Publications

survey of chronic sinusitis-induced skull anomalies in desert bighorn sheep.	bone anomalies were found in 20% of 630 skulls from desert bighorn sheep (ovis canadensis) representing populations of california bighorn (o canadensis californiana), lower california bighorn (o canadensis cremnobates), mexican bighorn (o canadensis mexicana), and nelson bighorn (o canadensis nelsoni) that are native to arizona, california, nevada, new mexico, and utah. the anomalies were extremely diverse, ranging from osteonecrosis within the matrix of the paranasal sinuses to extensive lysis ...	1981	7327996
the distribution of dermacentor hunteri and anaplasma sp. in desert bighorn sheep (ovis canadensis).	the ixodid tick dermacentor hunteri has been collected intermittently this century, primarily from desert bighorn sheep (ovis canadensis). anaplasma spp. are intraerythrocytic rickettsial parasites of ungulates and are vectored in the western united states by ticks of the genus dermacentor. we tested the hypotheses that d. hunteri would be found infesting all populations of desert bighorn, and that all infested populations would be seropositive for anaplasma sp. dermacentor hunteri was found on ...	1997	9057693
pasteurella spp. in sympatric bighorn and domestic sheep.	domestic sheep were sighted at different times from 1991 to 1993 on four nevada (usa) ranges occupied by bighorn sheep. nasal and pharyngeal swab samples were collected from both sheep species and cultured to determine if any strains of pasteurella spp. were shared on range conditions after contact of the two species. pasteurella spp. were isolated from all 38 bighorn sheep and 16 of 17 domestic sheep included in this study. the isolates were characterized on the bases of species, biotype, serot ...	1997	9249701
an ecologic study comparing distribution of pasteurella trehalosi and mannheimia haemolytica between sierra nevada bighorn sheep, white mountain bighorn sheep, and domestic sheep.	the prevalence and phenotypic variability of pasteurella and mannheimia isolates from sierra nevada bighorn sheep (ovis canadensis sierrae), white mountain bighorn sheep (ovis canadensis nelsoni), and domestic sheep (ovis aries) from california, usa, were compared. the white mountain bighorn sheep population had a recent history of pneumonia-associated mortality, whereas the sierra nevada bighorn sheep population had no recent history of pneumonia-associated mortality. the domestic sheep flocks ...	2009	19901369
population-specific vital rate contributions influence management of an endangered ungulate.	to develop effective management strategies for the recovery of threatened and endangered species, it is critical to identify those vital rates (survival and reproductive parameters) responsible for poor population performance and those whose increase will most efficiently change a population's trajectory. in actual application, however, approaches identifying key vital rates are often limited by inadequate demographic data, by unrealistic assumptions of asymptotic population dynamics, and of equ ...	2010	20945773
Translating effects of inbreeding depression on component vital rates to overall population growth in endangered bighorn sheep.	Evidence of inbreeding depression is commonly detected from the fitness traits of animals, yet its effects on population growth rates of endangered species are rarely assessed. We examined whether inbreeding depression was affecting Sierra Nevada bighorn sheep (Ovis canadensis sierrae), a subspecies listed as endangered under the U.S. Endangered Species Act. Our objectives were to characterize genetic variation in this subspecies; test whether inbreeding depression affects bighorn sheep vital ra ...	2011	22070275
evaluating apparent competition in limiting the recovery of an endangered ungulate.	predation can disproportionately affect endangered prey populations when generalist predators are numerically linked to more abundant primary prey. apparent competition, the term for this phenomenon, has been increasingly implicated in the declines of endangered prey populations. we examined the potential for apparent competition to limit the recovery of sierra nevada bighorn sheep (ovis canadensis sierrae), an endangered subspecies under the us endangered species act. using a combination of loc ...	2013	22791131
pcr assay detects mannheimia haemolytica in culture-negative pneumonic lung tissues of bighorn sheep (ovis canadensis) from outbreaks in the western usa, 2009-2010.	mannheimia haemolytica consistently causes severe bronchopneumonia and rapid death of bighorn sheep (ovis canadensis) under experimental conditions. however, bibersteinia trehalosi and pasteurella multocida have been isolated from pneumonic bighorn lung tissues more frequently than m. haemolytica by culture-based methods. we hypothesized that assays more sensitive than culture would detect m. haemolytica in pneumonic lung tissues more accurately. therefore, our first objective was to develop a p ...	2014	24171569