Abstract: Based on the investigation data of the benthos at 8 sampling locations in Xiaoqing estuary and at 8 locations in Yellow River estuary in July 2008, a comparative study was made on the diversity characteristics (species composition, biodiversity pattern, and stability) of the benthic communities in the two estuaries by using various diversity indices, and analyzed the relationships between the diversity characteristics and 14 water environmental variables by adopting Spearman correlation analysis. In Xiaoqing estuary, a total of 38 macrobenthos species were recorded, belonging to 4 phyla, 6 classes, 17 orders, 35 families, and 37 genera, with the value of average taxonomic distinctness being 85.7 and that of the variation in taxonomic distinctness being 5856. In Yellow River estuary, there were 48 species of macrobenthos in total, belonging to 6 phyla, 9 classes, 24 orders, 42 families, and 45 genera, with the value of average taxonomic distinctness being 89.3 and that of the variation in taxonomic distinctness being 435.8. The Shannon index (H′) of the macrobenthos in Xiaoqing estuary was lower, only one-third of that in Yellow River estuary. The Spearman correlation analysis showed that the H′ had significant negative correlations with the water body’s ammonium, nitrate, Cu, and Hg contents, suggesting that the diversity of benthic communities in Xiaoqing estuary decreased with increasing eutrophication, and the large input of nutrient nitrogen and heavy metals pollution had definite negative impacts on the macrobenthos community in the estuary. The abundance biomass comparison (ABC) curve and the W-statistic value generated by PRIMER software showed that the abundance curves were intersection with the biomass curve in Xiaoqing estuary, indicating that the present benthic communities in the estuary were moderately disturbed. The benthic opportunistic polychaetes amphipods (BOPA) index indicated that the 4 stations in Xiaoqing estuary had suffered different degrees of environmental pollution. The discharge of sewage and industrial wastewater could bring great impact on the ecological characteristics of the benthic communities in Xiaoqing estuary, and thus, it was of significance to improve the management of industrial and domestic sewage discharge, intensify clean production, and strengthen the governance of industrial pollution sources to restore the water quality and improve the ecological environment of Xiaoqing estuary.

Key words: Quercus variabilis, DIVA-GIS, geographic distribution, potential distribution area.