STUDIES ON COMMUNITY STRUCTURE AND DYNAMICS OF ZOOBENTHOS IN LAKE DONG HU, WUHAN

Investigations on zoobenthos in Lake Dong Hu (Tung-Hu) of Wuhan, HubeiProvince, were undertaken during 1973-1975. The results may be summarized asfollows: 1. Zoobenthic community of the Lake is chiefly composed of 5 species of aquaticoligochaetes, 15 species of molluscs and 12 genera of aquatic insects. Among them,Branchiura sowcrbyi, Limnodrilus hoffmeisteri, Bellamya aeruginosa, Parafossarulusstriatula and the Chironomid species belonging to the genera Pelopia, Procladius and Einfeldius are predominant. 2. The annual standing crops of zoobenthos in the Lake during the surveyingperiod were 362-462 ind. m-2 in density and 38.2-72.1 gm-2 in biomass. It was foundthat the standing crops were lower in June-July and higher after October in each year. 3. Standing crops varied with the three subregions of the Lake. Higher valueswere always obtained in the subregion Shuiguohu, a bay receiving a larger amount ofsewage water, while the lower values were found in the subregion Guozhenghu, thelargest openwater area in the Lake. 4. Standing crops including oligochaetes and insects in various subregions werefound to be correlated positively to the total nitrogen and to the total phosphorus inthe water. Regression formulae calculated from biological and environmental variablesshowed that both density and biomass of the animals would increase exponentially whenphosphoric compounds increase even at ppb level and thus total phosphorus is consi-dered to be the most important factor limiting the abundance of the benthic macroin-vertebrates. 5. Suggestions concerning fishery management and water quality monitoring ofthe Lake based on some zoobenthic parameters are offered.