Can a More Variable Species Win Interspecific Competition?

Area of Science:

• Ecology
• Population Dynamics
• Mathematical Biology

Background:

• Population dynamics are influenced by individual variability in resource assimilation.
• Resource partitioning and individual growth rates affect population persistence.
• Understanding inter-species competition requires modeling individual differences.

Purpose of the Study:

• To investigate the impact of individual variability on population dynamics and extinction times.
• To compare two models of individual variability: symmetric and asymmetric resource distribution.
• To analyze the outcomes of inter-species competition under varying levels of individual variability.

Main Methods:

• Developed individual-based models with symmetric (normal distribution of assimilation) and asymmetric (resource-dependent future acquisition) resource partitioning.
• Simulated population dynamics and extinction times under different variability scenarios.
• Examined inter-species competition dynamics using common resources.

Main Results:

• Increased individual variability significantly extends population extinction time compared to identical individuals.
• Interspecies competition: more variable species tend to exclude less variable ones, especially with large differences.
• Coexistence is possible with equal or slightly different variabilities, particularly when both species are highly variable.

Conclusions:

• Individual variability is a crucial factor in population persistence and competitive exclusion.
• The nature of resource distribution (symmetric vs. asymmetric) influences the deterministic or statistical nature of outcomes.
• The specific mechanism of variability introduction (e.g., proportion of low-resource individuals) can alter competitive dynamics and extinction probabilities.