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Litter diversity, fungal decomposers and litter decomposition under simulated stream intermittency

Bruder, Andreas and Chauvet, Eric and Gessner, Mark O. Litter diversity, fungal decomposers and litter decomposition under simulated stream intermittency. (2011) Functional Ecology, 25 (6). 1269-1277. ISSN 0269-8463

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Official URL: http://dx.doi.org/10.1111/j.1365-2435.2011.01903.x


1. The drying of stream channels resulting from flow interruption is expected to increase as a consequence of climate change. Implications for aquatic organisms and processes are profound. We assessed whether riparian diversity can partially buffer against consequences of drying on fungal decomposers and leaf litter decomposition, an important ecosystem process. 2. Our central hypothesis was that during dry periods recalcitrant leaf litter with high water- holding capacity would extend the window of opportunity for microbial activity in less recalci- trant litter when both litter types are mixed, and that this would lead to a positive litter diversity effect on decomposition. To test for such interactive effects, we conducted a diversity experiment in a Mediterranean stream, in which alder and oak litter, and a mixture of both, was subjected to various drying regimes differing in intensity and timing. 3. Drying regime affected both fungal decomposers and the decomposition rate of alder litter. Effects were observed both immediately and 3 weeks after stream flow resumed. Small differences in the timing of the dry period influenced both decomposition rate and measures of fungal performance (i.e. biomass and sporulation activity). Litter mixing, in contrast, had no effect on either decomposition or fungal decomposers, although mixing increased moisture retention in alder litter as required for the mechanism hypothesized to lead to a diversity effect. 4. Given the contrasting traits of the litter types used in the experiment, our results imply that riparian tree diversity is unlikely to buffer against increased frequencies of stream flow disruption expected in the face of climate change. It appears, however, that the precise timing of dry periods and high-flow events will strongly influence the extent to which stream food webs can exploit the resources supplied by riparian vegetation in the form of leaf litter.

Item Type:Article
Additional Information:Thanks to Wiley-Blackwell editor. The definitive version is available at http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2435.2011.01903.x/abstract
HAL Id:hal-03469120
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Other partners > Leibniz-Institut für Gewässerökologie und Binnenfischerei - IGB (GERMANY)
Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Other partners > Technische Universität Berlin - TU Berlin (GERMANY)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
Other partners > Swiss Federal Institute of Aquatic Science and Technology - EAWAG (SWITZERLAND)
Other partners > Eidgenössische Technische Hochschule Zürich - ETHZ (SWITZERLAND)
Laboratory name:
Deposited On:21 Mar 2014 14:10

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