scholarly journals Habitat use and social mixing between groups of resident and augmented bighorn sheep

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Rusty W. Robinson ◽  
Jericho C. Whiting ◽  
Justin M. Shannon ◽  
Daniel D. Olson ◽  
Jerran T. Flinders ◽  
...  
Keyword(s):  
Habitat Use ◽  
Species Conservation ◽  
Source Area ◽  
Bighorn Sheep ◽  
Ovis Canadensis ◽  
Range Use ◽  
Adult Females ◽  
Social Mixing ◽  
Utilization Distributions ◽  
Two Populations

Abstract Monitoring dispersal, habitat use, and social mixing of released ungulates is crucial for successful translocation and species conservation. We monitored 127 female bighorn sheep (Ovis canadensis) released in three populations from 2000 to 2009 to investigate if augmented bighorns expanded and shifted seasonal ranges, used different habitat compared with resident females, and if animals mixed socially. Augmented bighorns in all populations expanded range use compared with residents by shifting utilization distributions. Size of utilization distributions, however, were smaller for augmented females compared with residents in all areas except one. Overlap of seasonal utilization distributions between augmented and resident bighorns and use of slope and elevation differed across populations. In two populations, differences in size and overlap of seasonal utilization distributions and use of slope and elevation supported the hypothesis that habitat use of bighorns in their source area influenced their habitat use after release. Mixing between resident and augmented adult females occurred on average during only 21% of sightings and was similar across populations. Our results clarify how augmented bighorns mix with resident animals and how habitat use is modified following augmentations. Such information is needed to improve bighorn sheep augmentations and can be applied to augmentations of other ungulates.

scholarly journals Linking population performance to nutritional condition in an alpine ungulate

2020 ◽  
Vol 101 (5) ◽  
pp. 1244-1256 ◽  
Author(s):  
Thomas R Stephenson ◽  
David W German ◽  
E Frances Cassirer ◽  
Daniel P Walsh ◽  
Marcus E Blum ◽  
...  
Keyword(s):  
Body Fat ◽  
Bighorn Sheep ◽  
Nutritional Condition ◽  
Ovis Canadensis ◽  
Population Increase ◽  
Overwinter Survival ◽  
Fat Reserves ◽  
Adult Females ◽  
Free Body

Abstract Bighorn sheep (Ovis canadensis) can live in extremely harsh environments and subsist on submaintenance diets for much of the year. Under these conditions, energy stored as body fat serves as an essential reserve for supplementing dietary intake to meet metabolic demands of survival and reproduction. We developed equations to predict ingesta-free body fat in bighorn sheep using ultrasonography and condition scores in vivo and carcass measurements postmortem. We then used in vivo equations to investigate the relationships between body fat, pregnancy, overwinter survival, and population growth in free-ranging bighorn sheep in California and Nevada. Among 11 subpopulations that included alpine winter residents and migrants, mean ingesta-free body fat of lactating adult females during autumn ranged between 8.8% and 15.0%; mean body fat for nonlactating females ranged from 16.4% to 20.9%. In adult females, ingesta-free body fat > 7.7% during January (early in the second trimester) corresponded with a > 90% probability of pregnancy and ingesta-free body fat > 13.5% during autumn yielded a probability of overwinter survival > 90%. Mean ingesta-free body fat of lactating females in autumn was positively associated with finite rate of population increase (λ) over the subsequent year in bighorn sheep subpopulations that wintered in alpine landscapes. Bighorn sheep with ingesta-free body fat of 26% in autumn and living in alpine environments possess energy reserves sufficient to meet resting metabolism for 83 days on fat reserves alone. We demonstrated that nutritional condition can be a pervasive mechanism underlying demography in bighorn sheep and characterizes the nutritional value of their occupied ranges. Mountain sheep are capital survivors in addition to being capital breeders, and because they inhabit landscapes with extreme seasonal forage scarcity, they also can be fat reserve obligates. Quantifying nutritional condition is essential for understanding the quality of habitats, how it underpins demography, and the proximity of a population to a nutritional threshold.

scholarly journals An Analysis of Composition, Distribution, and Habitat Use of Reintroduced Desert Bighorn Sheep in Arches National Park, Utah

