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A Review of Hypothesized Determinants Associated with Bighorn Sheep (Ovis canadensis) Die-Offs  [PDF]
David S. Miller,Eric Hoberg,Glen Weiser,Keith Aune,Mark Atkinson,Cleon Kimberling
Veterinary Medicine International , 2012, DOI: 10.1155/2012/796527
Abstract: Multiple determinants have been hypothesized to cause or favor disease outbreaks among free-ranging bighorn sheep (Ovis canadensis) populations. This paper considered direct and indirect causes of mortality, as well as potential interactions among proposed environmental, host, and agent determinants of disease. A clear, invariant relationship between a single agent and field outbreaks has not yet been documented, in part due to methodological limitations and practical challenges associated with developing rigorous study designs. Therefore, although there is a need to develop predictive models for outbreaks and validated mitigation strategies, uncertainty remains as to whether outbreaks are due to endemic or recently introduced agents. Consequently, absence of established and universal explanations for outbreaks contributes to conflict among wildlife and livestock stakeholders over land use and management practices. This example illustrates the challenge of developing comprehensive models for understanding and managing wildlife diseases in complex biological and sociological environments. 1. Introduction Effective management and conservation of wildlife populations can be undermined by multiple causes. These include decreased and altered habitat and other direct anthropogenic effects, climate change, competition and predation from nonnative wildlife and domestic species, demographic challenges associated with small populations, multiple, incompatible management objectives for sympatric species or their habitat, and exposure to native and exotic infectious agents [1–4]. The consequences and interactions of these variables are difficult to understand and predict, and may vary by circumstances. This uncertainty, particularly when it occurs in complex sociological environments where stakeholders have differing values and objectives, presents substantial challenges for decision makers. In such uncertain environments, the absence of data and differing values can result in polarized debate among stakeholders. It can also serve as an impediment to the acquisition of data that would contribute to effective management. Respiratory disease outbreaks in bighorn sheep (Ovis canadensis) illustrate the challenge of identifying and managing disease in valued wildlife populations, where stakeholder perceptions and values clash [5]. Bighorn sheep are highly valued for recreational, ecological, philosophical, spiritual, and other reasons [6]. Bighorns have experienced a population decline of two orders of magnitude subsequent to 19th century settlement of western North
Puma predation on radiocollared and uncollared bighorn sheep
Sean M Clemenza, Esther S Rubin, Christine K Johnson, Randall A Botta, Walter M Boyce
BMC Research Notes , 2009, DOI: 10.1186/1756-0500-2-230
Abstract: Three pumas killed 23 bighorn sheep over the course of the study, but they did not preferentially prey on marked (radiocollared) versus unmarked bighorn sheep. Predation occurred primarily during crepuscular and nighttime hours, and 22 kill sites were identified by the occurrence of 2 or more consecutive puma GPS locations (a cluster) within 200 m of each other at 1900, 0000, and 0600 h.We tested the "conspicuous individual hypothesis" and found that there was no difference in puma predation upon radiocollared and uncollared bighorn sheep. Pumas tended to move long distances before and after kills, but their movement patterns immediately post-kill were much more restricted. Researchers can exploit this behaviour to identify puma kill sites and investigate prey selection by designing studies that detect puma locations that are spatially clustered between dusk and dawn.Pumas (Puma concolor) are known predators of bighorn sheep (Ovis canadensis) in North America, but puma behaviour and movements associated with these predation events are poorly understood. Ross et al. [1] found predation on Rocky Mountain bighorn sheep to be an individual behaviour in Alberta, and Logan and Sweanor [2] and Ernest et al. [3] also presented evidence for differences in the frequency that individual pumas killed desert bighorn sheep in the southwestern United States. Although these studies identified individual pumas that selectively killed bighorn sheep, they left important questions unanswered. During ongoing studies of pumas and endangered bighorn sheep in the Peninsular Ranges of California, we radiocollared 3 pumas (1 female and her 2 offspring) who subsequently each killed multiple bighorn sheep (total ≥ 23). This gave us the opportunity to critically evaluate whether or not pumas selectively preyed on radiocollared versus uncollared bighorn sheep (because marked animals are more conspicuous), and to examine movement patterns at and around bighorn sheep kill sites.The Peninsular Rang
