应用底栖动物功能摄食群评价东苕溪下游生态系统健康状况

Application of macroinvertebrate functional groups to estimate the ecosystem health in the downstream of the East Tiaoxi River

于2013年7月(夏季),10月(秋季),12月(冬季)和2014年4月(春季)对东苕溪下游9个样点大型底栖动物功能摄食类群和营养盐状况进行了季节性调查,并采用摄食均匀度指数(Feeding Evenness Index,j_(FD))评价东苕溪下游生态系统健康状况。结果表明,该河段底栖动物摄食类群以收集者为主,且各摄食类群在季节间差异不显著(P>0.05),说明东苕溪下游小微颗粒有机物丰富。冗余分析(Redundancy Analysis,RDA)表明功能摄食群在各个季度中均与总氮关系最为密切。j_(FD)值表明东苕溪下游整体生态系统健康状况较好,但个别样点较差。这说明该河段可能存在点源污染,且生境可能出现片段化。

The seasonal investigation on the functional groups of macroinvertebrates and nutrient status was carried out at 9 sites in the downstream of the East Tiaoxi River from July 2013 to April 2014.The feeding evenness index（jFD） was used to assess the ecosystem health of the East Tiaoxi River.The results showed that the gather-collectors was the most dominant group among the functional groups of macroinvertebrates in this reach.And the functional groups of macroinvertebrates had no significant difference in four seasons（P 〉0.05）.It suggested that the small organic matters were rich in this reach.The redundancy analysis（RDA）showed that the functional feeding groups were closely related to the total nitrogen in four seasons.The jFD value indicated that the overall ecosystem health in the downstream of the East Tiaoxi River was relatively good,but the health of some samples was poor.It suggested that there might be point source pollution in this river reach,and the water habitat might be fragmented.