Abstract: Substrate suitability is critical to the restoration of submersed macrophytes in shallow eutrophic lakes. Since benthic animals are good indicators of sediment eutrophication, the authors conducted a pioneer study during 2002~2003 in Yuehu Lake, a hypertrophic urban lake of Wuhan City, with the purpose to explore the indicative value of macrobenthos distribution in determining macrophyterestorable area. First, by correlating density and biomass of different benthos with trophic variables of sediment, density of Tubificidae (Oligochaeta) was selected as the best indicator. Secondly, on the basis of the data from 16 Yangtze lakes, a significant negative relationship between tubificids and macrophytes was detected, and it is demonstrated that the sediment with tubificids less than 100 ind/m2 could be suitable for macrophyte growth. Finally, the horizontal isograms of tubificid density in Yuehu Lake were drawn, showing two proper places for macrophyte restoration. As the first attempt, the authors have established a principal framework for indicating macrophyterestorable area by macrobenthos distribution, and will focus on the threshold analysis in the future.

Key words: macrobenthos, tubificid isograms, threshold for macrophyte restoration, eutrophic shallow lake, Yuehu Lake in Wuhan City