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Environmental versus demographic variability in two-species predator-prey models
Ulrich Dobramysl1, Uwe C Täuber1
1Department of Physics, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0435, USA.
Physical Review Letters
|August 29, 2014
Summary
Environmental variability boosts predator and prey populations in Lotka-Volterra models, while demographic variability leads to neutral optimization. These findings highlight the distinct impacts of noise on ecological dynamics.
Area of Science:
- Ecology
- Evolutionary Biology
- Theoretical Biology
Background:
- Ecological models like the Lotka-Volterra system are fundamental to understanding species interactions.
- Stochasticity, encompassing both demographic and environmental factors, plays a crucial role in shaping population dynamics.
- Distinguishing the effects of different noise sources is essential for accurate ecological predictions.
Purpose of the Study:
- To investigate the competing effects of demographic and environmental variability.
- To determine the relative importance of these variability types on evolutionary dynamics.
- To analyze a stochastic two-species Lotka-Volterra model with spatial structure.
Main Methods:
- Utilized Monte Carlo simulations on a two-dimensional lattice.
- Incorporated inheritable predation efficiencies for individuals.
- Modeled environmental noise through quenched randomness in spatially varying reaction rates.
Main Results:
- Environmental variability was found to enhance population densities for both predator and prey species.
- Demographic variability resulted in a phenomenon akin to neutral optimization.
- The spatial structure and inheritable traits influenced the dynamics under different noise regimes.
Conclusions:
- Environmental noise can be a significant driver of population growth and stability.
- Demographic stochasticity may lead to less directed evolutionary trajectories.
- The interplay between intrinsic and extrinsic factors critically shapes ecological and evolutionary outcomes.
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