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Food-web models that generate constant predator-prey ratios
1Department of Biology, University of York, Y01 5DD, Heslington, York, UK.
Oecologia
|March 18, 2017
Summary
Apparent competition, where prey species share predators, may explain the consistent predator-to-prey species ratios observed in nature. This ecological mechanism helps stabilize food webs, even with varied initial conditions and species biology.
Area of Science:
- Ecology
- Theoretical Ecology
- Community Ecology
Background:
- Natural communities often exhibit a stable ratio of predator to prey species.
- The ecological factors driving this consistent ratio are not fully understood.
Purpose of the Study:
- To test the hypothesis that apparent competition generates constant predator/prey ratios.
- To investigate the role of competition for enemy-free space in community stability.
Main Methods:
- Simulated simple, two-trophic-level communities using Lotka-Volterra models.
- Drew predator and prey species randomly from a species pool.
- Simulated invasion and extinction dynamics over time.
Main Results:
- Simulated food webs converged to stable states with consistent predator/prey ratios.
- The exact ratio varied based on species' biological traits.
- Initial conditions did not prevent convergence to stable ratios.
Conclusions:
- Apparent competition among prey via shared predators is a plausible mechanism for generating stable predator/prey ratios.
- This mechanism contributes to the stability of ecological communities.
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