1989 ◽  
Vol 13 ◽  
pp. 5-6
Author(s):  
C. Haas ◽  
Gar Workman
Keyword(s):  
Habitat Use ◽  
National Park ◽  
Social Dynamics ◽  
National Park Service ◽  
Bighorn Sheep ◽  
Ovis Canadensis ◽  
Desert Bighorn Sheep ◽  
Use Patterns ◽  
Habitat Analysis ◽  
Park Service

The ecology of a reintroduced population of desert bighorn sheep (Ovis canadensis nelsoni} is being investigated in Arches National Park. National Park Service objectives are: (1) determine general ecological parameters, including population and social dynamics, seasonal distribution and habitat use patterns, and general health characteristics; and (2) develop a comprehensive program of habitat analysis and evaluation that can be used to determine habitat suitability and identify transplant sites in other National Park Service units.

scholarly journals Impact of Mycoplasma ovipneumoniae on juvenile bighorn sheep (Ovis canadensis) survival in the northern Basin and Range ecosystem

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10710
Author(s):  
Robert S. Spaan ◽  
Clinton W. Epps ◽  
Rachel Crowhurst ◽  
Donald Whittaker ◽  
Mike Cox ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Survival Probability ◽  
Population Genetic ◽  
Bighorn Sheep ◽  
Basin And Range ◽  
Ovis Canadensis ◽  
Juvenile Survival ◽  
Adult Females ◽  
Mycoplasma Ovipneumoniae

Determining the demographic impacts of wildlife disease is complex because extrinsic and intrinsic drivers of survival, reproduction, body condition, and other factors that may interact with disease vary widely. Mycoplasma ovipneumoniae infection has been linked to persistent mortality in juvenile bighorn sheep (Ovis canadensis), although mortality appears to vary widely across subspecies, populations, and outbreaks. Hypotheses for that variation range from interactions with nutrition, population density, genetic variation in the pathogen, genetic variation in the host, and other factors. We investigated factors related to survival of juvenile bighorn sheep in reestablished populations in the northern Basin and Range ecosystem, managed as the formerly-recognized California subspecies (hereafter, “California lineage”). We investigated whether survival probability of 4-month juveniles would vary by (1) presence of M. ovipneumoniae-infected or exposed individuals in populations, (2) population genetic diversity, and (3) an index of forage suitability. We monitored 121 juveniles across a 3-year period in 13 populations in southeastern Oregon and northern Nevada. We observed each juvenile and GPS-collared mother semi-monthly and established 4-month capture histories for the juvenile to estimate survival. All collared adult females were PCR-tested at least once for M. ovipneumoniae infection. The presence of M. ovipneumoniae-infected juveniles was determined by observing juvenile behavior and PCR-testing dead juveniles. We used a known-fate model with different time effects to determine if the probability of survival to 4 months varied temporally or was influenced by disease or other factors. We detected dead juveniles infected with M. ovipneumoniae in only two populations. Derived juvenile survival probability at four months in populations where infected juveniles were not detected was more than 20 times higher. Detection of infected adults or adults with antibody levels suggesting prior exposure was less predictive of juvenile survival. Survival varied temporally but was not strongly influenced by population genetic diversity or nutrition, although genetic diversity within most study area populations was very low. We conclude that the presence of M. ovipneumoniae can cause extremely low juvenile survival probability in translocated bighorn populations of the California lineage, but found little influence that genetic diversity or nutrition affect juvenile survival. Yet, after the PCR+ adult female in one population died, subsequent observations found 11 of 14 ( 79%) collared adult females had surviving juveniles at 4-months, suggesting that targeted removals of infected adults should be evaluated as a management strategy.

Numbers of lungworm larvae in feces of bighorn sheep: yearly changes, influence of host sex, and effects on host survival

1991 ◽  
Vol 69 (3) ◽  
pp. 547-554 ◽  
Author(s):  
Marco Festa-Bianchet
Keyword(s):  
Infection Intensity ◽  
Bighorn Sheep ◽  
Ovis Canadensis ◽  
Seasonal Migration ◽  
Herd Health ◽  
Spring Precipitation ◽  
Adult Females ◽  
Host Sex ◽  
Larval Count ◽  
Study Population

