Effect Of Ecological Restoration On The Eutrophic And Ecological Status Of Lake Yanglan

Macroinvertebrates are important components and index for assessing the ecological status of aquatic ecosystems.In this paper,we studied the application of a restoration by means of geo-engineering,fish removal and plant transplantation in Lake Yanglan,Hubei,to explore the effect of ecological restoration on the quality of the shallow lake.This paper compared the differences in water quality and macroinvertebrate communities between the restored area and the un-restored area in Lake Yanglan,and assessed the ecological status of the lake ecosystems.The results showed that TP,TN and Chl a in water column were significantly lower in the restored area(1.12 mg/L,0.03 mg/L,3.67?g/L)than those in the un-restored area(2.41 mg/L,0.17 mg/L,67.92?g/L)except in summer.The average SD was significantly higher in the restored area(192.8 cm)than that in the un-restored area(31.7 cm)except in summer.Thirty macroinvertebrate species from12 families,4 classes and 3 phyla were found,28 species in the restored area and 19species in the un-restored area.The average density(biomass)of molluscs were 369.3ind/m~2(102.9 g/m~2)and 34.7 ind/m~2(37.2 g/m~2)in the restored and un-restored area,respectively.The average density of Tanypus chinensis was signicicantly lower in the restored area than that in the un-restored area.Biotic Index(BI)and Multimetric Macroinvertebrate Index Flanders(MMIF)based on the macroinvertebrate structure indicated that ecological status was improved in the restored area comparing the un-restored area.Our study suggests that restoration combined with transparency improvement,fish control and macrophyte re-establishment can improve water quality and the ecological status of eutrophic lakes.