西苕溪EPT昆虫群落分布与环境因子的典范对应分析

Canonical correspondence analysis between EPT community distribution and environmental factors in Xitiaoxi River,Zhejiang,China

浙江安吉西苕溪43个样点102种EPT昆虫(蜉蝣目Ephemeroptera、翅目Plecoptera、毛翅目Trichoptera)与9个环境因子典范对应分析(CCA)表明,3种环境因子海拔、总氮、电导率对EPT群落起主要作用。CCA排序图把样点分成3个差异样点组,样点组Ⅰ与海拔高度正相关,与总氮显著负相关,属于上游溪流,撕食者占所采集撕食者总数的68.5%,水质清洁。样点组Ⅱ与电导率呈显著正相关,属于上游河面较宽的溪流,撕食者仅次于样点组Ⅰ(18.6%),水质较好。样点组Ⅲ与总氮显著正相关,总氮、总磷平均值分别为3.53和0.16,滤食者占所采集滤食者的85.01%,水质差。CCA排序图较好的说明了EPT昆虫群落的分布和环境的关系。

The relationship between 102 species of EPT（ Ephemeroptera, Plecoptera and Trichoptera） and environmental factors from 43 sampling sites in Xitiaoxi River was studied by Canonical Correspondence Analysis. The result showed that the altitude, total nitrogen, conductivity were major environmental factors correlated with EPT community. All sampling sites were plotted out 3 groups by CCA. Sites from the group Ⅰ located in the upstream of Xitiao River had significant positive correlation with altitude and negative correlation with total nitrogen. Shredders in the group Ⅰ shared the all collected shredders of 68.5%, which indicated that the water quality was clean in this group. Sites of the group Ⅱ alothough located in upstream too, their width were wider than those in group Ⅰ and positively correlated with conductivity. Shredders were only inferior to the group Ⅰ （18.6%）. Sites of the group Ⅲ located in middle reaches had significant positive correlation with total nitrogen and the average value of total nitrogen and total phosphorus were 3.53 mg/L and 0.16 mg/L respectively. The fiherers of the group Ⅲ shared the all collected fiherers of 85.01%. CCA ordination well visually demonstrated the EPT community distribution and its relationship to the environmental factors.