title: Functional identity is the main driver of diversity effects in young tree communities.
abstract: Two main effects are proposed to explain biodiversity-ecosystem functioning relationships: niche complementarity and selection effects. Both can be functionally defined using the functional diversity (FD) and functional identity (FI) of the community respectively. Herein, we present results from the first tree diversity experiment that separated the effect of selection from that of complementarity by varying community composition in high-density plots along a gradient of FD, independent of species richness and testing for the effects of FD and community weighted means of traits (a proxy for FI) on stem biomass increment (a proxy for productivity). After 4 years of growth, most mixtures did not differ in productivity from the averages of their respective monocultures, but some did overyield significantly. Those positive diversity effects resulted mostly from selection effects, primarily driven by fast-growing deciduous species and associated traits. Net diversity effect did not increase with time over 4 years.
authors.affiliation: Center for Forest Research, Université du Québec à Montréal, PO Box 8888, Centre-ville Station, Montréal, QC, H3C 3P8, Canada.
authors.forename: Cornelia M
authors.initials: CM
authors.lastname: Tobner
authors.affiliation: Center for Forest Research, Université du Québec à Montréal, PO Box 8888, Centre-ville Station, Montréal, QC, H3C 3P8, Canada.
authors.forename: Alain
authors.initials: A
authors.lastname: Paquette
authors.affiliation: Université de Sherbrooke, 2500 Boulevard de l'Université, Sherbrooke, QC, J1K 2R1, Canada.|Québec Center for Biodiversity Science, McGill University, 1205 Dr. Penfield Avenue, Montréal, Québec, Canada H3A 1B1.
authors.forename: Dominique
authors.initials: D
authors.lastname: Gravel
authors.affiliation: Department of Forest Resources, University of Minnesota, St. Paul, MN, 55108, USA.|Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, 2753, Australia.
authors.forename: Peter B
authors.initials: PB
authors.lastname: Reich
authors.affiliation: Department of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, MN, 55108, USA.
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Williams
authors.affiliation: Center for Forest Research, Université du Québec à Montréal, PO Box 8888, Centre-ville Station, Montréal, QC, H3C 3P8, Canada.|Institut des sciences de la forêt tempérée (ISFORT), Université du Québec en Outaouais (UQO), 58 rue Principale, Ripon, QC, J0V 1V0, Canada.
authors.forename: Christian
authors.initials: C
authors.lastname: Messier
mesh_terms: D044822:Biodiversity; D018533:Biomass; D004463:Ecology / Q000379:methods*; D008954:Models, Biological; D011792:Quebec; D014197:Trees / Q000145:classification* / Q000254:growth & development
keywords: Biodiversity and ecosystem functioning; IDENT; biodiversity experiment; complementarity; functional diversity; functional identity; functional traits of trees; overyielding