Resource availability and biodiversity effects on the productivity, temporal variability and resistance of experimental algal communities

Resource availability is important for biodiversity dynamics and community structure, and might alter biodiversity effects on ecosystem productivity and stability. We independently manipulated nutrient availability and species richness in aquatic algal microcosms. Little effect of species richness on biomass production was detected in either high or low nutrient microcosms. However, relative yield analysis and an additive partitioning method indicated greater complementarity effects in low than in high nutrient microcosms, and the complementarity effect showed no trend through time. The effect of species richness on the temporal variability of community was neutral in nutrient-rich environment, while a stabilizing effect of diversity was found in nutrient-poor environment. During a cold perturbation compensatory growth among species was present only in the nutrient-poor environment, while community biomass was reduced only in the nutrient-rich environment. The responses of community and constituent species to cold perturbation were diversity-independent in each environment. Our results suggest that further investigations are needed into the effect of environmental context on the relationships between biodiversity, ecosystem processes, and ecosystem stability.