Ecosystem maturity and performance

Arising from: Bai, Y., Han, X., Wu, J., Chen, Z. & Li, L. Nature, 431, 181–184 (2004); see also communication from Wang et al.; Bai, Y., Han, X., Wu, J., Chen, Z. & Li, L. reply.The effect of maturity, or successional stage, on ecosystem performance (measured as productivity or stability, for example) is important for both basic ecology and ecosystem management. On the basis of the results of a long-term study of two different plant communities at two sites in the Inner Mongolia grassland1, Bai et al. claim that these communities simultaneously achieve high species richness, productivity and ecosystem stability at the late successional stage1. However, I question their interpretation of the data and suggest that this claim is undermined by evidence from other empirical and theoretical studies.