Shared Bacterial and Viral Respiratory Agents in Bighorn Sheep (Ovis canadensis), Domestic Sheep (Ovis aries), and Goats (Capra hircus) in Montana  [PDF]
David S. Miller,Glen C. Weiser,Keith Aune,Brent Roeder,Mark Atkinson,Neil Anderson,Thomas J. Roffe,Kim A. Keating,Phillip L. Chapman,Cleon Kimberling,Jack Rhyan,P. Ryan Clarke
Veterinary Medicine International , 2011, DOI: 10.4061/2011/162520
Abstract: Transmission of infectious agents from livestock reservoirs has been hypothesized to cause respiratory disease outbreaks in bighorn sheep (Ovis canadensis), and land management policies intended to limit this transmission have proven controversial. This cross-sectional study compares the infectious agents present in multiple populations of bighorn sheep near to and distant from their interface with domestic sheep (O. aries) and domestic goat (Capra hircus) and provides critical baseline information needed for interpretations of cross-species transmission risks. Bighorn sheep and livestock shared exposure to Pasteurellaceae, viral, and endoparasite agents. In contrast, although the impact is uncertain, Mycoplasma sp. was isolated from livestock but not bighorn sheep. These results may be the result of historic cross-species transmission of agents that has resulted in a mosaic of endemic and exotic agents. Future work using longitudinal and multiple population comparisons is needed to rigorously establish the risk of outbreaks from cross-species transmission of infectious agents. 1. Introduction Bighorn sheep (Ovis canadensis) experienced substantial decreases in population numbers and range in the 19th and the early 20th centuries, and subsequent recovery efforts have often been limited by large-scale die-offs [1–3]. These initial population declines were associated with settlement of western North America and were attributed to unregulated hunting, competition for forage with domestic sheep (O. aries) and other livestock, and disruption of historic bighorn sheep migration patterns due to development. Clinical disease was apparently unimportant or was underreported in these early declines, though die-offs of bighorn sheep associated with sheep scab (Psoroptes sp.) were reported following settlement [4, 5]. Bighorn sheep die-offs associated with pneumonia were reported in the 1920s and 1930s [6–10]. These early reports and subsequent work largely focused on lungworm (Protostrongylus sp.) as the primary infectious agent, although the involvement of Pasteurella sp., Corynebacterium pyogenes (currently Arcanobacterium pyogenes), and other host and environmental determinants were also noted as potential causes of respiratory disease. Subsequently, inconsistent association of lungworm with respiratory disease in bighorn sheep, as well as further evidence for Pasteurella sp. as the cause of pneumonia, led to a focus on pasteurellosis as a cause of respiratory disease outbreaks [11–14]. This research included evidence that Pasteurella sp. strains from clinically
Local Extinction and Unintentional Rewilding of Bighorn Sheep (Ovis canadensis) on a Desert Island  [PDF]
Benjamin T. Wilder, Julio L. Betancourt, Clinton W. Epps, Rachel S. Crowhurst, Jim I. Mead, Exequiel Ezcurra
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0091358
Abstract: Bighorn sheep (Ovis canadensis) were not known to live on Tiburón Island, the largest island in the Gulf of California and Mexico, prior to the surprisingly successful introduction of 20 individuals as a conservation measure in 1975. Today, a stable island population of ~500 sheep supports limited big game hunting and restocking of depleted areas on the Mexican mainland. We discovered fossil dung morphologically similar to that of bighorn sheep in a dung mat deposit from Mojet Cave, in the mountains of Tiburón Island. To determine the origin of this cave deposit we compared pellet shape to fecal pellets of other large mammals, and extracted DNA to sequence mitochondrial DNA fragments at the 12S ribosomal RNA and control regions. The fossil dung was 14C-dated to 1476–1632 calendar years before present and was confirmed as bighorn sheep by morphological and ancient DNA (aDNA) analysis. 12S sequences closely or exactly matched known bighorn sheep sequences; control region sequences exactly matched a haplotype described in desert bighorn sheep populations in southwest Arizona and southern California and showed subtle differentiation from the extant Tiburón population. Native desert bighorn sheep previously colonized this land-bridge island, most likely during the Pleistocene, when lower sea levels connected Tiburón to the mainland. They were extirpated sometime in the last ~1500 years, probably due to inherent dynamics of isolated populations, prolonged drought, and (or) human overkill. The reintroduced population is vulnerable to similar extinction risks. The discovery presented here refutes conventional wisdom that bighorn sheep are not native to Tiburón Island, and establishes its recent introduction as an example of unintentional rewilding, defined here as the introduction of a species without knowledge that it was once native and has since gone locally extinct.
