大亚湾大型底栖动物物种多样性现状

利用2004年3月、5月、9月和12月的大型底栖动物定量采样数据，对大亚湾大型底栖动物的物种多样性进行研究。结果表明，因人类活动影响的加剧，目前大型底栖动物多样性明显低于历史水平。2004年大亚湾海域内共出现79种（类）大型底栖动物，全海域均匀度（J）、丰富度（D）和Shannon—Wiener指数（H’）均值分别为1．17、0．74和2．06。各多样性指数的季节变化较小，不存在显著差异（P〉0．05）。多样性水平以冬季〈春季〈夏季〈秋季。大亚湾明显的干、湿季变化对大型底栖动物多样性有所影响，湿季多样性水平高于干季。湾口海域大型底栖动物多样性水平较高，因湾顶和湾中部海域内小鳞帘蛤Veremolpamicra和粗帝汶蛤Timocleascabra极强的优势地位，导致湾顶和湾中部海域多样性水平较低。水温升高而引发的小鳞帘蛤和粗帝汶蛤丰度的变化，造成了湾顶和湾中部海域大型底栖动物多样性水平的季节变化。

Study on species diversity of macrobenthos in Daya Bay, South China Sea

Based on the data of macrobenthos collected from the surveys of 4 cruises which were conducted in Mar. , May, Sep. , Dec. 2004 in Daya Bay, South China Sea, the species diversity of macrohenthos was studied. The results showed that nowadays the level of species diversity was lower than that in 1987 due to the more impacts of human activities on the bay since then. In 2004, the number of macrobenthos species was 79. The mean of richness index （J）, evenness index （D） and Shannon-Wiener index （H＇） were 1.17, 0. 74 and 2. 06, respectively. The seasonal changes of each diversity index was small, without significant different （ P 〉 0. 05 ）. The level of species diversity showed the trend of winter 〈 spring 〈 summer 〈 autumn. It has been found that the distinct change of dry and wet season, the species diversity in wet season was higher than those in dry season. The species diversity of maerobenthos in outer Bay was the highest among other areas. The dominant species of Veremolpa micra and Timoclea scabra were so abundant that the species diversity of macrobenthos in center Bay and inner Bay were low. The seasonal change of the species diversity of macrobenthos in center Bay and inner Bay was caused by the change of the abundance of V. micra and T. scabra. Then the abundance of V. micra and T. scabra fluctuated with the water temperature directly.