Stabilizing spatially structured populations through Adaptive Limiter Control

TL;DR

This paper demonstrates that Adaptive Limiter Control (ALC) effectively stabilizes complex biological populations and metapopulations, reducing fluctuations and extinction risk even under noisy, high-extinction conditions, without needing detailed system parameters.

Contribution

The study provides a detailed numerical analysis showing ALC's robustness and effectiveness in stabilizing populations with minimal information and under challenging conditions.

Findings

ALC stabilizes populations at high migration rates without prior growth rate knowledge.

ALC reduces fluctuations and extinction probability in metapopulations.

Effective even with high extinction rates and moderate environmental noise.

Abstract

Stabilizing the dynamics of complex, non-linear systems is a major concern across several scientific disciplines including ecology and conservation biology. Unfortunately, most methods proposed to reduce the fluctuations in chaotic systems are not applicable for real, biological populations. This is because such methods typically require detailed knowledge of system specific parameters and the ability to manipulate them in real time; conditions often not met by most real populations. Moreover, real populations are often noisy and extinction-prone, which can sometimes render such methods ineffective. Here we investigate a control strategy, which works by perturbing the population size, and is robust to reasonable amounts of noise and extinction probability. This strategy, called the Adaptive Limiter Control (ALC), has been previously shown to increase constancy and persistence of laboratory populations and metapopulations of Drosophila melanogaster. Here we present a detailed numerical investigation of the effects of ALC on the fluctuations and persistence of metapopulations. We show that at high migration rates, application of ALC does not require a priori information about the population growth rates. We also show that ALC can stabilize metapopulations even when applied to as low as one-tenth of the total number of subpopulations. Moreover, ALC is effective even when the subpopulations have high extinction rates: conditions under which one other control algorithm has previously failed to attain stability. Importantly, ALC not only reduces the fluctuation in metapopulation sizes, but also the global extinction probability. Finally, the method is robust to moderate levels of noise in the dynamics and the carrying capacity of the environment. These results, coupled with our earlier empirical findings, establish ALC to be a strong candidate for stabilizing real biological metapopulations.