title: No complexity-stability relationship in empirical ecosystems.
abstract: Understanding the mechanisms responsible for stability and persistence of ecosystems is one of the greatest challenges in ecology. Robert May showed that, contrary to intuition, complex randomly built ecosystems are less likely to be stable than simpler ones. Few attempts have been tried to test May's prediction empirically, and we still ignore what is the actual complexity-stability relationship in natural ecosystems. Here we perform a stability analysis of 116 quantitative food webs sampled worldwide. We find that classic descriptors of complexity (species richness, connectance and interaction strength) are not associated with stability in empirical food webs. Further analysis reveals that a correlation between the effects of predators on prey and those of prey on predators, combined with a high frequency of weak interactions, stabilize food web dynamics relative to the random expectation. We conclude that empirical food webs have several non-random properties contributing to the absence of a complexity-stability relationship.
authors.affiliation: Département de Biologie, Université du Québec à Rimouski, 300 Allée des Ursulines, Quebec, Canada G5L 3A1.|Quebec Center for Biodiversity Science, Montréal, Quebec, Canada H3A 1B1.|UMR MARBEC, Université de Montpellier, Place Eugène Bataillon, F-34095 Montpellier cedex 05, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Jacquet
authors.affiliation: Institut des Sciences de la Mer de Rimouski, Université du Québec à Rimouski, 310 Allée des Ursulines, Quebec, Canada G5L 3A1.|Centre de Recherches Insulaires et Observatoire de l'Environnement, EPHE, PSL Research University, UPVD, CNRS, USR 3278 CRIOBE, F-98729 Moorea, French Polynesia.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Moritz
authors.affiliation: M-Expertise Marine, 10 rue Luce-Drapeau, Sainte-Luce Quebec, Canada G0K1P0.
authors.forename: Lyne
authors.initials: L
authors.lastname: Morissette
authors.affiliation: Département de Biologie, Université du Québec à Rimouski, 300 Allée des Ursulines, Quebec, Canada G5L 3A1.|Quebec Center for Biodiversity Science, Montréal, Quebec, Canada H3A 1B1.
authors.forename: Pierre
authors.initials: P
authors.lastname: Legagneux
authors.affiliation: Unité Evolution, Ecologie &Paléontologie (EEP), SPICI group, CNRS UMR 8198, Université Lille 1, Bâtiment SN2, F-59655 Villeneuve d'Ascq cedex, France.
authors.forename: François
authors.initials: F
authors.lastname: Massol
authors.affiliation: Institut des Sciences de la Mer de Rimouski, Université du Québec à Rimouski, 310 Allée des Ursulines, Quebec, Canada G5L 3A1.|Québec-Océan, Département de biologie, Université Laval, Pavillon Alexandre Vachon, 1045, avenue de la médecine, Quebec, QC, Canada G1V 0A6.
authors.forename: Philippe
authors.initials: P
authors.lastname: Archambault
authors.affiliation: Département de Biologie, Université du Québec à Rimouski, 300 Allée des Ursulines, Quebec, Canada G5L 3A1.|Quebec Center for Biodiversity Science, Montréal, Quebec, Canada H3A 1B1.|Département de biologie, Faculté des Sciences, Université de Sherbrooke, 2500 Boulevard Université, Sherbrooke, Quebec, Canada J1K 2R1.
authors.forename: Dominique
authors.initials: D
authors.lastname: Gravel