Experimental evidence for nature's hidden network of higher-order interactions

Abstract

Transcending pairwise interactions in ecological networks remains a challenge. Higher-order interactions, the modulation of a pairwise interaction by a third species, have so far only been demonstrated in models or small isolated systems. Their ubiquity at a community level remains unknown. Using field experiments, we tested how multiple interactions within a network changed with species composition by reducing the densities of distinct species in a diverse arthropod community. We revealed an extensive hidden network of higher-order interactions modifying each other and the “visible” direct interactions. Most pairwise interactions were affected by the manipulation of a non-interacting taxonomic group. The pervasiveness of these interaction modifications challenges pairwise approaches to understanding interaction outcomes and could shift our thinking about the structure and resilience of ecological communities.