Threatened species of Ovis canadensis
Visualization of narrower problems
Name(s):
Endangered subspecies of Bighorn
Nature
The future of bighorn sheep depends on the preservation and improvement of critical native habitat range. Human activities on bighorn sheep habitat are the most widespread threat to bighorn sheep. Activies that reduce access tp prime habitat, cause bighorn sheep to, stop migration, and fragment from large herds into smaller herds. Human activities responsible for declines in sheep use of an area include hiking and backpacking, snow skiing, water skiing, fishing, motorbiking, four-wheel-drive vehicle use, construction and use of roads, urban development, and recreational development. When bighorn sheep are pushed from prime to marginal habitat, mortality usually increases and productivity decreases. Some herds have adapted to human activity. Bighorn sheep are poor competitors with other wild and domestic ungulates, and their range is diminishing under this pressure. The effect of domestic livestock grazing on bighorn sheep is controversial and depends on the proximity and population size of competing species. Domestic livestock have been reported to have little effect if they do not graze on critical bighorn sheep winter ranges. Nevertheless, extensive competition by livestock, especially on public lands, persists and is one of the reasons for the decline in density of bighorn sheep populations. Elk (Cervus elaphus) and deer (Odocoileus virginianus and O. hemionus) can also be serious competitors with bighorn sheep on marginal habitat.
Background
The former range of the bighorn sheep extended from the Northern Rocky Mountains of Canada south to the mainland of Mexico and Baja California. It is now found in relatively isolated pockets in the Coast and Cascade ranges and the Sierra Nevada, and in the Rocky Mountains south of the Peace River to Mexico. Bighorn sheep inhabit remote mountain and desert regions. They are restricted to semiopen, precipitous terrain with rocky slopes, ridges, and cliffs or rugged canyons. Forage, water, and escape terrain are the most important components of bighorn sheep habitat. Bighorn sheep are hunted by humans, traditionally for rams only and is further restricted by a 3/4 or full horn curl policy. In the last few years most states and provinces have adopted more stringent horn curl regulations. While the overall trend has been for more restrictive hunting seasons, in some cases local situations have dictated either sex or 1/2 curl ram seasons.
Incidence
In 1996: Under the Animal Collection Guidelines of the NMDGF Policy, the Aoudad (or barbary sheep) was listed as one of several animals to be "destroyed, following sighting in occupied bighorn sheep habitat" -- because of potential for disease transmission and forage competition with bighorn sheep.
Broader
Narrower
Type
(E) Emanations of other problems