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Sympatry Increases Predation Risk for an Endangered Ungulate
Daniel Gordon1, Rebecca L Lewison1, Randy Botta2
1Department of Biology San Diego State University San Diego California USA.
Ecology and Evolution
|August 9, 2026
Summary
Predation risk for endangered Peninsular bighorn sheep increases with abundant mule deer presence. Understanding sympatric species abundance is crucial for accurate risk assessments and recovery efforts.
Area of Science:
- Ecology
- Wildlife Conservation
- Population Dynamics
Background:
- Predation risk for low-abundance prey is influenced by their own numbers and the abundance of sympatric species.
- The interaction between Peninsular bighorn sheep (Ovis canadensis nelsoni) and southern mule deer (Odocoileus hemionus fuliginatus) in Southern California is poorly understood regarding puma (Puma concolor) predation risk.
Purpose of the Study:
- To investigate how the abundance and habitat suitability of southern mule deer affect predation risk for Peninsular bighorn sheep.
- To develop more accurate predation risk models for endangered ungulate populations.
Main Methods:
- Characterized puma predation risk for bighorn sheep and mule deer across their ranges.
- Analyzed the influence of topography, habitat, forage, and prey habitat suitability on puma kill sites.
- Assessed the impact of mule deer abundance and habitat suitability on bighorn sheep predation risk.
Main Results:
- The presence of mule deer increased predation risk for both bighorn sheep and mule deer.
- Predation risk for bighorn sheep significantly increased with higher mule deer habitat suitability.
- Spatial overlap between low-density bighorn sheep and high-density mule deer amplifies predation risk for bighorn sheep.
Conclusions:
- Sympatric species abundance, particularly abundant prey species, significantly impacts predation risk for lower-density populations.
- Incorporating sympatric species density into population models and management plans is essential for effective conservation of endangered species like Peninsular bighorn sheep.
- Findings provide critical data for Peninsular bighorn sheep recovery efforts.
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