京密引水渠常见沉水植物的生态位和群落演替

生态位是生物(个体、种群或群落)对生态环境条件适应性的总和。通过野外调查，研究菹草、轮苞轮藻、马来眼子菜、苦草等沉水植物的生态位。生态位的重叠导致物种间的竞争与排斥，生态位的分离，导致物种间的协调平衡。引水渠沉水植物群落状况是生态位的重叠和分离共同作用的结果。在常年输水条件下，菹草以时间生态位分离，空间无竞争对手而占据优势；轮苞轮藻以群落的致密絮状结构越冬，优先占领空间生态位；在冬季不输水的条件下，苦草以温度生态位在淤泥、浅水区占优势；马来眼子菜以生长生态位在硬泥质、深水水域占优势。并讨论了生态位理论在水草群落演替控制中的应用。

Study on Niche and Community Succession of Submerged Macrophyte in Jing-Mi Canal, Beijing

Through field investigation,the niches of macrophyte such as Potamogeton cris pus,Chara vertillibracteata,P.malaianus,Vallisneria spiralis have been carried on in Jing mi Canal.Niche overlap among species causes species competition and exclusion among species,and niche separation among species causes species harmo nic coexistence.The distribution of submerged macrophyte communities in the Jin g mi Canal results from the cooperation of niche overlap and separation.When perennial transporting water in the canal, P.crispus is due to temporal nich e separation from other species and no other species to compete the space,become s the dominant species;at the same time, Chara vertillibracteata winters in t he way of dense netlike space structure and occupies quickly the spatial niche.W hen without transporting water in winter, Vallisneria spiralis L becomes the dominant species in soft silt and shallower water,but P.malaianus becomes t he dominant species in hard silt and deeper water.The applications of Niche Theo ry in controlling the succession of weed community are discussed in this paper.