Root chemistry and soil fauna, but not soil abiotic conditions explain the effects of plant diversity on root decomposition
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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.
KeywordsSpecies richness Functional groups Root litter Jena Experiment SEM
The Jena Experiment was funded by the German Science Foundation (DFG, FOR 1451) and was supported by the Friedrich-Schiller-University Jena and the Max Planck Society. We thank the gardeners of the Jena Experiment for maintaining the plots and student helpers for the field work and sample preparation.
Root mass loss, root C:N ratio, and soil water content are deposited at the Jena Experiment database and will be accessible via Dryad Digital Repository http://dx.doi.org/10.5061/dryad.6k23f (Chen et al. 2017). The rest of the data are deposited at the Jena Experiment database and will be deposited at Pangaea (http://www.pangaea.de).
Author contribution statement
LM, JR, AG, MSL, and AW designed the experiment. HC, CF, OGM, NH, and ML collected the data. HC analyzed the data and wrote the manuscript with input from KB and AW. All authors provided input on the final written manuscript.
Compliance with ethical standards
The Jena Experiment was funded by the German Science Foundation (DFG, FOR 1451). LM was funded by the Netherlands Organisation for Scientific Research (NWO, Vidi Grant 864.14.006). MSL was funded by the DFG (Gl262/14 and Gl262/19). YO was funded by the DFG (Oe516/3-2), WW was funded by the DFG (Wi1601/4) and the Swiss National Science Foundation (SNF, 200021E-131195/1).
Conflict of interest
The authors declare that they have no conflict of interest.
All applicable institutional and/or national guidelines for the care and use of animals were followed.
- Burnham KP, Anderson DR (2007) Model selection and multimodel inference: a practical information-theoretic approach. Springer Science and Business Media, New YorkGoogle Scholar
- Cardon ZG, Whitbeck JL (2011) The rhizosphere: an ecological perspective. Elsevier Academic Press, BurlingtonGoogle Scholar
- Chapin FS III, Matson PA, Mooney HA (2002) Principles of terrestrial ecosystem ecology, 2nd edn. Springer-Verlag New York, Inc., New YorkGoogle Scholar
- Coleman DC, Crossley DA Jr, Hendrix PF (2004) Fundamentals of soil ecology, 2nd edn. Elsevier Academic Press, BurlingtonGoogle Scholar
- Harrell FE Jr, Dupont C et al (2016) Hmisc: Harrell miscellaneous. https://CRAN.R-project.org/package=Hmisc
- Hoffmann K, Bivour W, Früh B et al (2014) Klimauntersuchungen in Jena für die Anpassung an den Klimawandel und seine erwarteten Folgen. Deutscher Wetterdienst, Offenbach am MainGoogle Scholar
- Kempson D, Lloyd M, Ghelardi R (1963) A new extractor for woodland litter. Pedobiologia 3:1–21Google Scholar
- Kline RB (2005) Principles and practice of structural equation modeling, 2nd edn. Guilford Press, New YorkGoogle Scholar
- Kuo S (1996) Phosphorus. In: Sparks DL, Page AL, Helmke PA, Loeppert RH (eds) Methods of soil analysis. Part 3. Chemical methods. Soil Science Society of America, Inc., American Society of Agronomy, Inc., MadisonGoogle Scholar
- Li X, Han S, Zhang Y (2007) Foliar decomposition in a broadleaf-mixed Korean pine (Pinus koraiensis Sieb. Et Zucc) plantation forest: the impact of initial litter quality and the decomposition of three kinds of organic matter fraction on mass loss and nutrient release rates. Plant Soil 295:151–167CrossRefGoogle Scholar
- Marschner H (1995) Mineral nutrition of higher plants, 2nd edn. Academic Press Limited, LondonGoogle Scholar
- Mommer L, Visser E, PrometheusWiki contributors (2011) Root distribution in soils I. Root core sampling and destructive pot harvests. Prometheus Wiki, CSIRO Publishing, Clayton SouthGoogle Scholar
- Peverill KI, Sparrow LA, Reuter DJ (1999) Soil analysis: an interpretation manual. CSIRO Publishing, CollingwoodGoogle Scholar
- R Core Team (2016) R: a language and environment for statistical computing. R Foundation for Statistical Computing, ViennaGoogle Scholar
- Schaefer M (ed) (2009) Brohmer Fauna von Deutschland: Ein Bestimmungsbuch unserer Heimischen Tierwelt, 23rd edn. Quelle & Meyer Verlag, WiebelsheimGoogle Scholar
- Schneider K, Renker C, Scheu S, Maraun M (2004) Feeding biology of oribatid mites: a minireview. Phytophaga 14:247–256Google Scholar
- Sterner RW, Elser JJ (2002) Ecological stoichiometry: the biology of elements from molecules to the biosphere. Princeton University Press, PrincetonGoogle Scholar
- Swift MJ, Heal OW, Anderson JM (1979) Decomposition in terrestrial ecosystems. University of California Press, BerkeleyGoogle Scholar
- Wardle DA (2002) Communities and ecosystems: linking the aboveground and belowground components. Princeton University Press, PrincetonGoogle Scholar