University of Oulu

Pichon, N. A., Cappelli, S. L., & Allan, E. (2022). Intraspecific trait changes have large impacts on community functional composition but do not affect ecosystem function. Journal of Ecology, 110, 644– 658.

Intraspecific trait changes have large impacts on community functional composition but do not affect ecosystem function

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Author: Pichon, Noémie A.1,2; Cappelli, Seraina L.2,3; Allan, Eric2,4
Organizations: 1Department of Ecology and Genetics, University of Oulu, Oulu, Finland
2Institute of Plant Sciences, University of Bern, Bern, Switzerland
3Research Centre for Ecological Change, University of Helsinki, Helsinki, Finland
4Centre for Development and the Environment, University of Bern, Bern, Switzerland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.6 MB)
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Language: English
Published: John Wiley & Sons, 2022
Publish Date: 2022-08-01


1. Plant functional traits can provide a mechanistic understanding of community responses to global change and of community effects on ecosystem functions. Nitrogen enrichment typically shifts trait composition by promoting the dominance of acquisitive plants (high specific leaf area [SLA] and low leaf dry matter content [LDMC]), translating into high biomass production. Changes in mean trait values can be due to shifts in species identity, relative abundances and/or intraspecific trait values. However, we do not know the relative importance of these shifts in determining trait responses to environmental changes, or trait effects on ecosystem functioning, such as biomass production.

2. We quantified the relative importance of species composition, abundance and intraspecific shifts in driving variation in SLA and LDMC, and how these shifts affected above- and below-ground biomass. We measured traits in a grassland experiment manipulating nitrogen fertilisation, plant species richness, foliar fungal pathogen removal and sown functional composition (slow vs. fast species). We fitted structural equation models to test the importance of abundance and intraspecific shifts in determining (a) responses of functional composition to treatments and (b) effects on above- and below-ground biomass.

3. We found that species intraspecific shifts were as important as abundance shifts in determining the overall change in functional composition (community weighted mean trait values), and even had large effects compared to substantial initial variation in sown trait composition. Intraspecific trait shifts resulted in convergence towards intermediate SLA in diverse communities; although convergence was reduced by nitrogen addition and enhanced by pathogen removal. In contrast, large intraspecific shifts in LDMC were not influenced by the treatments. However, despite large responses, intraspecific trait shifts had no effect on above- or below-ground biomass. Only interspecific trait variation affected functioning: below-ground biomass was reduced by SLA and increased by LDMC, while above-ground biomass was increased by SLA.

4. Synthesis. Our results add to a growing body of literature showing large intraspecific trait variation and emphasise the importance of using field collected data to determine community functional composition. However, they also show that intraspecific variation does not necessarily affect ecosystem functioning and therefore response–effect trait relationships may differ between versus within species.

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Series: Journal of ecology
ISSN: 0022-0477
ISSN-E: 1365-2745
ISSN-L: 0022-0477
Volume: 110
Issue: 3
Pages: 644 - 658
DOI: 10.1111/1365-2745.13827
Type of Publication: A1 Journal article – refereed
Field of Science: 1183 Plant biology, microbiology, virology
1172 Environmental sciences
Funding: Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung. Grant Number: 31003A_160212
Copyright information: © 2021 The Authors. Journal of Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.