Non-trophic interactions strengthen the diversity-functioning relationship in an ecological bioenergetic network model.

Vincent Miele,Rodrigo Ramos-Jiliberto,Christian Guill,Sonia Kéfi,Jacopo Grilli

doi:10.1371/journal.pcbi.1007269

Abstract

Ecological communities are undeniably diverse, both in terms of the species that compose them as well as the type of interactions that link species to each other. Despite this long recognition of the coexistence of multiple interaction types in nature, little is known about the consequences of this diversity for community functioning. In the ongoing context of global change and increasing species extinction rates, it seems crucial to improve our understanding of the drivers of the relationship between species diversity and ecosystem functioning. Here, using a multispecies dynamical model of ecological communities including various interaction types (e.g. competition for space, predator interference, recruitment facilitation in addition to feeding), we studied the role of the presence and the intensity of these interactions for species diversity, community functioning (biomass and production) and the relationship between diversity and functioning.Taken jointly, the diverse interactions have significant effects on species diversity, whose amplitude and sign depend on the type of interactions involved and their relative abundance. They however consistently increase the slope of the relationship between diversity and functioning, suggesting that species losses might have stronger effects on community functioning than expected when ignoring the diversity of interaction types and focusing on feeding interactions only.

Highlights

Despite the wide recognition of the coexistence of multiple interaction types linking species in nature [1,2,3], research on ecological networks has been massively dominated by studies on a single interaction at a time
Using a multispecies dynamical model of ecological communities including various interaction types, we studied the role of the presence and the intensity of these interactions for species diversity, community functioning and the relationship between diversity and functioning.Taken jointly, the diverse interactions have significant effects on species diversity, whose amplitude and sign depend on the type of interactions involved and their relative abundance
The question of how species diversity contributes to the functioning of ecological communities has intrigued ecologists for decades, and is especially relevant in the current context of species extinctions

Summary

Introduction

Despite the wide recognition of the coexistence of multiple interaction types linking species in nature [1,2,3], research on ecological networks has been massively dominated by studies on a single interaction at a time (e.g. trophic, competitive or mutualistic; e.g. [4,5,6]). Despite the wide recognition of the coexistence of multiple interaction types linking species in nature [1,2,3], research on ecological networks has been massively dominated by studies on a single interaction at a time Goudard and Loreau [18] investigated the effect of rheagogies on the relationship between biodiversity and ecosystem functioning (BEF) in a tri-trophic model. They showed that ecosystem biomass and production depended on species richness and on the connectance and magnitude of the non-trophic interactions

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