Community characteristics of macrobenthos in waters around the Nature Reserve of the Chinese sturgeon Acipenser sinensis and the adjacent waters in Yangtze River Estuary

Abstract

Based on the macrobenthos taken at 15 stations from May, 2004 to February 2005 (Year 2004–2005), from August, 2005 to May, 2006 (Year 2005–2006) and from August, 2007 to May, 2008 (Year 2007–2008) in the Nature Reserve of Chinese sturgeon Acipenser sinensis of the Yangtze River Estuary, the species composition of food organisms, their biomass and abundance were determined. Analysis on species composition, biomass, density, and benthos community dynamic trend were discussed. Sixty-nine species occurred in the epifauna with the dominance of species obviously changing as the season’s progressed. The biomass and habitat density of the epifauna were 11.85 g per 100 m2 and 6.98 ind. per 100 m2, respectively. The community index indicates that the community is instable. The biomass of the epifauna declined from the 1st year to the 3rd year. From year 2004–2005 to year 2005–2006, the Shannon-Wiener index of diversity of the epifauna declined from 1.66 to 1.33 and got 1.24 in year 2007–2008. Overall, the Shannon-Wiener biodiversity indices of the 3 years were low and the community structures were instable. The species composition of fishes was reduced from 33 to 19% while the one for crustacea rose from 28 to 51% during the 3 years. It was proven that the community structures has some changed in recent years, especially the decline of fish proportion in the Yangtze River Nature Reserve for Chinese sturgeon, it is maybe not in favor of the protect of the Chinese sturgeon population. Therefore, relevant management and conversation should be reinforced.