BACKGROUND AND AIMS: The biomass-ratio hypothesis states that ecosystem properties are driven by the characteristics of dominant species in the community. In this study, the hypothesis was operationalized as community-weighted means (CWMs) of monoculture values and tested for predicting the decomposition of multispecies litter mixtures along an abiotic gradient in the field. METHODS: Decomposition rates (mg g(-1) d(-1)) of litter from four herb species were measured using litter-bed experiments with the same soil at three sites in central France along a correlated climatic gradient of temperature and precipitation. All possible combinations from one to four species mixtures were tested over 28 weeks of incubation. Observed mixture decomposition rates were compared with those predicted by the biomass-ratio hypothesis. Variability of the prediction errors was compared with the species richness of the mixtures, across sites, and within sites over time. KEY RESULTS: Both positive and negative prediction errors occurred. Despite this, the biomass-ratio hypothesis was true as an average claim for all sites (r = 0·91) and for each site separately, except for the climatically intermediate site, which showed mainly synergistic deviations. Variability decreased with increasing species richness and in less favourable climatic conditions for decomposition. CONCLUSIONS: Community-weighted mean values provided good predictions of mixed-species litter decomposition, converging to the predicted values with increasing species richness and in climates less favourable to decomposition. Under a context of climate change, abiotic variability would be important to take into account when predicting ecosystem processes.
BACKGROUND AND AIMS: The biomass-ratio hypothesis states that ecosystem properties are driven by the characteristics of dominant species in the community. In this study, the hypothesis was operationalized as community-weighted means (CWMs) of monoculture values and tested for predicting the decomposition of multispecies litter mixtures along an abiotic gradient in the field. METHODS: Decomposition rates (mg g(-1) d(-1)) of litter from four herb species were measured using litter-bed experiments with the same soil at three sites in central France along a correlated climatic gradient of temperature and precipitation. All possible combinations from one to four species mixtures were tested over 28 weeks of incubation. Observed mixture decomposition rates were compared with those predicted by the biomass-ratio hypothesis. Variability of the prediction errors was compared with the species richness of the mixtures, across sites, and within sites over time. KEY RESULTS: Both positive and negative prediction errors occurred. Despite this, the biomass-ratio hypothesis was true as an average claim for all sites (r = 0·91) and for each site separately, except for the climatically intermediate site, which showed mainly synergistic deviations. Variability decreased with increasing species richness and in less favourable climatic conditions for decomposition. CONCLUSIONS: Community-weighted mean values provided good predictions of mixed-species litter decomposition, converging to the predicted values with increasing species richness and in climates less favourable to decomposition. Under a context of climate change, abiotic variability would be important to take into account when predicting ecosystem processes.
Authors: William K Cornwell; Johannes H C Cornelissen; Kathryn Amatangelo; Ellen Dorrepaal; Valerie T Eviner; Oscar Godoy; Sarah E Hobbie; Bart Hoorens; Hiroko Kurokawa; Natalia Pérez-Harguindeguy; Helen M Quested; Louis S Santiago; David A Wardle; Ian J Wright; Rien Aerts; Steven D Allison; Peter van Bodegom; Victor Brovkin; Alex Chatain; Terry V Callaghan; Sandra Díaz; Eric Garnier; Diego E Gurvich; Elena Kazakou; Julia A Klein; Jenny Read; Peter B Reich; Nadejda A Soudzilovskaia; M Victoria Vaieretti; Mark Westoby Journal: Ecol Lett Date: 2008-07-08 Impact factor: 9.492
Authors: Claire Fortunel; Eric Garnier; Richard Joffre; Elena Kazakou; Helen Quested; Karl Grigulis; Sandra Lavorel; Pauline Ansquer; Helena Castro; Pablo Cruz; Jirí Dolezal; Ove Eriksson; Helena Freitas; Carly Golodets; Claire Jouany; Jaime Kigel; Michael Kleyer; Veiko Lehsten; Jan Leps; Tonia Meier; Robin Pakeman; Maria Papadimitriou; Vasilios P Papanastasis; Fabien Quétier; Matt Robson; Marcelo Sternberg; Jean-Pierre Theau; Aurélie Thébault; Maria Zarovali Journal: Ecology Date: 2009-03 Impact factor: 5.499
Authors: Aidan M Keith; René Van der Wal; Rob W Brooker; Graham H R Osler; Stephen J Chapman; David F R P Burslem; David A Elston Journal: Ecology Date: 2008-09 Impact factor: 5.499