We determined the diet contributions of grasses, forbs and shrubs for three herds of bighorn sheep along the Wasatch Front, Utah using stable isotope techniques and determined the electivity values for different forage species for four herds. Forbs were generally the most common forage eaten across all herds while shrubs were the least used forage resource. The Provo Peak and Mount Nebo herds used grasses, forbs and shrubs at proportions similar to other bighorn sheep populations across the west, while the Antelope Island herd used forbs at higher levels than any other local herd. Additionally, the herd on Antelope Island was analyzed to compare differential use by rams and ewes. Our results indicate that there was no significant difference in diet between sexes on Antelope Island. Bluebunch wheatgrass (Pseudoroegneria spicata) was a common species across all sites and was an important forage for all populations. Managers may consider these proportions when seeding in bighorn habitat improvement projects.

Vertebrate fossils have been discovered at several locations in the Bighorn Basin (Wyoming). The Virginia Museum of Natural History's (VMNH) digsite is located in the eastern part of the Bighorn Basin, in the Coyote Basin. Many scientists have worked within these basins trying to describe the stratigraphy. One question specifically asked is where the boundary between the Morrison Fm. (Jurassic) and the Cloverly Fm. (Cretaceous) lies. This new study attempted to show if the current method (Kvale, 1986) of determining the boundary is appropriate. The stratigraphy of the area was examined using Kvale, 1986, Ostrom, 1970, and Moberly, 1960's work in order to see which model was more robust. The fossils in the VMNH digsite were used to supplement the stratigraphic data in determining the age of specific beds. All of Ostrom's units were identified throughout the study area. There is some doubt as to whether the units would be acceptable outside of the Coyote Basin because of laterally discontinuity. Nevertheless, his description of units is satisfactory for the study area, and is more appropriate than other methods. The geologic age of the dinosaurs uncovered in the VMNH quarry is in agreement with the age determined stratigraphically. The VMNH site is below Ostrom's Unit II, which would place it in the Late Jurassic. The determination of the Jurassic/Cretaceous stratigraphic boundary has not been resolved. However, since the Pryor Conglomerate member of the Cloverly Fm. can be identified throughout this area, it is proposed as the Morrison Fm./Cloverly Fm. boundary. / Master of Science

No description available.

No description available.

The effect of seasonal cattle grazing on a newly reintroduced vii population of California bighorn sheep (Ovis canadensis californiana) in Big Cottonwood Canyon, Idaho, was studied. The hypothesis that bighorn sheep avoid cattle was tested. The issue of avoidance between bighorn sheep and livestock is arguable. Some studies have found that bighorn sheep avoid cattle while others have found no response of bighorn sheep to cattle. Evidence was found to document the avoidance of cattle by bighorn sheep. The size of the bighorn's home range and core area decreased with the movement of cattle into areas of high bighorn use. As cattle were moved into bighorn core areas, sheep responded by relocating. Bighorn sheep decreased their distance to escape terrain as cattle moved closer. The level and location of human disturbance on the study area did not have any effect on bighorn sheep movements or how sheep used the habitat. The severity of response observed is in marked contrast with the response of established bighorn populations to cattle. I suggest that newly reintroduced bighorn sheep are extremely sensitive to disturbance as a result of relocation trauma. Sensitivity may diminish over time.

No description available.

Russian thistle (Salsola tragus L.) invaded areas of native montane grassland important to winter survival of bighorn sheep (Ovis canadensis Shaw) were studied in Jasper National Park, Alberta, Canada. The biology of Russian thistle and its control in the Park were studied in the field and greenhouse. Russian thistle in grasslands were 9.1 cm tall with 37.5 seeds per plant, whereas larger plants in naturally disturbed habitats were 29.8 cm tall with 1562.4 seeds per plant. Plants travelled up to 4,180 m during dispersal. With soil seed contact, litter depth did not inhibit performance or survivability; without soil contact, thick litter reduced germination and plant performance. Russian thistle responded positively to increased greenhouse temperature and drier conditions. Seven control treatments involving herbicide, seeding mixes, hand pulling, and grazing exclusion were assessed. Grazing exclusion was the best field management option, increasing litter and biomass, while reducing Russian thistle density and biomass. / Land Reclamation and Remediation

Habitat use by mule deer, particularly in relation to use by cattle and by California bighorn sheep on the bighorn winter-spring ranges of Flatiron Mountain was studied from January 1968 through November 1969. Observations were made of (1) food habits, (2) forage production and utilization, (3) the effect of spring and summer utilization on subsequent forage production and (4) spatial and temporal distribution of range use. The results indicate that competition for forage between the native ungulates, deer and sheep, is largely obviated by differential habitat use. This may point to long term evolutionary ecological niche specialization. Some competition for forage occurs for a short period in the early spring when both ungulate species seek succulent new grass, the supply of which is at first limited. Cattle use of the winter-spring ranges was excessive and the diets of cattle and the native ungulates are similar, with the exception that utilization of grass by deer was less. Range use by cattle contributed to intra-specific cattle-deer competition on the grasslands in the spring and cattle-bighorn competition on the grasslands during the winter. The study of spring range utilization indicated that deer use was not detrimental to the 1969 annual forage production in areas used by deer. Spring range utilization by bighorn or bighorn in combination with deer reduced the standing crop of forage produced on the Agropyron spicatum dominated winter-spring ranges. Sheep utilization on South Slope during the summer, when forage growth was declining, further reduced the amount of forage available to the wintering bighorn population. / Land and Food Systems, Faculty of / Graduate

