长江下游水生动物群落生物多样性变动趋势初探

对1990－1999年间长江下游江段生物多样性的变动趋势进行了研究，并就群落稳定性与多样性的关系进行了探讨，结果表明，物种多样性指数量大值为1．1112，最小值为0．0327，反映物种均匀度，丰盛度的指数都有不同程度的下降，而反映优势度的指数却有一定程度的上升，优势度指数最大值为1，最小值为0．34046，优势种前6位分别为杂虾，青虾，餐条，吻Qu，蛇Qu，黄颡，表明长江下游江段的生物多样性正在逐步丧失，经济鱼类数量趋减，小型野杂鱼类数量趋增。

PRELIMINARY STUDIES ON THE TREND OF CHANGE IN BIODIVERSITY OF AQUATIC ANIMAL COMMUNITY IN THE LOWER REACHES OF THE CHANGJIANG RIVER

The annual variations of bio diversity in the lower reaches of the Yangtze River during 1990-1999 were being studied,and the relationship between the bio diversity and the community stability was also being discussed by the authors. The results indicated that the maximum Shannon Wiener Diversity was 1.1112 and the minimum index was 0.0327.The species abundance and indices and evenness were declining to different degrees,while the McNaughton index heightened. The maximum McNaughton was 1 and the minimum index was 0.340457.The advantage species were shrimp, Macrobrachium nipponense,Hemiculter leucisculus, Rhinogobio typus,Saurogobio dabryi and Pseudobagrus fulvidraco from first to sixth.It showed that bio diversity in the lower reaches of the Yangtze River was declining gradually,and the quantity of fish with high economic value was declining and the quantity of small low valued fish was increasing.