title: Identity effects dominate the impacts of multiple species extinctions on the functioning of complex food webs.
abstract: Understanding the impacts of species extinctions on the functioning of food webs is a challenging task because of the complexity of ecological interactions. We report the impacts of experimental species extinctions on the functioning of two food webs of freshwater and marine systems. We used a linear model to partition the variance among the multiple components of the diversity effect (linear group richness, nonlinear group richness, and identity). The identity of each functional group was the best explaining variable of ecosystem functioning for both systems. We assessed the contribution of each functional group in multifunctional space and found that, although the effect of functional group varied across ecosystem functions, some functional groups shared common effects on functions. This study is the first experimental demonstration that functional identity dominates the effects of extinctions on ecosystem functioning, suggesting that generalizations are possible despite the inherent complexity of interactions.
authors.affiliation: Canada Research Chair in Continental Ecosystem Ecology, Université du Québec a Rimouski, Rimouski, Quebec G5L 3A1, Canada. eharve01@uoguelph.ca
authors.forename: Eric
authors.initials: E
authors.lastname: Harvey
authors.forename: Annie
authors.initials: A
authors.lastname: Séguin
authors.forename: Christian
authors.initials: C
authors.lastname: Nozais
authors.forename: Philippe
authors.initials: P
authors.lastname: Archambault
authors.forename: Dominique
authors.initials: D
authors.lastname: Gravel
mesh_terms: D000818:Animals; D044822:Biodiversity; D002170:Canada; D003247:Conservation of Natural Resources; D053476:Extinction, Biological; D020387:Food Chain; D005618:Fresh Water; D044645:Fucus / Q000502:physiology*; D007448:Invertebrates / Q000145:classification / Q000502:physiology*; D008954:Models, Biological; D009792:Oceans and Seas