赣江下游流域大型底栖动物群落结构及水质生物学评价

摘要

2009年6月(丰水期)、11月(枯水期)和2010年4月(平水期)对赣江下游流域大型底栖动物群落结构进行调查研究,共鉴定出大型底柄动物3门15科25种.结果表明,赣江下游流域大型底栖动物群落结构具有明显的时空变化.生物密度最大值( 145.9±81.8 ind./m2)出现在6月,最小值(89.6±15.9 ind./m2)出现在4月；生物量的变化则相反,最大值(90.1±25.4 g/m2),出现在4月,最小值(62.9±20.9 g/m2)出现在6月；干流的生物密度在6月、11月和4月均明显高于支流,而生物量在11月低于支流.Shannon-Wiener多样性指数(H')、Margalef丰富度指数(D)和Pielou均匀性指数(J)在6月、11月和4月的时间尺度上以及干流、支流的空间尺度上均出现明显的变化,在11月份,这3类指数均表现为最高,6月则均为最低；干流的H’和D在6月和4月均低于支流,而J在这3个时间段内则均是支流高于干流,表明支流大型底柄动物的群落结构较干流更为多样、均匀和稳定.H'和D的结果表明赣江下游流域水质均受到不同程度的污染,其中干流的污染程度较支流更为严重.%Macrozoobenthos community structure in the lower reaches of Ganjiang River was investigated in June (wet season) and November (dry season) 2009 and April (normal-water period) 2010. A total of 23 species from IS families were recorded. Results showed that temporal and spatial variations of the macrozoobenthos community structure were obvious in the lower reaches of Canjiang River. The mean maximal density (145.9 ± 81. 8 ind./m2) occurred in June while the minimum (89. 6 ± 15. 9 ind. /m2 ) appeared in April. On the contrary, the mean maximal biomass (90.1 ±25.4 g/m2) occurred in April while the minimum (62.9 ± 20.9 g/m2) appeared in June. Their mean densities in the main stream were always higher than those in branches. However, the mean biomass in main stream was lower than that in branches in November. Temporal and spatial variations of three indices (including Shannon-Wiener index, Margalef index and Pielou evenness index) were apparent. Maximal values of all the indices occurred in November while the minimum appeared in June. The Shannon-Wiener index and Margalef index in the main stream were lower than those in branches in June and April; however, the Pielou evenness index in branches was constantly higher than that in the main stream, which showed that the community structure of macrozoobenthos in branches was more diversiform, uniform, and stable than that in the main stream. According to Shannon-Wiener index and Margalef index, the lower reaches of Ganjiang River was polluted to a certain extent and the main stream was more serious.