The effects of stochastic population dynamics on food web structure

TL;DR

This paper introduces a stochastic individual-based model for food web simulation that aligns with existing models in large populations but reveals significant effects of demographic fluctuations in small populations.

Contribution

It presents a novel stochastic model that extends the Webworld framework to account for demographic fluctuations in small populations.

Findings

Demographic fluctuations significantly affect small populations in food webs.

The stochastic model closely matches deterministic Webworld results in large populations.

Small-population species exhibit systematic differences due to stochastic effects.

Abstract

We develop a stochastic, individual-based model for food web simulation which in the large-population limit reduces to the well-studied Webworld model, which has been used to successfully construct model food webs with several realistic features. We demonstrate that an almost exact match is found between the population dynamics in fixed food webs, and that the demographic fluctuations have systematic effects when the new model is used to construct food webs due to the presence of species with small populations.