Ecological Networks over the Edge: Hypergraph Trait-Mediated Indirect Interaction (TMII) Structure

Abstract

Analyses of ecological network structure have yielded important insights into the functioning of complex ecological systems. However, such analyses almost universally omit non-pairwise interactions, many classes of which are crucial for system structure, function, and resilience. Hypergraphs are mathematical constructs capable of considering such interactions: we discuss their utility for studying ecological networks containing diverse interaction types, and associated challenges and strategies. We demonstrate the approach using a real-world coffee agroecosystem in which resistance to agricultural pests depends upon a large number of TMIIs. A hypergraph representation successfully reflects both the importance of species imposing such effects and the context-dependency of that importance in terms of how it is affected by removal of other species from the system.

Keywords: ecological network; food web; hypergraph; interaction modification; nontrophic interaction; trait-mediated indirect interaction.