This study was undertaken to determine the interrelations among forage production and utilization, forage quality, forage availability, diet selection, and the subsequent impact of grazing by captive California bighorn sheep under controlled experimental conditions on an Artemisia - Agropyron plant community in southern interior British Columbia. Fourteen grasses, 58 forbs plus 18 trees and shrubs were available for grazing by the captive herd within a 42 ha experimental enclosure. Agropyron spicatum, Bromus tectorum and Artemisia tridentata were the dominant species on the site equaling 22.1, 9.5 and 6.7% of the cover respectively. Both annual and seasonal variations in plant species phenology, cover and botanical composition were evident among phenological groups, forage classes and individual species. Cover of grasses (51.4%) and forbs (24.1%) was highest in 1978 which was the wettest year, and it was lowest in 1979 which was the driest year equaling 34.2 and 12.8% for each group respectively. Cover of shrubs, and both cover and botanical composition of Agropyron spicatum varied little among years. Yields for total standing crop varied from 40.83 to 62.95 g/m² in 1977 and 1978 on the ungrazed areas in response to annual weather patterns. Fall regrowth was prevalent in 1978 and 1979 equaling 8.18 and 19.42 g/m² or 11.5 and 27.0% of the total herbage produced in each year respectively. Maximum availability of nutrients occurred in March and April each year, but from September through to November fall regrowth re-established nutrient levels to those recorded in the early growth stages for all plant species sampled. A total of 79 species consisting of 14 grasses, 47 forbs and 18 shrubs were observed in the diet of the experimental herd from 1977 to 1979. Grasses, forbs and shrubs comprised 66.6, 18.9 and 14.5% of the diet respectively over the 28 month study period. Agropyron spicatum was generally the most common plant found in the bighorn diet in all seasons, but this plant species typically occurred more frequently on the range than in the diet. Other grasses such as Festuca scabrella, Festuca idahoensis, Koeleria cristata and Stipa comata were preferred. Forbs were grazed most in summer (26.5 and 36.2%) and spring (19.2 and 18.4%) in 1977 and 1978 respectively. Perennial forbs were generally preferred but annual forbs were selected against by the bighorn sheep in all seasons. Browse was utilized most in winter and spring each year averaging 18.7 and 17.6% of the diet in each season respectively over the two year period. The dominant shrub, Artemisia tridentata was not preferred but most other browse species were. No consistent regressions could be established between forage consumption and corresponding nutritive quality of selected forage species. Balsamorhiza sagittata and Agropyron spicatum were least affected from grazing despite their importance in mountain sheep diet. Indeed, only leaf lengths differed among grazed and un-grazed Balsamorhiza sagittata plants and no significant differences were observed in basal diameters or the number of culms produced on grazed and ungrazed Agropyron spicatum plants after three years of grazing. Reductions in nearly all measured parameters were observed on grazed Koeleria cristata, Poa sandbergii, Stipa comata, Castilleja thompsonii, Lupinus sericeus and Erio- gonum niveum plants compared to ungrazed plants. Utilization of Amelanchier alnifolia was determined with three methods in 1977 and five methods in 1978. It was concluded that weight methods do not evaluate the impact of mountain sheep browsing any better than methods based on stem lengths. The long term effects of grazing by California bighorn sheep was evaluated from 1976 to 1983. Total cover remained virtually the same on the grazed (71.1 and 85.0%) and ungrazed (70.3 and 86.0%) areas between these two years respectively. Annual, perennial and individual plant species all reacted differently to grazing by mountain sheep. Cover of perennial grasses increased only slightly on both the grazed and protected areas between 1976 and 1983 but these differences were not statistically significant. No differences in either cover or botanical composition were observed between the grazed and ungrazed areas for Agropyron spicatum, Koeleria cristata or Poa sandbergii. Cover and botanical composition of forbs remained the same in 1983 compared to 1976 on the grazed areas. On the ungrazed areas, both cover and botanical composition of forbs increased over the same time period. Botanical composition of shrubs increased slightly on both the grazed and' ungrazed areas over the seven year period but cover for this group remained the same. Both Eriogonum niveum and Eriogonum heracleoides declined significantly on the areas grazed by bighorn sheep. Declines in both species were attributed to grazing pressure by the captive herd. / Land and Food Systems, Faculty of / Graduate

This project investigates federal, state and local agencies and organizations that are key sources of information about Peninsular bighorn sheep (Ovis canadensis cremnobates) to determine the extent of the agencies' environmental education and awareness programs related to the sheep. The agencies and organizations investigated include: Bureau of Land Management, Anza-Borrego Desert State Park, Living Desert Wildlife and Botanical Park, Bighorn Institute, Natural Science Collaborative of the Desert Region and California Desert Managers Group. Recommendations about future educational and interpretive programs are included.