Stochastic Dispersal and Population Persistence in Marine Organisms

Temporally variable conditions introduce time dependence into vital rates, and predicting the effect of this variability on population dynamics and persistence is critical for the effective management of natural populations subject to fluctuating environments. In many marine species, dispersal during the larval stage establishes links among populations and is largely determined by temporally variable fluid dynamic processes. However, the consequences of time-dependent dispersal for population persistence are largely unexplored, and so we present a model of stochastically driven dispersal to study population persistence in a temporally variable, patchy habitat. We illustrate how patterns of temporal autocorrelation, expressed as variance in stochastic population connectivity, can have counter-intuitive consequences for predictions, where switching between two sets of dynamics, each of which leads to extinction, can promote metapopulation persistence. We contend that accounting for stochastic dispersal can have great relevance for understanding population persistence, in marine populations in particular and in organisms with some degree of passive dispersal in general.