Campus Units
Natural Resource Ecology and Management
Document Type
Article
Publication Version
Published Version
Publication Date
2-7-2014
Journal or Book Title
PloS ONE
Volume
9
Issue
2
First Page
e88271
DOI
10.1371/journal.pone.0088271
Abstract
Estimating survival and documenting causes and timing of mortality events in neonate bighorn sheep (Ovis canadensis) improves understanding of population ecology and factors influencing recruitment. During 2010–2012, we captured and radiocollared 74 neonates in the Black Hills, South Dakota, of which 95% (70) died before 52 weeks of age. Pneumonia (36%) was the leading cause of mortality followed by predation (30%). We used known fate analysis in Program MARK to estimate weekly survival rates and investigate the influence of intrinsic variables on 52-week survival. Model {S1 wk, 2–8 wks, >8 wks} had the lowest AICc (Akaike’s Information Criterion corrected for small sample size) value, indicating that age (3-stage age-interval: 1 week, 2–8 weeks, and >8 weeks) best explained survival. Weekly survival estimates for 1 week, 2–8 weeks, and >8 weeks were 0.81 (95% CI = 0.70–0.88), 0.86 (95% CI = 0.81–0.90), and 0.94 (95% CI = 0.91–0.96), respectively. Overall probability of surviving 52 weeks was 0.02 (95% CI = 0.01–0.07). Of 70 documented mortalities, 21% occurred during the first week, 55% during weeks 2–8, and 23% occurred >8 weeks of age. We found pneumonia and predation were temporally heterogeneous with lambs most susceptible to predation during the first 2–3 weeks of life, while the greatest risk from pneumonia occurred from weeks 4–8. Our results indicated pneumonia was the major factor limiting recruitment followed by predation. Mortality from predation may have been partly compensatory to pneumonia and its effects were less pronounced as alternative prey became available. Given the high rates of pneumonia-caused mortality we observed, and the apparent lack of pneumonia-causing pathogens in bighorn populations in the western Black Hills, management activities should be geared towards eliminating contact between diseased and healthy populations.
Rights
This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.
Language
en
File Format
application/pdf
Recommended Citation
Smith, Joshua B.; Jenks, Jonathan A.; Grovenburg, Troy W.; and Klaver, Robert W., "Disease and Predation: Sorting out Causes of a Bighorn Sheep (Ovis canadensis) Decline" (2014). Natural Resource Ecology and Management Publications. 229.
https://lib.dr.iastate.edu/nrem_pubs/229
Included in
Natural Resources and Conservation Commons, Natural Resources Management and Policy Commons, Population Biology Commons, Sheep and Goat Science Commons, Terrestrial and Aquatic Ecology Commons
Comments
This article is published as Smith JB, Jenks JA, Grovenburg TW, Klaver RW (2014) Disease and Predation: Sorting out Causes of a Bighorn Sheep (Ovis canadensis) Decline. PLoS ONE 9(2): e88271. doi: 10.1371/journal.pone.0088271.