Date of Award:
Master of Science (MS)
John A. Bissonette
The effect of seasonal cattle grazing on a newly reintroduced
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
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
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.
Steinkamp, Melanie J., "The effect of seasonal cattle grazing on California bighorn sheep habitat use" (1990). All Graduate Theses and Dissertations. 2088.
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