How Structured Is the Entangled Bank? The Surprisingly Simple Organization of Multiplex Ecological Networks Leads to Increased Persistence and Resilience.

Sonia Kéfi,Evie A Wieters,Sergio A Navarrete,Vincent Miele,Eric L Berlow,Daniel Simberloff

doi:10.1371/journal.pbio.1002527

Abstract

Species are linked to each other by a myriad of positive and negative interactions. This complex spectrum of interactions constitutes a network of links that mediates ecological communities’ response to perturbations, such as exploitation and climate change. In the last decades, there have been great advances in the study of intricate ecological networks. We have, nonetheless, lacked both the data and the tools to more rigorously understand the patterning of multiple interaction types between species (i.e., “multiplex networks”), as well as their consequences for community dynamics. Using network statistical modeling applied to a comprehensive ecological network, which includes trophic and diverse non-trophic links, we provide a first glimpse at what the full “entangled bank” of species looks like. The community exhibits clear multidimensional structure, which is taxonomically coherent and broadly predictable from species traits. Moreover, dynamic simulations suggest that this non-random patterning of how diverse non-trophic interactions map onto the food web could allow for higher species persistence and higher total biomass than expected by chance and tends to promote a higher robustness to extinctions.

Highlights

In his description of the “entangled bank” of species, Darwin illustrated the principle that species must manage complex interdependencies to successfully coexist in natural communities [1,2,3,4,5,6,7]
Species interact with each other in many different ways, including predation, competition, and facilitation, and this can be modelled as a network of multiple interaction types
We found that the interaction-specific links are significantly more frequent in the Chilean web than expected in the random counterparts (p-value < 10−4; Table 1)

Summary

Introduction

In his description of the “entangled bank” of species, Darwin illustrated the principle that species must manage complex interdependencies to successfully coexist in natural communities [1,2,3,4,5,6,7]. In this context, evolutionary constraints set a landscape of trade-offs over which species must solve their basic needs within the context of other species (e.g., competition for refuges among herbivores forced by the common need to avoid predators) and stringent environmental conditions. The analysis tools from network science are only recently addressing the “multiplex” nature of most natural networks, i.e., the fact that they include different interaction types between a given set of species (e.g., [8,9,10,11])

Methods

Results

Discussion

Conclusion