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Parasite-Mediated Competition Limits Dominant Cervid Competitor
Jennifer A Grauer1, Joshua P Twining2, Manigandan Lejeune3
1New York Cooperative Fish and Wildlife Research Unit, Department of Natural Resources and the Environment, Cornell University, Ithaca, New York, USA.
Ecology Letters
|June 25, 2025
Summary
Parasites critically impact wildlife communities. This study found parasite-mediated competition, not direct competition, limits moose (Alces alces) populations, highlighting indirect interactions
Area of Science:
- Ecology
- Wildlife Conservation
- Parasitology
Background:
- Species interactions shape ecological communities through direct and indirect pathways.
- Empirical evidence for the importance of indirect interactions, particularly parasite-mediated competition, is limited.
- Understanding these interactions is crucial for managing wildlife populations and biodiversity.
Purpose of the Study:
- To investigate the role of parasite-mediated competition in structuring interactions between moose (Alces alces) and white-tailed deer (Odocoileus virginianus).
- To determine if direct or indirect interactions limit moose occupancy in a shared habitat.
- To provide empirical evidence for the significance of indirect interactions in community ecology.
Main Methods:
- Utilized 2 years of detection/non-detection data for moose and white-tailed deer.
- Analyzed parasite loads in fecal samples (Parelaphostrongylus tenuis, Fascioloides magna).
- Employed a hierarchical abundance-mediated interaction model to assess interspecific competition.
Main Results:
- Moose occupancy was significantly limited by parasite-mediated competition.
- No evidence of population-level effects from direct competitive interactions between moose and white-tailed deer was found.
- Parasites play a critical role in shaping cervid community structure.
Conclusions:
- Indirect interactions, specifically parasite-mediated competition, are a key driver of community outcomes.
- Conservation and management strategies must consider the impact of parasites on species interactions.
- Findings are vital for addressing challenges like habitat loss, disease, and climate change affecting wildlife.
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