Use of Exposure History to Identify Patterns of Immunity to Pneumonia in Bighorn Sheep (Ovis canadensis)  [PDF]
Raina K. Plowright, Kezia Manlove, E. Frances Cassirer, Paul C. Cross, Thomas E. Besser, Peter J. Hudson
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0061919
Abstract: Individual host immune responses to infectious agents drive epidemic behavior and are therefore central to understanding and controlling infectious diseases. However, important features of individual immune responses, such as the strength and longevity of immunity, can be challenging to characterize, particularly if they cannot be replicated or controlled in captive environments. Our research on bighorn sheep pneumonia elucidates how individual bighorn sheep respond to infection with pneumonia pathogens by examining the relationship between exposure history and survival in situ. Pneumonia is a poorly understood disease that has impeded the recovery of bighorn sheep (Ovis canadensis) following their widespread extirpation in the 1900s. We analyzed the effects of pneumonia-exposure history on survival of 388 radio-collared adults and 753 ewe-lamb pairs. Results from Cox proportional hazards models suggested that surviving ewes develop protective immunity after exposure, but previous exposure in ewes does not protect their lambs during pneumonia outbreaks. Paradoxically, multiple exposures of ewes to pneumonia were associated with diminished survival of their offspring during pneumonia outbreaks. Although there was support for waning and boosting immunity in ewes, models with consistent immunizing exposure were similarly supported. Translocated animals that had not previously been exposed were more likely to die of pneumonia than residents. These results suggest that pneumonia in bighorn sheep can lead to aging populations of immune adults with limited recruitment. Recovery is unlikely to be enhanced by translocating na?ve healthy animals into or near populations infected with pneumonia pathogens.
Habitat use by desert bighorn sheep in sonora, México
Tarango, L. A.,Krausman, R.,Valdez, R.
Pirineos : Revista de Ecología de Monta?a , 2002,
Abstract: The use of habitat components by desert bighorn sheep (Ovis canadensis) was examined to explain sexual segregation of sheep in Sierra el Viejo, Sonora, Mexico. We evaluated 265 plots used by bighorns and 278 random plots from April 1997 to December 1998. Groups of segregated males and females preferred the elephant tree (Bursera microphylla)-salvia (Salvia mellifera)-limber bush (Jatropha cuneata) association (ESL) and avoided the foothill palo verde (Cercidium microphyllum)-desert ironwood (Olneya tesota) association (FDD. Segregated females selected the ocotillo (Fouquieria splendens)-desert agave (Agave spp.yhop bush (Dodonoea viscosa) (OAH) vegetation association, formed larger groups, were closer to escape terrain, and occupied more rugged areas during autumn and spring than males. Segregated females selected areas that provided more opportunities to evade predation than did males. [fr] Nous avons étudié les différents composants de l'utilisation de l'habitat par le mouflon américain (Ovis canadensis) afin d'expliquer sa ségrégation sexuelle dans la Sierra el Viejo, à Sonora, Mexique. D'avril 1997 à Décembre 1998, on a évalué 265 parcelles utilisées par les mouflons et 278 parcelles au hasard. Différents groupes séparés de males et femelles préféraient l'association (ESL) formée par l'arbre Bursera microphylla, la sauge (Salvia mellifera) et l'arbuste Jatropa cuneata et ils évitaient l'association (FDD composée du Cercidium microphyllum et /'Olneya tesota. Les groupes de femelles sélectionaient l'association végétale (OAH) de Fouquieria splendens. Agave spp. et l'arbuste Dodonoea viscosa; et par rapport aux males, elles formaient de plus grands groupes, étaient plus proches de la zone de fuite et elles occupaient des terrains plus accidentés en automne et au printemps. Les groupes de femelles, plus que les males, cherchaient des zones avec moins de risque de prédation. [es] Se examinó el uso del hábitat del muflón americano Ovis canadensis para explicar su segregación sexual en Sierra el Viejo, Sonora, Méjico. Se establecieron 265 parcelas usadas por el muflón y 278 tomadas al azar, desde abril de 1997 hasta diciembre de 1998. Los grupos segregados de machos y hembras prefirieron la asociación (ESL) torote blanco (Bursera microphyllaj-sn/z^m (Salvia mellifera)- sangreado (Jatropha cuneata) y evitaron la asociación (FDI) palo verde (Cercidium microphyllum)-palo fierro (Olneya tesota). Los grupos de hembras seleccionaron la asociación ocotillo (Fouquieria splendens)-ágave (Agave spp.)- chirca (Dodonaea viscosa) (OAH); formaron grandes grupos, estando
Estudio morfológico de los cromosomas del borrego Cimarrón (Otis canadensis), Tabasco o Pelibuey (Ovis aries) y su cruza  [cached]
Ana Carmen Delgadillo Calvillo,Octavio Mejía Villanueva,José Manuel Berruecos Villalobos,Carlos Gustavo Vásquez Peláez
Veterinaria México , 2003,
Abstract: En este trabajo se determinó y comparó por vez primera el número diploide (2n) y morfología cromosómica del borrego híbrido producto de la cruza interespecífica entre borrego Cimarrón (Ovis canadensis), y borrego Pelibuey (Ovis aries). Se determinó el cariotipo del borrego híbrido que tiene un número cromosómico de 2n = 54, formado por tres pares de submetacéntricos grandes y 23 pares de cromosomas acrocéntricos que varían en tama o. El arreglo cromosómico es igual en las tres especies. El híbrido de esta cruza es fértil y abre la posibilidad de buscar alternativas para la protección y conservación del borrego Cimarrón, que actualmente es considerado por el CITES dentro del apéndice II como especie amenazada y por la NOM-ECOL-059/94, como sujeta a protección especial.
