A discrete/continuous time resource competition model and its implications

Area of Science:

• Ecology
• Mathematical Biology
• Population Dynamics

Background:

• Ecological theory often predicts competitive exclusion between species vying for the same resources.
• Understanding factors influencing species coexistence is crucial for biodiversity and ecosystem stability.

Purpose of the Study:

• To investigate the dynamics of a two-consumer system competing for a continuously reproducing resource.
• To explore how differing annual birth pulse timings affect species coexistence and competitive outcomes.

Main Methods:

• Utilized a mixed time model to simulate consumer population dynamics.
• Analyzed system behavior at fixed points, considering consumer 'power' (time-averaged level).
• Investigated the impact of birth pulse timing and toxin exposure on competitive balance.

Main Results:

• Competitive exclusion is the general outcome, with the stronger competitor (higher 'power') typically winning.
• Instability in the stronger competitor's fixed point can allow weaker species invasion, leading to coexistence.
• Varying birth pulse times can result in diverse long-term behaviors, including cycles and chaos.
• Toxin pulse timing can alter the competitive balance between species.

Conclusions:

• Species coexistence is possible even with resource competition, particularly when fixed points are unstable or birth pulses are asynchronous.
• The timing of discrete events, like birth pulses or toxin exposure, significantly influences ecological dynamics and competitive outcomes.