Supported by the National Natural Science Foundation (90102011) and National key Basic Research Special Funds (2002CB111505) of China.We thank Mr Wei-Dong Liu, Mr Guang-Li He, Ms Wen-Jing Liu, and Mr Bao-Hui Zhang for practical assistance. Thanks also to Dr Guang-Lian QIN for helpful advice on data analysis and to Drs Sa Xiao, Hui-Min Yang, Xin Luan, Ying Deng and You-Cai Xiong for helpful suggestions on an early version of the manuscript.
Communities with more species could have a greater variety of species' characteristics, leading to more effective use of limiting resources through niche partitioning (complementarity) and therefore greater product...