Drought decreases incorporation of recent plant photosynthate into soil food webs regardless of their trophic complexity.

Autor: Chomel M; School of Earth and Environmental Sciences, The University of Manchester, Manchester, UK., Lavallee JM; School of Earth and Environmental Sciences, The University of Manchester, Manchester, UK.; Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO, USA., Alvarez-Segura N; Marine and Continental Waters Program, IRTA, Sant Carles de la Ràpita, Catalonia, Spain., de Castro F; AgriFood & Biosciences Institute, Belfast, UK., Rhymes JM; School of Earth and Environmental Sciences, The University of Manchester, Manchester, UK.; School of Geography, Earth and Environmental Sciences, University of Plymouth, Plymouth, UK., Caruso T; School of Biological Sciences and Institute for Global Food Security, Queen's University of Belfast, Belfast, UK., de Vries FT; Institute of Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands., Baggs EM; Global Academy of Agriculture and Food Security, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, UK., Emmerson MC; School of Biological Sciences and Institute for Global Food Security, Queen's University of Belfast, Belfast, UK., Bardgett RD; School of Earth and Environmental Sciences, The University of Manchester, Manchester, UK., Johnson D; School of Earth and Environmental Sciences, The University of Manchester, Manchester, UK.
Jazyk: angličtina
Zdroj: Global change biology [Glob Chang Biol] 2019 Oct; Vol. 25 (10), pp. 3549-3561. Date of Electronic Publication: 2019 Aug 10.
DOI: 10.1111/gcb.14754
Abstrakt: Theory suggests that more complex food webs promote stability and can buffer the effects of perturbations, such as drought, on soil organisms and ecosystem functions. Here, we tested experimentally how soil food web trophic complexity modulates the response to drought of soil functions related to carbon cycling and the capture and transfer below-ground of recent photosynthate by plants. We constructed experimental systems comprising soil communities with one, two or three trophic levels (microorganisms, detritivores and predators) and subjected them to drought. We investigated how food web trophic complexity in interaction with drought influenced litter decomposition, soil CO 2 efflux, mycorrhizal colonization, fungal production, microbial communities and soil fauna biomass. Plants were pulse-labelled after the drought with 13 C-CO 2 to quantify the capture of recent photosynthate and its transfer below-ground. Overall, our results show that drought and soil food web trophic complexity do not interact to affect soil functions and microbial community composition, but act independently, with an overall stronger effect of drought. After drought, the net uptake of 13 C by plants was reduced and its retention in plant biomass was greater, leading to a strong decrease in carbon transfer below-ground. Although food web trophic complexity influenced the biomass of Collembola and fungal hyphal length, 13 C enrichment and the net transfer of carbon from plant shoots to microbes and soil CO 2 efflux were not affected significantly by varying the number of trophic groups. Our results indicate that drought has a strong effect on above-ground-below-ground linkages by reducing the flow of recent photosynthate. Our results emphasize the sensitivity of the critical pathway of recent photosynthate transfer from plants to soil organisms to a drought perturbation, and show that these effects may not be mitigated by the trophic complexity of soil communities, at least at the level manipulated in this experiment.
(© 2019 The Authors. Global Change Biology published by John Wiley & Sons Ltd.)
Databáze: MEDLINE
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