2012-08-10_PERMIT FILE - C1981018A

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FRO Resources d. BIG SAGEBri1.SFi TYPE • (1) Location and Distribution: Vegetation dominated by big sagebrush occur as inclusions in other sagebrush-dominated types. The big sagebrush stands occur primarily on north-facing slopes. Soils underlying the dense big sagebrush inclusions are deeper than surrounding soils. Cover values for sagebrush are correspondingly higher on these sites than on adjacent sites. These soils are also more coarse in texture and support patches of rabbitbrush within the sagebrush. f2) Structure and C,o~mnosition; The surface of the Big Sagebrush Inclusions is relatively freB of herbaceous growth under the dense shrub canopy and is marked by pedestalling due to sheet wash and rill erosion. • The herbaceous layer in the dense sagebrush is poorly developed, Cheatgrass is the most common species. Other species that occur in this inclusion type are western wheatgrass and stickseed. The dense shrub canopy intercepts significant amounts of moisture and light. Although the canopy also traps snow, light remains limiting to herbaceous growth. The deep, coarse to loamy soils allow rapid infiltration of moisture, Cheatgrass appears to compete well under these ernironmental circumstances as a result of an extensive fibrous root system and its ability to utilize a sufficient amount of the soil moisture as it passes through the upper soil horizons (Hulbert 1955, 1967 and Evans et al. 1970). The shrub layer is dominated by big sagebrush. Few other shrub species were encountered during sanpling. Other relatively common species includes shadscale, spiny hopsage and rabbitbrush. Gordon saltbuFh occurs in places in this inclusion where the "A" horizon has been truncated by erosion. The e~osed weathered shales provide a favorable habitat for the saltbush, just as sandy pockets fever big rabbitbrush. The predominance • II.F-32