How do trees respond to species mixing in experimental compared to observational studies?

• Main Authors: Stephan Kambach, Eric Allan, Simon Bilodeau‐Gauthier, David A. Coomes, Josephine Haase, Tommaso Jucker, Georges Kunstler, Sandra Müller, Charles Nock, Alain Paquette, Fons van derPlas, Sophia Ratcliffe, Fabian Roger, Paloma Ruiz‐Benito, Michael Scherer‐Lorenzen, Harald Auge, Olivier Bouriaud, Bastien Castagneyrol, Jonas Dahlgren, Lars Gamfeldt, Hervé Jactel, Gerald Kändler, Julia Koricheva, Aleksi Lehtonen, Bart Muys, Quentin Ponette, Nuri Setiawan, Thomas Van de Peer, Kris Verheyen, Miguel A. Zavala, Helge Bruelheide
• Format: Article
• Language: English
• Published: Wiley 2019-10-01
• Series: Ecology and Evolution
• Subjects: biodiversity; ecosystem function and services; FunDivEUROPE; national forest inventories; productivity; species richness
• Online Access: https://doi.org/10.1002/ece3.5627

Abstract For decades, ecologists have investigated the effects of tree species diversity on tree productivity at different scales and with different approaches ranging from observational to experimental study designs. Using data from five European national forest inventories (16,773 plots), six tree species diversity experiments (584 plots), and six networks of comparative plots (169 plots), we tested whether tree species growth responses to species mixing are consistent and therefore transferrable between those different research approaches. Our results confirm the general positive effect of tree species mixing on species growth (16% on average) but we found no consistency in species‐specific responses to mixing between any of the three approaches, even after restricting comparisons to only those plots that shared similar mixtures compositions and forest types. These findings highlight the necessity to consider results from different research approaches when selecting species mixtures that should maximize positive forest biodiversity and functioning relationships.