We study the evolution in discrete time of certain age-structuredpopulations, such as adults and juveniles, with a Ricker fitness function. Wedetermine conditions for the convergence of orbits to the origin (extinction)in the presence of the Allee effect and time-dependent vital rates. We showthat when stages interact, they may survive in the absence of interior fixedpoints, a surprising situation that is impossible without inter-stageinteractions. We also examine the shift in the interior Allee equilibriumcaused by the occurrence of interactions between stages and find that theextinction or Allee threshold does not extend to the new boundaries set by theshift in equilibrium, i.e. no interior equilibria are on the extinctionthreshold.
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