Ternary network models for disturbed ecosystems.

Area of Science:

• Ecology
• Mathematical Biology
• Theoretical Ecology

Background:

• Ecosystem responses to disturbances are complex due to intricate species interactions.
• Current models often simplify species to binary presence-absence, limiting representable behaviors.
• This simplification hinders understanding of complex ecological dynamics and disturbance impacts.

Purpose of the Study:

• To develop and apply discrete population models that extend beyond binary species descriptions.
• To introduce ternary (three-state) models incorporating presence, absence, and overabundance.
• To analyze ecosystem robustness and model novel disturbance types using this expanded framework.

Main Methods:

• Development of discrete ternary population models.
• Application of the ternary framework to ecosystem robustness analysis.
• Comparison of ternary model results with traditional binary models.

Main Results:

• Ternary models enable the simulation of top-down extinction cascades from consumer pressure or mesopredator release.
• These effects are not captured by standard binary models.
• The ternary approach allows modeling of disturbances involving externally induced species overabundance.

Conclusions:

• Ternary population models offer a richer description of ecosystem dynamics and disturbances.
• This expanded framework preserves conceptual simplicity while enhancing ecological realism.
• The method provides new insights into ecosystem resilience and vulnerability to various pressures.