Endogenous ecological memory (EEM) refers to the phenomenon where past states of a system (i.e. population density) can influence present states. Dormancy is an example of EEM. In this paper, we address the effects of EEM on qualitative changes in population dynamics over-time. The goal was to determine the effects of EEM on the resilience of a population. We analyze the discrete-time Ricker model St+1 = RStexp(r(1-St/K)) with environmental stochasticity. We explore the model when time-delays are restricted to the density-dependent (exp(r(1-St/K))) component of the model and log-normal multiplicative noise is incorporated as well. Simulation results show that population resilience, as measured by the standard deviation of population density about the carrying capacity, decreases as the duration of EEM increases. Moreover, resilience decreases with increasing fecundity R, which differs from the predictions of some other theoretical and empirical work. We observe boom-bust cycles in population density for significantly long time-delays in density dependence. These cycles become more extreme as the regulating effects of density-dependence are increasingly delayed.
