4Jing S R. Nutrient removal from polluted river water by using constructed wetlands [ J ]. Bioresource Technology, 2001,76 ( 2 ) : 131--135.
5Hughs J B,Roughgarden J. Aggregate community properties and the strength of species interaction [ J].Proceeding of Nature Aca- demic Science of U. S. A ,1998,95 : 6837--6842.
