水体富营养化导致水生植被衰退、蓝藻水华暴发、水质恶化和水生生态系统崩溃.恢复水生植被被认为是改善受损水体水质和提高其生态系统稳定性的重要手段.本研究通过构建大型围隔,根据水生植物的耐污程度及其对水质和底质等条件的需求,选取几种适宜的水生植物在围隔内进行移栽与群落构建,并以不移栽水生植物的围隔和围隔外水体作为对照.实验期间(2011年4月至2012年6月),围隔内移栽的几种水生植物全部存活,并建立了相对稳定的群落.同时还跟踪监测了3个处理组的水质情况,结果显示,移栽水生植物的围隔内水质明显优于围隔外,与未移栽水生植物围隔相比,也有很大程度的改善,其中移栽水生植物围隔内水体的总氮、铵态氮、总磷、水下消光系数相比于围隔外水体分别低30.55%、44.09%、36.04%和42.13%,相比于未移栽水生植物围隔内水体分别低5.96%、13.40%、6.70%和7.60%,透明度分别比围隔外水体和未移栽水生植物围隔水体高74.59%和8.70%,浮游植物生物量也大大低于围隔外,而浮游动物生物量却明显高于后者.此外,实验后移栽水生植物围隔内沉积物氮、磷含量及其间隙水总氮、总磷、铵态氮浓度明显低于围隔外和未移栽水生植物围隔.研究表明,在富营养化浅水湖泊中通过建立围隔进行合理的群落配置,进而逐步恢复水生植物是完全可行的,而水生植物恢复后加强对其管理和维护至关重要.
Eutrophication induces aquatic vegetation decline, cyanobaeterial bloom, deterioration of water quality, and regime shifts in shallow lakes. Restoration of aquatic vegetation is considered as an important approach to improve water quality and en- hance ecosystem stability. In this study, we transplanted aquatic macrophytes in large enclosures with temporal aids of water treat- ments and selecting aquatic macrophyte species according to their habitat preferences. Ecological effects of the transplantation were examined by comparing water chemicals and biological indices in the enclosures with and without aquatic macrophytes, and in the open water in the lake out of the enclosures. During the experimental period (from April 2011 to June 2012), all macrophytes in the enclosure survived and built relatively stable communities. The water quality was better in the enclosure with aquatic vegetation than in area without vegetation, concentrations of total nitrogen, ammonium nitrogen, total phosphorus and light extinction in water in the vegetated enclosure decreased by 30.55% , 44.09% , 36.04% and 42.13% , respectively. In comparison, in the open wa- ter, they decreased by 5.96% , 13.40% , 6.70% and 7.60% , respectively. Secchi depth increased by 74.59% and 8.70% as compared to the open water and the enclosure without aquatic vegetation, respectively, phytoplankton biomass was lower and zoo- plankton biomass was higher in the vegetated enclosure than in the one without aquatic vegetation and in the open water. In addi- tion, aquatic vegetation tended to decrease the contents of total nitrogen and phosphorus in sediments and porewater of sediments and ammonium nitrogen concentrations in the porewater of sediments, but did not affect phosphate and nitrate in porewater of sedi-merits. The study implied that selection of eutrophication tolerant aquatic macrophytes species facilitated restoration of aquatic vege- tation and thus improve water quality in eutrophic lakes.