Abstract The relationship between biodiversity and ecosystem functioning has aroused considerable interest and controversy in recent ecological literature. From an explosion of recent experimental and theoretical research addressing this question, several key advances have emerged. (1) Long-term and large scale perspectives on the relationship between biodiversity and ecosystem functioning have been highlighted. A hypothetical transition from sampling to complementarity has been proposed based on the results of the largest and longest running experiments, the Cedar Creek Diversity Experiments. Their hypothesis suggests that the positive effect of diversity on ecosystem processes in experimental studies initially arises as a result of sampling. But a transition from sampling to complementarity occurs after a time lag. It can be predicted that niche complementarity is the long-term mechanism underlying the diversity-ecosystem functioning relationship, causing an over-yielding effect. (2) Some experimental studies were conducted to explore the interaction between abiotic factors and the biodiversity-ecosystem functioning relationship. The results indicate that resource availability and environmental disturbance may dominate and alter the relationship between species diversity and ecosystem productivity. It is suggested that the positive effects of biodiversity on ecosystem functioning in natural systems are likely masked by variation in environmental factors among habitats. (3) Several papers highlight the role of trophic interactions in the relationship between biodiversity and ecosystem functioning. The general mechanisms explaining plant diversity effects on primary productivity, i.e. sampling and complementarity effects, have been extended to include consumer prey interactions. This leads to the prediction that a more diverse consumer assemblage should have stronger impacts on aggregate prey abundance than a depauperate one. (4) Theoretical studies highlight mechanisms of species coexistence as the key to understanding the relationship between diversity and ecosystem functioning. The varied diversity-productivity relationships from models with different species coexistence mechanisms imply that no general diversity productivity pattern exists, and that the nature of the biodiversity-ecosystem functioning relationship depends on species coexistence mechanisms.