Abstract: East Taihu Lake is a typical grass-type shallow lake in the middle and lower reaches of the Yangtze River. To investigate the influence mechanism of different functional areas of East Taihu Lake on the macroinvertebrate communities, the effects of water and sediment factors in different functional areas on macroinvertebrate communities in East Taihu Lake were studied. A survey was conducted from October 2020 to November 2021 on macroinvertebrate communities, water and sediment factors at each sampling site in each functional area. 27 species of macrobenthos were collected in the study area, belonging to 3 phyla, 6 classes, 13 orders, 18 families and 23 genera. The mean values of annual macroinvertebrate density and biomass were (70.93±42.92) ind/m2and (50.99±36.50) g/m2, respectively. Water depth, total phosphorus (TP), chlorophyll a concentration, and sediment water content (MC), sorting coefficient (Sd), skewness (Sk), particle size distribution were significantly correlated with macroinvertebrate community distribution, particularly affecting the density and biomass of mollusks. This study indicated that environmental factors related to aquatic plants had a great influence on macroinvertebrate communities, and an aquatic revegetation strategy dominated by submerged plant restoration should be established. It provided scientific basis and theoretical reference for the ecological protection and restoration of shallow lakes, evaluation of aquatic ecological health, and management of aquatic ecological environment quality in the demonstration zone of the Yangtze River Delta.

Key words: East Taihu Lake, macroinvertebrates, community structure, water depth, ecological functional areas