The number of Protostrongylus spp. first-stage larvae in the feces of marked bighorn sheep (Ovis canadensis) was monitored from 1981 to 1988 in southwestern Alberta. Prevalence of infection was 100%. Counts were not correlated with spring precipitation, winter temperature, or number of female sheep in the study population. Percent lamb survival and average counts were correlated only when years affected by the occurrence of a pneumonia epizootic were excluded. In the years before the epizootic, but not afterwards, lambs born to females with high larval counts were less likely to survive to weaning or to 1 year of age than lambs born to females with low counts. Fecal larval counts from the same female in successive years were weakly correlated, and tended to change towards the mean for all females. Counts were affected by host reproduction but not by seasonal migration, and did not affect host survival. Among lambs and yearlings, males had higher counts than females. Lambs had higher counts than adult females. There were no age-specific differences among adult females. The larval count from female lambs was correlated with that from their mother but not that from male lambs. Heart girth of female lambs was correlated with their larval count and that of their mother. I suggest that larval counts are affected by infection intensity and body condition, do not predict pneumonia epizootics, and have limited reliability as an index of herd health.

scholarly journals Habitat Utilization, Interspefic Interactions and Status of a Recolonized Population of Bighorn Sheep at a Wild Horse Range

1987 ◽  
Vol 11 ◽  
pp. 11-16
Author(s):  
Sanford Schemnitz ◽  
Kevin Coates
Keyword(s):  
Habitat Use ◽  
Foraging Behavior ◽  
Food Habits ◽  
Activity Patterns ◽  
Rocky Mountain ◽  
Bighorn Sheep ◽  
Management Program ◽  
Ovis Canadensis ◽  
Wild Horse ◽  
Recreation Area

Data have been collected from 05-86 to 11-87 to aid in the development of a management program for Rocky Mountain bighorn sheep (Ovis canadensis canadensis) at Bighorn Canyon National Recreation Area (BICA). The purpose of this report is to summarize progress toward completing the following Objectives: 1. Determine the size, and age/sex composition of the sheep herd at BICA; determine the general health of the herd. 2. Analyze the seasonal food habits of sheep and wild horses; analyze the dietary overlap of these species; analyze the foraging behavior of sheep in habitats occupied exclusively by sheep and compare with the foraging behavior of sheep in habitats used in common with horses and/or humans. 3. Analyze seasonal habitat use throughout the annual cycle; analyze activity patterns during all daylight hours and relate to habitat use; identify and describe sensitive use areas for consideration in future sheep management programs. 4. Determine the total habitat potential of BICA.

scholarly journals Brucellosis in Captive Rocky Mountain Bighorn Sheep (Ovis canadensis) Caused by Brucella abortus Biovar 4

2004 ◽  
Vol 40 (2) ◽  
pp. 311-315 ◽  
Author(s):  
Terry J. Kreeger ◽  
Walter E. Cook ◽  
William H. Edwards ◽  
Todd Cornish
Keyword(s):  
Brucella Abortus ◽  
Rocky Mountain ◽  
Bighorn Sheep ◽  
Ovis Canadensis

scholarly journals Desert Bighorn Sheep: Changes in Genetic Variation Over Time and the Impact of Merging Populations

2014 ◽  
Vol 5 (1) ◽  
pp. 3-13 ◽  
Author(s):  
Philip W. Hedrick ◽  
John D. Wehausen
Keyword(s):  
Genetic Variation ◽  
New Mexico ◽  
Monitoring And Evaluation ◽  
Bighorn Sheep ◽  
Ovis Canadensis ◽  
Mexican Population ◽  
Desert Bighorn Sheep ◽  
Two Generations ◽  
The Impact ◽  
Over Time

Abstract Founder effects, genetic bottlenecks, and genetic drift in general can lead to low levels of genetic diversity, which can influence the persistence of populations. We examine genetic variation in two populations of desert bighorn sheep Ovis canadensis from New Mexico and Mexico to measure change over time and evaluate the impact of introducing individuals from one population into the other. Over about three generations, the amount of genetic variation in the New Mexico population increased. In contrast, over about two generations the amount of genetic variation in the Mexican population decreased by a great extent compared with an estimate from another Mexican population from which it is primarily descended. The potential reasons for these changes are discussed. In addition, although both populations have low genetic variation, introduction of Mexican rams into the New Mexico population might increase the amount of genetic variation in the New Mexico population. Overall, it appears that management to increase genetic variation might require substantial detailed monitoring and evaluation of ancestry from the different sources and fitness components.

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