Emergence of structural patterns in neutral trophic networks

PLoS One. 2012;7(8):e38295. doi: 10.1371/journal.pone.0038295. Epub 2012 Aug 10.

Abstract

Interaction networks are central elements of ecological systems and have very complex structures. Historically, much effort has focused on niche-mediated processes to explain these structures, while an emerging consensus posits that both niche and neutral mechanisms simultaneously shape many features of ecological communities. However, the study of interaction networks still lacks a comprehensive neutral theory. Here we present a neutral model of predator-prey interactions and analyze the structural characteristics of the simulated networks. We find that connectance values (complexity) and complexity-diversity relationships of neutral networks are close to those observed in empirical bipartite networks. High nestedness and low modularity values observed in neutral networks fall in the range of those from empirical antagonist bipartite networks. Our results suggest that, as an alternative to niche-mediated processes that induce incompatibility between species ("niche forbidden links"), neutral processes create "neutral forbidden links" due to uneven species abundance distributions and the low probability of interaction between rare species. Neutral trophic networks must be seen as the missing endpoint of a continuum from niche to purely stochastic approaches of community organization.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biodiversity
  • Computer Simulation
  • Ecosystem*
  • Food Chain*
  • Models, Theoretical*
  • Population Dynamics

Grants and funding

Dr. Canard was supported by a MENRT grant from Ministry of Higher Education and Research of France. Dr. Mouquet was supported by the CNRS. Dr. Gravel was supported by NSERC and the Canada Research Chair program. Dr. Marescot was supported by a grant from the French National Game and Wildlife Agency (Office National de la Chasse et de la Faune Sauvage). Dr. Gaston was supported by the European Research Council under the European Union's Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement no. 268504. Dr. Mouillot was supported by Marie Curie International Outgoing Fellowship (FISHECO) IOF-GA-2009-236316. This study was partially funded by the FRB project BIODIVMED and by the ANR project BIODIVNEK. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.