Restoration of Constructed Hydrophytes Community in East Lake of Wuhan and Experimental Study on Water Quality Improvement

Worldwide water eutrophication and hydrophytes declines render the collapse of water ecosystem and the deterioration of water quality. Restoration/reconstruction of aquatic macrophytes vegetation, especially submersed macrophytes vegetation is considered as an important tool for improvement of water quality and ecological restoration of the lakes. Taking enclosure of heavily eutrophic Shuiguohu of East Lake, Wuhan as a case, several steps were applied to evenly improving sediment and water quality in enclosures, and 14 autochthonic species of aquatic plants, according to respective distribution and construction in natural lakes, were chosen to replant in the Lake and construct macrophytes community. Through half a year restoration of hydrophytes vegetation, all of 14 macrophytes replanted survived and relatively steady community was established. Water quality, in particular water chroma, SD and Chl a contents in enclosures was improved after vegetation reconstruction. Compared with outside, all of nutrients other than NO3- from water and TP of sediment in enclosures decreased at different degrees, with TPw decreasing at the largest. Through PCA analysis, TPW, NH4-N, conductivity, Kd and TPS were found to affect structure of community. Main environmental gradients such as pH, COND, ORP, TPS, DO, alkalinity, Kd, PO43-, NO3-, TPW and DIC could affect dominant species in different synusia structures of constructed macrohytes community at largest. The study made the rapid shift of the Lake water from turbid state to clear state, indicating it was a feasible scheme to take a policy of turning integer to integrant parts to restore vegetation gradually through building enclosures in entrophic lakes. Enlarging the species biodiversity of aquatic plants could heighten the success rate of hydrophytes restoration.