从上海市凤眼莲的生活史特征与繁殖策略探讨其控制对策

凤眼莲是上海地区水体中危害最严重的外来人侵种之一。通过对上海地区凤眼莲种群的连续监测，探究其生活史特征及其繁殖策略，结果表明，1）每年3～5月为凤眼莲的萌芽阶段，7月下旬为凤眼莲爆发起始时期，8～12月为凤眼莲爆发的高峰期，12月下旬凤眼莲开始枯萎死亡。但其腋芽能够存活越冬，是来年凤眼莲爆发的种源。2）上海地区凤眼莲主要以无性繁殖为主。导致该结果的内因是凤眼莲具有高的克隆生长潜力，外因是上海市水体富营养化严重。3）河道内其它水生植物的广泛分布是凤眼莲固着生长的主要机制，这些植物主要为：喜旱莲子草、菰、芦苇、牛筋草和千金子等。有鉴于此，根据上海市凤眼莲的生活史特征和繁殖策略，提出其综合防治对策为：1）最佳的打捞时期为12月至翌年6月，以去处种源为目标；2）清理河道内及堤岸上的水生杂草；3）开展生物防治的研究；4）加强与周边省份的协调合作。

Control methods of Eichhornia crassipes in Shanghai based on its life cycle and reproduce strategy

Eichhornia crassipes (water hyacinth) is a notorious invasive species in Shanghai, the biggest city of China. In order to uncover the life cycle of E. crassipes and its reproduce strategy, we carried out the natural investigation from July 2002 to December 2003. Results showed that the shoots of E. crassipes appeared in March, and the populations of E. crassipes burst out from August till December, then the plants damped off and died. But the shoots under-arm could survive through the winter which protected by their own-leaves or other plants. Populations of E. crassipes in Shanghai reproduced by asexual reproduction mostly. The population fluctuation of E. crassipes was influenced by other hydrophytes which living together with E. crassipes. In our opinion, the effective control methods are the synthesize managements, including the harmony with Jiangsu province and Zhejiang province; controlling other hydrophytes; decreasing the pollutant in the river; and salvaging the clones of water hyacinth from December to June.