Route to chaos in multi-species ecosystems

Area of Science:

• Ecology
• Mathematical Biology
• Dynamical Systems Theory

Background:

• Ecosystem models often focus on equilibrium states.
• Persistent dynamics, including limit cycles and chaos, are observed in real and modeled ecosystems.
• Understanding the drivers of complex ecosystem dynamics is crucial.

Purpose of the Study:

• To investigate species-rich mathematical models of ecosystems.
• To explore the emergence of limit cycles and chaotic dynamics from interspecies interaction variability.
• To unify diverse population dynamics within a single model framework.

Main Methods:

• Analysis of species-rich mathematical ecosystem models.
• Investigation of Hopf bifurcations and parameter tuning.
• Application of random matrix theory arguments.
• Numerical simulations to observe population dynamics.

Main Results:

• Increasing interaction variability drives limit cycles and strange attractors.
• Chaotic dynamics (positive Lyapunov exponent) emerge with increased variability.
• Limit cycles and strange attractors can maintain biodiversity by preventing species extinction.
• This route to chaos is prevalent in predator-prey dominated systems.

Conclusions:

• A unifying model framework explains diverse population dynamics.
• Interspecies interaction variability is a key driver of complex ecosystem dynamics.
• The findings suggest a generic scenario for chaos in large, species-rich ecosystems.