title: C, N and P fertilization in an Amazonian rainforest supports stoichiometric dissimilarity as a driver of litter diversity effects on decomposition.
abstract: Plant leaf litter generally decomposes faster as a group of different species than when individual species decompose alone, but underlying mechanisms of these diversity effects remain poorly understood. Because resource C : N : P stoichiometry (i.e. the ratios of these key elements) exhibits strong control on consumers, we supposed that stoichiometric dissimilarity of litter mixtures (i.e. the divergence in C : N : P ratios among species) improves resource complementarity to decomposers leading to faster mixture decomposition. We tested this hypothesis with: (i) a wide range of leaf litter mixtures of neotropical tree species varying in C : N : P dissimilarity, and (ii) a nutrient addition experiment (C, N and P) to create stoichiometric similarity. Litter mixtures decomposed in the field using two different types of litterbags allowing or preventing access to soil fauna. Litter mixture mass loss was higher than expected from species decomposing singly, especially in presence of soil fauna. With fauna, synergistic litter mixture effects increased with increasing stoichiometric dissimilarity of litter mixtures and this positive relationship disappeared with fertilizer addition. Our results indicate that litter stoichiometric dissimilarity drives mixture effects via the nutritional requirements of soil fauna. Incorporating ecological stoichiometry in biodiversity research allows refinement of the underlying mechanisms of how changing biodiversity affects ecosystem functioning.
authors.affiliation: Centre d'Ecologie Fonctionnelle et Evolutive (CEFE UMR 5175, CNRS-Université de Montpellier-Université Paul-Valéry Montpellier-EPHE), 1919 Route de MENDE, 34293 Montpellier Cedex 5, France Ecology of Guiana Forest ECOFOG UMR 745, INRA-CIRAD-CNRS-UAG-AgroParisTech, INRA Campus Agronomique, BP 16, Kourou Cedex 97310, France Royal Holloway University of London, Egham, Surrey TW20 0EX, UK sandra.barantal@gmail.com.
authors.forename: Sandra
authors.initials: S
authors.lastname: Barantal
authors.affiliation: Ecology of Guiana Forest ECOFOG UMR 745, INRA-CIRAD-CNRS-UAG-AgroParisTech, INRA Campus Agronomique, BP 16, Kourou Cedex 97310, France.
authors.forename: Heidy
authors.initials: H
authors.lastname: Schimann
authors.affiliation: Centre d'Ecologie Fonctionnelle et Evolutive (CEFE UMR 5175, CNRS-Université de Montpellier-Université Paul-Valéry Montpellier-EPHE), 1919 Route de MENDE, 34293 Montpellier Cedex 5, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Fromin
authors.affiliation: Centre d'Ecologie Fonctionnelle et Evolutive (CEFE UMR 5175, CNRS-Université de Montpellier-Université Paul-Valéry Montpellier-EPHE), 1919 Route de MENDE, 34293 Montpellier Cedex 5, France.
authors.forename: Stephan
authors.initials: S
authors.lastname: Hättenschwiler
mesh_terms: D044822:Biodiversity; D002244:Carbon / Q000378:metabolism*; D017753:Ecosystem; D009584:Nitrogen / Q000378:metabolism*; D010758:Phosphorus / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism; D065947:Rainforest; D012987:Soil
chemical_list: D012987:Soil; D010758:Phosphorus; D002244:Carbon; D009584:Nitrogen
keywords: litter diversity; neotropical forest; nutrient addition; soil fauna; stoichiometry; trait dissimilarity