High-order interactions maintain or enhance structural robustness of a coffee agroecosystem network

Abstract

The capacity of highly diverse systems to prevail has proven difficult to explain. In addition to methodological issues, the inherent complexity of ecosystems and issues like multicausality, non-linearity and context-specificity make it hard to establish general and unidirectional explanations. Nevertheless, in recent years, high order interactions have been increasingly discussed as a mechanism that benefits the functioning of highly diverse ecosystems and may add to the mechanisms that explain their persistence. Until now, this idea has been explored by means of hypothetical simulated networks. Here, we test this idea using an updated and empirically documented network for a coffee agroecosystem. We identify potentially key nodes and measure network robustness in the face of node removal with and without incorporation of high order interactions. We find that the system's robustness is either increased or unaffected by the addition of high order interactions, in contrast with randomized counterparts with similar structural characteristics. We also propose a method for representing networks with high order interactions as ordinary graphs and a method for measuring their robustness.

Surprising effects of cascading higher order interactions

“…Reviews and empirical studies suggest that, by initiating the phenotypic response of a resource or a competitor, a modification species can cause strong effects on a pairwise interaction, consequently leading to strong effects at population, community, and ecosystem levels [5,7,35]. Theoretical and empirical studies found that HOIs increase the robustness of food webs [4,[11][12][13], and the structure of two interactive HOIs can stabilize biodiversity-rich ecological networks [11]. With such a recognition, however, most theoretical and empirical…”

“…interaction modification, in contrast to interaction chain, [2]), has been widely recognized in ecological studies [3][4][5][6][7][8][9][10]. Yet, studies remain in theoretical explorations of large communities focusing on diversity and stability [4,[11][12][13], or consumption coefficients in small or large ecological communities with only one degree HOIs (i.e. one additional species modifying one pair-wise interaction) [5,7,8,10,14,15].…”