Odonata Aquatic Insects as Bioindicators in Water Quality Evaluation of Dianchi Lake Riparian Wetland

Objective To find out the indication roles of Odonata aquatic insects in Dianchi Lake riparian wetland water quality evaluation.

Method The physicochemical variables were measured and Odonata aquatic insect community structure was surveyed at 12 sites in Haidongwan riparian wetland, the entrance of Dianchi Lake. The water quality levels were classified; The IndVals and community feature indices were calculated and compared. The correlation between the aquatic insect community structure, the physicochemical variables and water quality levels; the aquatic insect community structure and the physicochemical variables were analyzed by Pearson correlation analysis.

Result The species composition of aquatic insects at different water quality levels was different. Megalestes was the indicator of level Ⅱ. Copera and Ischnura were the indicators of level Ⅲ. There are no indicators of level Ⅳ and Ⅴ. For the community feature indices, Simpson dominance index and Shannon-Wiener diversity index decreased with the decrease of water quality levels. The water quality levels were positively correlated with total phosphorus and chemical oxygen demand, and negatively correlated with dissolved oxygen. Moreover, the Simpson dominance index, Shannon-Wiener diversity index of Odonata aquatic insects showed significant positive correlation with dissolved oxygen, and significant negative correlation with the total phosphorus.

Conclusion Odonata aquatic insect species and community structure characteristics can be used to indicate the water quality of Haidongwan wetland water quality so as to indirectly reflect the water quality of Dianchi Lake.