br />moderately deep soils and the fine textures. Sagebrush has been largely <br />eliminated due to trampling. This factor is in abundant evidence. The <br />heavy soil textures also do not favor the sage. <br />A general circumstance that relates directly to the intensity of sheep use <br />within the sagebrush-wheatgrass typo corresponds to e~osure and proximity <br />to roads. Those areas within the type that occur on or Haar south- or <br />southwest-facing slopes display greater degrees of evidence of sheep use <br />lMcDaniel and Tiedeman 1981). These sites are also invariably Haar roads <br />used to access sheep during winter to feed hay. This effect impinges on <br />all of the categories and inclusions that make up the type, although <br />e~osed knolls are affected to the greatest extent. <br />• <br />II.F-38 <br />