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Trophic complexity enhances ecosystem functioning in an aquatic detritus-based model system

Jabiol, Jérémy and McKie, Brendan G. and Bruder, Andreas and Bernadet, Caroline and Gessner, Mark O. and Chauvet, Eric Trophic complexity enhances ecosystem functioning in an aquatic detritus-based model system. (2013) Journal of Animal Ecology, 82 (5). 1042-1051. ISSN 0021-8790

(Document in English)

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Official URL: http://dx.doi.org/10.1111/1365-2656.12079


1. Understanding the functional significance of species interactions in ecosystems has become a major challenge as biodiversity declines rapidly worldwide. Ecosystem consequences arising from the loss of diversity either within trophic levels (horizontal diversity) or across trophic levels (vertical diversity) are well documented. However, simultaneous losses of species at dif- ferent trophic levels may also result in interactive effects, with potentially complex outcomes for ecosystem functioning. 2. Because of logistical constraints, the outcomes of such interactions have been difficult to assess in experiments involving large metazoan species. Here, we take advantage of a detri- tus–based model system to experimentally assess the consequences of biodiversity change within both horizontal and vertical food-web components on leaf-litter decomposition, a fun- damental process in a wide range of ecosystems. 3. Our concurrent manipulation of fungal decomposer diversity (0, 1 or 5 species), detritivore diversity (0, 1 or 3 species), and the presence of predatory fish scent showed that trophic com- plexity is key to eliciting diversity effects on ecosystem functioning. Specifically, although fungi and detritivores tended to promote decomposition individually, rates were highest in the most complete community where all trophic levels were represented at the highest possible species richness. In part, the effects were trait-mediated, reflected in the contrasting foraging responses of the detritivore species to predator scent. 4. Our results thus highlight the importance of interactive effects of simultaneous species loss within multiple trophic levels on ecosystem functioning. If a common phenomenon, this out- come suggests that functional ecosystem impairment resulting from widespread biodiversity loss could be more severe than inferred from previous experiments confined to varying diver- sity within single trophic levels.

Item Type:Article
HAL Id:hal-03523154
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 > Sveriges lantbruksuniversitet - SLU (SWEDEN)
Other partners > Eidgenössische Technische Hochschule Zürich - ETHZ (SWITZERLAND)
Laboratory name:
Deposited On:12 Mar 2014 12:03

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