[Diversity patterns in intertidal communities of three southern islands of Changshan archipelago]

The diversity pattern of intertidal communities in 3 southern islands of Changshan archipelago were studied. The results showed that the community appearance and structure in rocky intertidal zones of 3 islands were regimented by dominant species Chthamalus challengeri, Ostrea spp., macro-algae and Littorina brevicula, while in gravel intertidal zones of Southern Changshan and Daheishan regimented by Chthamalus challengeri, Littorina brevicula, Ostrea spp., and in Northern Changshan, by Chthamalus challengeri, macro-algae and Gaetice depressus. There existed no obvious difference in community structures of rocky intertidal zones among 3 islands, which was demonstrated by the similarity in first 5 dominant species and their dominance ranks in the community. However, a significant difference was achieved in gravel intertidal communities, in which, the dominant species in the community at Northern Changshan differed greatly from that of others. The community diversity in R, J, D(B), D(IV), H(B), and H(IV), in rocky intertidal communities among 3 islands showed a great coincidence, Northern Changshan > Southern Changshan > Daheishan, however, little coincident results were found among gravel intertidal communities. It was found that there existed a higher community diversity in gravel intertidal communities at Daheishan and Southern Changshan than at Northern Changshan where existed the highest species evenness. The community diversity was generally higher in gravel intertidal communities than in rocky intertidal ones. The variation in community compositions, structures and diversities were resulted mainly from topographical heterogeneities, substratum heterogeneities, hydrodynamics, water eutrophication and human disturbance in intertidal zones.