Root chemistry and soil fauna, but not soil abiotic conditions explain the effects of plant diversity on root decomposition

Hongmei Chen*, Natalie J. Oram, Kathryn E. Barry, Liesje Mommer, Jasper van Ruijven, Hans de Kroon, Anne Ebeling, Nico Eisenhauer, Christine Fischer, Gerd Gleixner, Arthur Gessler, Odette González Macé, Nina Hacker, Anke Hildebrandt, Markus Lange, Michael Scherer-lorenzen, Stefan Scheu, Yvonne Oelmann, Cameron Wagg, Wolfgang WilckeChristian Wirth, Alexandra Weigelt

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

6 Citations (Scopus)

Abstract

Plant diversity influences many ecosystem functions including root decomposition. However, due to the presence of multiple pathways via which plant diversity may affect root decomposition, our mechanistic understanding of their relationships is limited. In a grassland biodiversity experiment, we simultaneously assessed the effects of three pathways—root litter quality, soil biota, and soil abiotic conditions—on the relationships between plant diversity (in terms of species richness and the presence/absence of grasses and legumes) and root decomposition using structural equation modeling. Our final structural equation model explained 70% of the variation in root mass loss. However, different measures of plant diversity included in our model operated via different pathways to alter root mass loss. Plant species richness had a negative effect on root mass loss. This was partially due to increased Oribatida abundance, but was weakened by enhanced root potassium (K) concentration in more diverse mixtures. Equally, grass presence negatively affected root mass loss. This effect of grasses was mostly mediated via increased root lignin concentration and supported via increased Oribatida abundance and decreased root K concentration. In contrast, legume presence showed a net positive effect on root mass loss via decreased root lignin concentration and increased root magnesium concentration, both of which led to enhanced root mass loss. Overall, the different measures of plant diversity had contrasting effects on root decomposition. Furthermore, we found that root chemistry and soil biota but not root morphology or soil abiotic conditions mediated these effects of plant diversity on root decomposition.
Original languageEnglish
Pages (from-to)499-511
JournalOecologia
Volume185
Issue number3
Early online date19 Sep 2017
DOIs
Publication statusPublished - Nov 2017

Keywords

  • Functional groups
  • Jena Experiment
  • Root litter
  • SEM
  • Species richness

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