Dynamics of Pneumonia in a Bighorn Sheep Metapopulation

@inproceedings{Cassirer2007DynamicsOP,
  title={Dynamics of Pneumonia in a Bighorn Sheep Metapopulation},
  author={E. Frances Cassirer and Anthony R. E. Sinclair},
  year={2007}
}
Abstract We investigated the dynamics of 8 populations of a bighorn sheep (Ovis canadensis) metapopulation in Hells Canyon, USA from 1997 to 2003. Pneumonia was the most common cause (43%) of adult mortality and the primary factor limiting population growth. Cougar (Puma concolor) predation was the second most-frequent source (27%) of adult mortality but did not reduce the rate of population growth significantly. Most pneumonia-caused mortality occurred in fall and early winter and most cougar… 

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References

SHOWING 1-10 OF 36 REFERENCES

Ecological correlates of pneumonia epizootics in bighorn sheep herds

TLDR
The results suggest that bighorn sheep herds are rendered vulnerable to pneumonia principally through density-dependent factors, as well as through horizontal transmis - sion of Pasteurella spp.

Mountain lion predation of bighorn sheep in the Peninsular Ranges, California

TLDR
It is proposed that a sustained high level of predation by mountain lions, such as was seen during this study, may impede the recovery of this population of bighorn sheep.

Survival and cougar predation of translocated bighorn sheep in Arizona

TLDR
It is suggested that recent increases in cougar predation in most areas of Arizona may be responsible for declining bighorn sheep numbers, and recent population declines in mule deer may beresponsible for recent increases of cougar Predation in Arizona.

Cougar predation on bighorn sheep in southwestern Alberta during winter

TLDR
Cougar predation on bighorn sheep appears to be largely an individual, learned behaviour; most cougars rarely killed sheep, but some preyed heavily upon them.

Interactive effects of sublethal nematodes and nutritional status on snowshoe hare vulnerability to predation

TLDR
The effect of sublethal nematode parasitism on hare survival can be important if interactive with predation, and that synergistic effects of parasitism and nutrition may affect hares if food availability is limited is concluded.

Modeling demographic processes in an endangered population of bighorn sheep

TLDR
It is speculated that rescue effects, which are uncommon events for bighorn sheep, may be too rare or of inadequate magnitude under current conditions to effectively reverse bighORN sheep population declines.

PATHOLOGIC CHANGES AND MICROORGANISMS FOUND IN BIGHORN SHEEP DURING A STRESS-RELATED DIE-OFF

An all-age die-off of Rocky Mountain bighorn sheep (Ovis c. canadensis Shaw) occurred from late October 1980 through March 1981 in Waterton Canyon, Colorado, with a loss of 75 to 85% of the sheep.

EFFECTS OF AGE, SEX, DISEASE, AND DENSITY ON SURVIVAL OF BIGHORN SHEEP

TLDR
The data support the suggestion that where hunters remove many males older than 5 yr of age, the natural mortality of males increases at 3–5 yr, possibly because young males suffer a mortality cost of participating in rutting activity.

Interactions Between Pathogens and Hosts: Simulation of Pasteurellosis Epizootics in Bighorn Sheep Populations

TLDR
A discrete-time, stochastic simulation model to represent interactions between pathogens and bighorn sheep populations suggests that fluctuations in bighORN abundance can be plausibly explained by internal properties of host-pathogen interactions.

Test of a Modified Habitat Suitability Model for Bighorn Sheep

TLDR
Translocation of bighorn sheep is time, labor, and cost intensive and, therefore, high levels of success are desirable and the widely used habitat suitability model was modified to include additional factors which improved its usefulness in predicting appropriate translocation sites.