关键词: 沉水植物, 生态位, 群落演替

Abstract: Through field investigation, the niches of macrophyte such as Potamogeton crispus, 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 harmonic coexistence.The distribution of submerged macrophyte communities in the Jing-mi Canal results from the cooperation of niche overlap and separation.When perennial transporting water in the canal, P.crispus is due to temporal niche separation from other species and no other species to compete the space, becomes the dominant species;at the same time, Chara vertillibracteata winters in the way of dense netlike space structure and occupies quickly the spatial niche. When without transporting water in winter, Vallisneria spiralis L becomes the dominant species in soft silt and shallower water, but P.malaianus becomes the dominant species in hard silt and deeper water. The applications of Niche Theory in controlling the succession of weed community are discussed in this paper.

Key words: submerged macrophyte, niche, succession