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habitats on the study area. The mixed brush transect (PG -2) revealed greater levels of <br />ase than either the forb/sagebrush (PG -1) or aspen (PG -3) transects. Little difference in <br />level of use was detected between the forb/sagebrush and aspen transects. The aspen <br />transect was not established as early as the others due to later retention of snow cover. <br />This may have had a minor influence on the data for the first examination period. <br />The elk and deer which winter on the study area were observed on the southerly exposures <br />or wind-blown ridges where snow does not accumulate to the great depths that are found on <br />northern exposures. Results of the browse utilization measurements recorded in May of <br />1974 substantiate this observation (Table 11-8). Transect B-1, located on a southerly <br />exposure, had the highest level of usage of the three sites. Levels of past usage (values <br />A and B) reveal that this area had received heavier usage during previous winters as well. <br />The 51.8 percent utilization of the current annual growth (value C), although high, is not <br />considered excessive. Sustained use of 80 percent or more would be considered harmful to <br />this species (Shepherd, 1971). <br />Transects B-2 and B-3 revealed low utilization for the winter of 1973-74. The shrubs on <br />these transects had some evidence of browsing in previous winters but not nearly to the • <br />degree observed on Transect B-1. These two transects were covered by deep snow <br />throughout the winter season. Opportunistic observations on the study area also revealed <br />generally heavier browsing of scattered shrubs on the southern exposures and light <br />browsing of shrubs on north -facing slopes. Mountain mahogany, a very palatable shrub <br />occurring on southern exposures, showed evidence of browsing on two- and three-year old <br />wood in some instances. <br />Measurements of summer browse utilization conducted during September of 1974 revealed <br />minor amounts of browse use (Table 11-8). Big game animals consumed more forbs and grass <br />during the summer than during the winter, and consequently did not require large amounts <br />of browse in a summer diet. Forage was most abundant in the summer and grazing or <br />browsing pressure was spread over a large area rather than concentrated on certain sites <br />as during the winter season. <br />Small Mammals. Four species of small mammals were trapped during the May 1974 trapping <br />program. These included the deer mouse (Peromyscus maniculatus), least chipmunk (Eutamias <br />minimus), long-tailed vole (Microtus longicaudus), and southern red -backed vole <br />(Clethrionomys gapperil. Deer mice appeared to be the most abundant small mammal on the <br />16 <br />