Non-Markovian stochasticity in planktonic predator-prey populations

Abstract

Temporal persistence in a predator-prey system has been attributed to an observed stochasticity in the population of two or more species. Using a stochastic model with memory, we mathematically characterize the fluctuations in a coupled cyclic population in experiments involving Brachionus calyciflorus rotifers and their green algae prey. The probability density function (PDF) of the stochastic process has a memory parameter µ and a characteristic frequency ν whose values are determined from the dataset. Specifically, we evaluate the mean square deviation (MSD) of the fluctuating populations of rotifers and green algae and match these with the theoretical MSD. The theoretical PDF is also compared with the probability displacement distribution of the populations.