Seasonal Foraging Ecology of Non-Migratory Cougars in a System with Migrating Prey  [PDF]
L. Mark Elbroch, Patrick E. Lendrum, Jesse Newby, Howard Quigley, Derek Craighead
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0083375
Abstract: We tested for seasonal differences in cougar (Puma concolor) foraging behaviors in the Southern Yellowstone Ecosystem, a multi-prey system in which ungulate prey migrate, and cougars do not. We recorded 411 winter prey and 239 summer prey killed by 28 female and 10 male cougars, and an additional 37 prey items by unmarked cougars. Deer composed 42.4% of summer cougar diets but only 7.2% of winter diets. Males and females, however, selected different proportions of different prey; male cougars selected more elk (Cervus elaphus) and moose (Alces alces) than females, while females killed greater proportions of bighorn sheep (Ovis canadensis), pronghorn (Antilocapra americana), mule deer (Odocoileus hemionus) and small prey than males. Kill rates did not vary by season or between males and females. In winter, cougars were more likely to kill prey on the landscape as: 1) elevation decreased, 2) distance to edge habitat decreased, 3) distance to large bodies of water decreased, and 4) steepness increased, whereas in summer, cougars were more likely to kill in areas as: 1) elevation decreased, 2) distance to edge habitat decreased, and 3) distance from large bodies of water increased. Our work highlighted that seasonal prey selection exhibited by stationary carnivores in systems with migratory prey is not only driven by changing prey vulnerability, but also by changing prey abundances. Elk and deer migrations may also be sustaining stationary cougar populations and creating apparent competition scenarios that result in higher predation rates on migratory bighorn sheep in winter and pronghorn in summer. Nevertheless, cougar predation on rare ungulates also appeared to be influenced by individual prey selection.
Genetic linkage map of a wild genome: genomic structure, recombination and sexual dimorphism in bighorn sheep
Jocelyn Poissant, John T Hogg, Corey S Davis, Joshua M Miller, Jillian F Maddox, David W Coltman
BMC Genomics , 2010, DOI: 10.1186/1471-2164-11-524
Abstract: Bighorn sheep population-specific maps differed slightly in contiguity but were otherwise very similar in terms of genomic structure and recombination rates. The joint analysis of the two pedigrees resulted in a highly contiguous map composed of 247 microsatellite markers distributed along all 26 autosomes and the X chromosome. The map is estimated to cover about 84% of the bighorn sheep genome and contains 240 unique positions spanning a sex-averaged distance of 3051 cM with an average inter-marker distance of 14.3 cM. Marker synteny, order, sex-averaged interval lengths and sex-averaged total map lengths were all very similar between sheep species. However, in contrast to domestic sheep, but consistent with the usual pattern for a placental mammal, recombination rates in bighorn sheep were significantly greater in females than in males (~12% difference), resulting in an autosomal female map of 3166 cM and an autosomal male map of 2831 cM. Despite differing genome-wide patterns of heterochiasmy between the sheep species, sexual dimorphism in recombination rates was correlated between orthologous intervals.We have developed a first-generation bighorn sheep linkage map that will facilitate future studies of the genetic architecture of trait variation in this species. While domestication has been hypothesized to be responsible for the elevated mean recombination rate observed in domestic sheep, our results suggest that it is a characteristic of Ovis species. However, domestication may have played a role in altering patterns of heterochiasmy. Finally, we found that interval-specific patterns of sexual dimorphism were preserved among closely related Ovis species, possibly due to the conserved position of these intervals relative to the centromeres and telomeres. This study exemplifies how transferring genomic resources from domesticated species to close wild relative can benefit evolutionary ecologists while providing insights into the evolution of genomic structure and
Otters (Lutra lutra) Hunted as Beavers (Castor canadensis) in Finland
Skarén U.
IUCN Otter Specialist Group Bulletin , 2003,
Abstract: Otters (Lutra lutra) are protected in Finland, but it is legal to hunt beavers (Castor canadensis).
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