Stability of Degree Heterogeneous Ecological Networks

TL;DR

This paper investigates how degree heterogeneity influences ecological network stability, revealing that its effects vary with interaction types and prey contiguity, providing insights into the stability of complex ecological systems.

Contribution

It systematically analyzes the role of degree heterogeneity in ecological stability across different interaction types, a property previously underexplored.

Findings

Degree heterogeneity destabilizes networks with competitive and mutualistic interactions.

In predator-prey networks, increased heterogeneity stabilizes food webs with low prey contiguity.

High prey contiguity diminishes the stabilizing effect of heterogeneity in food webs.

Abstract

A classic measure of ecological stability describes the tendency of a community to return to equilibrium after small perturbation. While many advances show how the network structure of these communities severely constrains such tendencies, few if any of these advances address one of the most fundamental properties of network structure: heterogeneity among nodes with different numbers of links. Here we systematically explore this property of "degree heterogeneity" and find that its effects on stability systematically vary with different types of interspecific interactions. Degree heterogeneity is always destabilizing in ecological networks with both competitive and mutualistic interactions while its effects on networks of predator-prey interactions such as food webs depend on prey contiguity, i.e., the extent to which the species consume an unbroken sequence of prey in community niche space. Increasing degree heterogeneity stabilizes food webs except those with the most contiguity. These findings help explain previously unexplained observations that food webs are highly but not completely contiguous and, more broadly, deepens our understanding of the stability of complex ecological networks with important implications for other types of dynamical systems.