Bifurcations, Multistability, and Chaos in a Stochastic Age-Structured Population Model with the Allee Effect

The problem of analyzing complex stochastic dynamics of multi-age population systems with the Allee effect is investigated. In this study, a discrete Ricker-type model of interacting juvenile and adult subpopulations is used. Bifurcation analysis of the original deterministic model is carried out depending on the strength of the Allee effect. A parametric description of multistability zones, regular and chaotic attractors, and their basins is given. Mechanisms of noise-induced extinction and stochastic transitions between order and chaos are identified in mono- and bi-rhythmicity parameter regions. The important role of chaotic transient processes in the generation of chaos by noise in order zones is revealed. In this analysis, constructive capabilities of the analytical method of confidence ellipses are demonstrated.