Resonant activation of population extinctions

Area of Science:

• Ecology and evolutionary biology
• Population dynamics modeling

Background:

• Population extinction is a critical issue in ecology and evolution.
• Stochastic factors significantly influence extinction, but interactions between demographic stochasticity and environmental noise are unclear.

Purpose of the Study:

• To investigate the impact of environmental noise on population extinction dynamics.
• To understand the interplay between demographic stochasticity and fluctuating environmental conditions.

Main Methods:

• Modeled environmental forcing as a two-state stochastic fluctuation with differing death rates.
• Analyzed the mean time to extinction under various fluctuation rates.
• Developed a heuristic description and criterion for resonant activation.

Main Results:

• Identified a specific rate of environmental fluctuations that minimizes the mean time to extinction.
• This phenomenon, termed resonant activation, occurs when the severity of rare events is balanced by their frequency.
• Established a criterion for the existence of resonant activation.

Conclusions:

• Environmental noise can exhibit complex effects on population persistence, including potentially slowing extinction.
• The findings offer insights into population viability under fluctuating environments and have implications for evolutionary models.
• The concept of resonant activation provides a framework for understanding extinction dynamics influenced by environmental stochasticity.