Functional identity is the main driver of diversity effects in young tree communities

• Published in: Ecology letters Vol. 19; no. 6; pp. 638 - 647
• Main Authors: Tobner, Cornelia M., Paquette, Alain, Gravel, Dominique, Reich, Peter B., Williams, Laura J., Messier, Christian
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Ltd 01.06.2016; Blackwell Publishing Ltd
• Subjects: Biodiversity; Biodiversity and ecosystem functioning; biodiversity experiment; Biomass; Community composition; Complementarity; Composition effects; Ecology - methods; Ecosystems; functional diversity; functional identity; functional traits of trees; IDENT; Models, Biological; Monoculture; overyielding; Plant ecology; Productivity; Quebec; Species diversity; Species richness; Trees; Trees - classification; Trees - growth & development; functional diversity; overyielding; IDENT; biodiversity experiment; complementarity; Biodiversity and ecosystem functioning; functional identity; functional traits of trees
• ISSN: 1461-023X; 1461-0248
• DOI: 10.1111/ele.12600

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.