Geology topics

V. C. Bleich

Publications and source records attributed to V. C. Bleich.

3 recordsLinked to original sources

USGS2003

Body weight and rumen-reticulum capacity in tule elk and mule deer

The relationship between body size and rumen-reticulum capacity among conspecific individuals is predicted to be isometric. We examined whether the relationship between body weight and rumen-reticulum capacity was isometric in adult male and female rule elk (Cervus elaphus nannodes) and in adult female mule deer (Odocoileus hemionus). We detected no effect of sex on this relationship in elk, and the slope of the regression was 1.0 for one measure of rumen-reticulum capacity and <1.0 for another. Among deer, the slope of the relationship was <1.0 in one measure of rumen-reticulum capacity, and we detected no relationship with the other.

Journal of Mammalogy↗

USGS2001

Restoration of bighorn sheep metapopulations in and near western national parks

Bighorn sheep ( Ovis canadensis ) once were ubiquitous in large areas, including lands now contained in the national parks of the Intermountain and Colorado Plateau regions of the United States. Due to catastrophic declines in the late 1800s and early 1900s, most extant populations now occur as small, isolated groups with a highly fragmented distribution. Three different subspecies of bighorn sheep were extirpated from 14 of 18 areas that are now managed by the National Park Service. We describe an eight-year plan to restore bighorn sheep to currently suitable historic habitats in the national parks within a six-state intermountain region of the western United States, 1991–1998. A seven-point program was recommended for each park unit that included: (1) survey the existing populations; (2) conduct a GIS-based habitat assessment to identify suitable habitat; (3) convene scientific advisory panels to review results of habitat assessment; (4) convene interagency panels to discuss metapopulation management and to plan the restoration(s); (5) draft interagency restoration and management plans; (6) conduct translocation(s); and (7) monitor the populations. We evaluated 38,781 km 2 of area; 32% (12,329 km 2 ) was potential habitat for bighorn sheep. The scientific advisory panels and the GIS modeling recommended bighorn restoration on 73 sites within these areas. By 1996, 36 of these sites (2,647 km 2 or 22% of the entire suitable area) were inhabited by bighorn sheep. By 1999, the translocated animals increased 25%, and restoration efforts will continue in many of the remaining sites.

Restoration Ecology↗

USGS2000

Desert bighorn sheep mortality due to presumptive type C botulism in California

During a routine telemetry flight of the Mojave Desert (California, USA) in August 1995, mortality signals were detected from two of 12 radio-collared female desert bighorn sheep ( Ovis canadensis ) in the vicinity of Old Dad Peak in San Bernardino County (California). A series of field investigations determined that at least 45 bighorn sheep had died near two artificial water catchments (guzzlers), including 13 bighorn sheep which had presumably drowned in a guzzler tank. Samples from water contaminated by decomposing bighorn sheep carcasses and hemolyzed blood from a fresh bighorn sheep carcass were tested for the presence of pesticides, heavy metals, strychnine, blue-green algae, Clostridium botulinum toxin, ethylene glycol, nitrates, nitrites, sodium, and salts. Mouse bioassay and enzyme-linked immunosorbent assay detected type C botulinum toxin in the hemolyzed blood and in fly larvae and pupae. This, coupled with negative results from other analyses, led us to conclude that type C botulinum poisoning was most likely responsible for the mortality of bighorn sheep outside the guzzler tank.

California↗