Spatial population dynamics: Beyond the Kirkwood superposition approximation by advancing to the Fisher–Kopeliovich ansatz

Abstract

The superior Fisher–Kopeliovich closure is applied to the hierarchy of master equations for spatial moments in population dynamics for the first time. As a consequence, the density, pair and triplet distribution functions of entities are calculated within this closure for a birth–death model with nonlocal dispersal and competition in continuous space. The new results are compared with those obtained by “exact” individual-based simulations as well as by the inferior mean-field and Kirkwood superposition approximations. It is shown that the Fisher–Kopeliovich approach significantly improves the quality of the description in a wide range of varying parameters of the model.