Endangered Peninsular Bighorn Sheep
ENDANGERED SPECIES PROFILE
WHO? Peninsular bighorn sheep (Ovis canadensis)
WHAT? Listed as a federally endangered species
WHEN? March 18, 1998
WHERE? In the United States (from Palm Springs, CA south to the U.S./Mexico international border)
WHY? Substantial population declines due to disease, predation, habitat loss, and human disturbance
Summary of endangered listing
Six years after they were originally proposed for endangered listing, on March 18, 1998, the United States Peninsular Ranges population of desert bighorn sheep was federally listed as an endangered species pursuant to the Endangered Species Act (ESA) of 1973, as amended. The U.S. Fish & Wildlife Service (overseers of the Federal ESA) determined that Peninsular bighorn sheep are in danger of extinction throughout a significant portion of their range due to: (1) disease; (2) insufficient lamb recruitment; (3) habitat loss, degradation, and fragmentation by urban and commercial development; and (4) predation coinciding with low population numbers.
Peninsular bighorn habitat and numbers
Peninsular bighorn sheep inhabit dry, rocky, low-elevation desert slopes, canyons, and washes from the San Jacinto and Santa Rosa mountains near Palm Springs, California south into Baja California, Mexico. These sheep are known as low elevation bighorn because they use habitat from 400' - 4,000' elevation. Within the U.S., Peninsular bighorn are distributed in a metapopulation structure (a group of subpopulations linked by the movement of a limited number of animals) comprised of at least 8 demes or subpopulations. Helicopter surveys conducted in the fall of 2006 indicated that approximately 800 Peninsular bighorn inhabit the U.S. and the most recent surveys of Mexico estimate the Baja California Peninsular bighorn population at 2,000-2,500 bighorn. In the 1970s, Peninsular bighorn sheep were estimated to number nearly 1,200 in the U.S. and 4,500-7,800 in Baja California. Because there are currently considerably more animals in Mexico than in the U.S., and the Mexican government has established a new conservation program for managing Peninsular bighorn in Mexico, only the U.S. population was included in the endangered listing.
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http://www.bighorninstitute.org/endangered.htm