QUANTITATIVE ANALYSIS ON THE MAIN SUBMERGED COMMUNITIES IN HONGHU LAKE. Ⅱ. POTAMOGETON MAACKIANUS +MYRIOPHYLLUM SPICATUM + CHARA COMMUNITY

Potamogeton maackianus + Myriophyllum spicatum + Chara Community was a special community type in Honghu Lake. Fish-pen farming activities and special environments were the main reasons for its formation and sustaining. This community had simple species composition, and these species are distributed evenly.The peak biomass of the community in autumn was 251 g dw m-1, and the maximun biomass was 312 g dw m-1, occuring in spring. The maximun biomass of P.maackianus was 152 g dw m-1 in autumn, M. spicatum was 45 g dw m-1 in winter,and Chara sp. was in spring, 178 g dw m-1. The main biomass of the community was concentrated in the lower part of the water column. No significant association or correlation were found among the main dominant and common species.