Diverse plant communities are often more productive than mono-specific ones. Several possible mechanisms underlie this phenomenon but their relative importance remains unknown. Here we investigated whether light interception alone or in combination with light use efficiency (LUE) of dominant and subordinate species explained greater productivity of mixtures relative to monocultures (i.e. overyielding) in 108 young experimental tree communities. We found mixed-species communities that intercepted more light than their corresponding monocultures had 84% probability of overyielding. Enhanced LUE, which arose via several pathways, also mattered: the probability of overyielding was 71% when, in a mixture, species with higher ‘inherent’ LUE (i.e. LUE in monoculture) intercepted more light than species with lower LUE; 94% when dominant species increased their LUE in mixture; and 79% when subordinate species increased their LUE. Our results suggest that greater light interception and greater LUE, generated by inter and intraspecific variation, together drive overyielding in mixed-species forests.
Bibliographical noteFunding Information:
We thank Raimundo Bermudez, Daniel Stangle and many interns for assistance with managing IDENT‐Cloquet and collecting data. We also thank three anonymous reviewers for comments that helped us to clarify and greatly improve the manuscript. The University of Minnesota (College of Biological Sciences, College of Food, Agricultural and Natural Resource Sciences, and Graduate School), a Fulbright Science and Technology Award, a Canada Chair grant to CM and the NSF Biology Integration Institutes program (NSF‐DBI‐2021898) financially supported this study.
© 2021 John Wiley & Sons Ltd.
- biodiversity–ecosystem function
- forest productivity
- functional diversity
- niche partitioning
- photosynthetic light-response
PubMed: MeSH publication types