Moderate plant–soil feedbacks have small effects on the biodiversity–productivity relationship: A field experiment |
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| Authors: | Josephine Grenzer Andrew Kulmatiski Leslie Forero Anne Ebeling Nico Eisenhauer Jeanette Norton |
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| Affiliation: | 1. Department of Wildland Resources and the Ecology Center, Utah State University, Logan UT, USA ; 2. Institute of Ecology and Evolution, University of Jena, Jena Germany ; 3. German Centre for Integrative Biodiversity Research (iDiv), Halle‐Jena‐Leipzig, Leipzig Germany ; 4. Institute of Biology, University of Leipzig, Leipzig Germany ; 5. Department of Plant, Soils and Climate, Utah State University, Logan UT, USA |
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| Abstract: | Plant–soil feedback (PSF) has gained attention as a mechanism promoting plant growth and coexistence. However, most PSF research has measured monoculture growth in greenhouse conditions. Translating PSFs into effects on plant growth in field communities remains an important frontier for PSF research. Using a 4‐year, factorial field experiment in Jena, Germany, we measured the growth of nine grassland species on soils conditioned by each of the target species (i.e., 72 PSFs). Plant community models were parameterized with or without these PSF effects, and model predictions were compared to plant biomass production in diversity–productivity experiments. Plants created soils that changed subsequent plant biomass by 40%. However, because they were both positive and negative, the average PSF effect was 14% less growth on “home” than on “away” soils. Nine‐species plant communities produced 29 to 37% more biomass for polycultures than for monocultures due primarily to selection effects. With or without PSF, plant community models predicted 28%–29% more biomass for polycultures than for monocultures, again due primarily to selection effects. Synthesis: Despite causing 40% changes in plant biomass, PSFs had little effect on model predictions of plant community biomass across a range of species richness. While somewhat surprising, a lack of a PSF effect was appropriate in this site because species richness effects in this study were caused by selection effects and not complementarity effects (PSFs are a complementarity mechanism). Our plant community models helped us describe several reasons that even large PSF may not affect plant productivity. Notably, we found that dominant species demonstrated small PSF, suggesting there may be selective pressure for plants to create neutral PSF. Broadly, testing PSFs in plant communities in field conditions provided a more realistic understanding of how PSFs affect plant growth in communities in the context of other species traits. |
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| Keywords: | aboveground– belowground interactions, biodiversity– ecosystem functioning, biomass, dominance, plant community model, plant identity |
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