Abstract: Tidal action can change the water level of marsh habitats, with consequence on plant growth and interspecific relationships. A controlled greenhouse experiment was carried out toexamine the effects of water level on the relationship between the alien, clonal speciesSpartina anglica and native speciesScirpus triqueter. Three water levels (flooding with 5 cm over substrate surface; flooding with 0 cm over substrate surface; drain away water from 5 cm under substrate surface) were crossed with five planting arrangements (two alien plants per pot, two native plants per pot, four alien plants per pot, four native plants per pot, four plants per pot with two alien and two native plants) to explore the effects of water level on inter and intra specific relationships ofS. anglica andS. triqueter. The results showed that water level had significant effects on root biomass and leaf number of S. anglica andS. triqueter. The planting pattern had significant effects on the growth and reproduction of both species. The inter and intraspecific relative neighborhood effect indices of both species were negative in all water levels. The intra specific relative neighborhood effect index of S. anglica was significantly higher than that at interspecific level. There was no significant difference between the inter and intra specific relative neighborhood effect indices ofS. triqueter. In conclusion, water level altered intra and inter specific relationships of S. anglica andS. triqueter. The distribution ofS. anglica could be effectively controlled by proper regulation of water level and restoration of native species in Chinese coastal zone.

Key words: biochar, continuous cropping soil, Biolog method, microbial diversity, nutrition