Abstract: A field plot sampling method was employed to investigate niches of dominant species in different resource dimensions in the lower reaches of Fenhe River, Shanxi Province of China. Niche breaths and overlaps of 20 main wetland plant species along soil pH, soil SOM, total P, total N and total K were analyzed using Shannon and Pianka formulae. The differences in niche breadth of each species in different resource dimensions show that different species have different abilities to use resources, so they have different ecological adaptability. The dominant species in the region are Rorippa globosa, Phragmites australis, Rumex dentatus, and Scirpus planiculmis, and they have higher niche breadth and adaptability to environment. Polygonum hydropiper, Artemisia lavandulaefolia, Capsella bursapastoris and Iris lactea var. chinensis have lower niche breadth. The niche overlaps of P. australis, S. planiculmis, R. globosa, R. dentatus with others were relatively larger, which illustrates that these plants make a similar use of natural resources and that there is certain competition among them.

Key words: watershed, runoff, migration, Chinese chestnut forest, nitrogen