Resonance in Physiologically Structured Population Models

Area of Science:

• Ecology
• Population Dynamics
• Marine Biology

Background:

• Understanding how environmental variation influences population dynamics is a key ecological challenge.
• Transfer functions, using linearization theory, link environmental variation spectra to population abundance fluctuations.

Purpose of the Study:

• To derive and compute the transfer function for continuous-time, size-structured population models.
• To analyze the transfer function for a stony coral population model to identify dynamical patterns.

Main Methods:

• Developed a method to derive and compute transfer functions for size-structured populations.
• Applied the method to a size-structured model of stony corals with open recruitment.
• Analyzed the frequency spectrum of population abundance in relation to environmental variation.

Main Results:

• Identified a sharp, multi-decade resonance in coral population dynamics.
• The resonance is driven by space competition between established colonies and recruits.
• Resonant frequency is primarily determined by colony growth rate; oscillations are favored by weak density dependence.

Conclusions:

• Transfer functions are effective for analyzing dynamics in physiologically structured population models.
• Size-structured models can reveal significant resonant phenomena, like those observed in coral reefs.
• These findings suggest potential dynamical behaviors in marine invertebrates in less degraded ecosystems.