Predicting mixed-species litter decomposition

The biomass-ratio hypothesis states that ecosystem properties are driven by the characteristics of dominant species in the community. Tardif et al.  measure decomposition rates of litter from four herb species at three sites along a correlated climatic gradient of temperature and precipitation in order to test the predictive value of the hypothesis. They find that community-weighted means of monoculture values provide good predictions of mixed-species’ litter decomposition, converging to the predicted values with increasing species richness and in climates less favourable to decomposition. The results support the idea that the biomass-ratio hypothesis, operationalized as community-weighted means, could offer the opportunity to predict ecosystems processes at larger spatial scales and in a changing environment.