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.