Advent of Extreme Events in Predator Populations

TL;DR

This paper investigates how coupled predator-prey systems can spontaneously generate extreme predator population events, revealing the role of coupling strength in the emergence of rare, large deviations in population dynamics.

Contribution

It demonstrates that coupling interactions in predator-prey models can lead to extreme events, a phenomenon not previously characterized in such systems.

Findings

Predator populations exhibit rare, explosive bursts in isolated patches.

Maximum predator biomass increases with coupling strength.

Extreme value distributions fit well, showing increased location and scale with coupling.

Abstract

We study the dynamics of a ring of patches with vegetation-prey-predator populations, coupled through interactions of the Lotka-Volterra type. We find that the system yields aperiodic, recurrent and rare explosive bursts of predator density in a few isolated spatial patches from time to time. Further, the collective predator biomass also exhibits sudden uncorrelated occurrences of large deviations as the coupled system evolves. The maximum value of the predator population in a patch, as well as the maximum value of the predator biomass, increases with coupling strength. These trends are further corroborated by fits to Generalized Extreme Value distributions, where the location and scale factor of the distribution increases markedly with coupling strength, indicating the crucial role of coupling interactions in the generation of extreme events. These results indicate how occurrences of extremely large predator populations can emerge in coupled population dynamics, and in a more general context they suggest a generic class of deterministic nonlinear systems that can naturally exhibit extreme events.