武汉莲花湖水生植被重建的实践与启示

通过截污、控制养鱼、控藻和科学种植等措施,2~3年内,在长江中游地区水质为劣Ⅴ类的重富营养湖泊武汉小莲花湖重建了以伊乐藻(Elodea nuttallii)为优势种的沉水植物先锋群落,2004和2005年春季的沉水植被盖度分别达到98%和95%,抑制了水华的发生,改善了水质。利用冬季水位低、透明度相对高的时机种植伊乐藻、菹草(Potamogeton crispu)等这些适合冬春季生长的沉水植物是建立沉水植物先锋群落的一个有效途径。由于以伊乐藻或菹草为优势种的先锋群落不稳定,必须配备丰富物种、优化结构、增加群落稳定性等后续措施。水生植被重建初期是最脆弱的时期,某些生态因子的较大波动很容易破坏植物群落,在这一时期要尽量保持关键因子的稳定,如禁止养鱼、防止污染负荷突然增加、稳定水位是必需的。

Practice of Establishing Aquatic Vegetation in Lake Lianhuahu in Wuhan, China

Lake Lianhuahu locates in Wuhan city,which is in the middle reach of Yangtze River.It is a hypereutrophic,small and shallow lake,which consists of Lake Small Lianhuahu and Lake Large Lianhuahu.The water quality of it was worse than Class Five(water quality standard of China).Within 2-3 years pioneer submersed plant community dominanted by Elodea nuttallii was established by sewage interception,fish removing,phytoplankton controlling and transplanting submersed plants etc.in Lake Small Lianhuahu.In the springs of 2004 and 2005,the coverage of submersed vegetation was 98% and 95%,respectively.Water bloom was controlled,and the water quality was improved.To transplant Elodea nuttallii,Potamogeton crispu in winter when water level is lower and its transparence is higher than other season is an effective way to establish pioneer submersed plant community.Due to the pioneer community dominanted by submersed macrophytes E.nuttallii or P.crispu was unsteady,it is necessary to improve the structure of plant community and enhance the stability by enriching the species of established community.In the early time after the establishment,plant community was very weak that strong fluctuations of major environment factors could easily destroy the community.So it is necessary to keep the factors steady,such as forbidding breeding aquatics fish,preventing the abruptly increase of sewage load and stabilizing water level etc.