Abstract: In May and August, 2004-2010, an investigation was conducted on the macrobenthos diversity in the southern intertidal zone of the Yellow River Delta. A total of 89 macrobenthos species were collected, most of which were polychaetes, crustacean, and mollusks, accounting for 34.8%, 29.2% and 27.0% of the total, respectively. Helice tientsinensis and Macrophthalmus japonicas were the dominant species in high tidal zone, while Potamocorbula laevis, Bullacta exarata, Umbonium thomasi, and Mactra veseriformis were dominated in mid and low tidal zones. The average Shannon index, Margalef index, and Pielou evenness index were 146, 115, and 0.66, respectively, and the Shannon index and Pielou index showed an upward trend. The species distribution had an obvious difference in different tidal zones, but less difference among years, which was also shown by cluster analysis. Due to the changes of habitat conditions since 2005 when the dams were established, the bioresources in the high tide zone increased obviously. As compared with historical data, the composition of dominant species in the study area in 2004-2010 was relatively stable, but the polychaetes occupied larger proportion, which was related to the human activities and the eco-environment change.

Key words: ecological risk, stakeholders, risk identification., ecological migrant settlement