Niche Characteristics of Potaninia mongolica Community in the Lower Reach of Shiyang River

Purpose Niche characteristics of Potaninia mongolica community in the lower reach of Shiyang River were studied to determine the species ecological adaption to the environment, which provides the scientific basis for the protection, recover and reasonable use of P.mongolica community.Method By the use of importance value, niche breadth and niche overlap, the utilization of species of P.mongolica community to resources in the lower reach of Shiyang River was analyzed to show the structure and stability of P.mongolica community.Results (1) P.mongolica was the dominant species of the community, the importance value and the niche breadth of which were significantly higher than other species.(2) In the whole community, the niche breadth from large to small was as follows:Potaninia mongolica,Salsola passerina, Allium mongolicum Regel,Zygophyllum mucronatum Maxim.,Peganum nigellastrum Bge.,Anabasis brevifolia.(3) S.passerina and Z.mucronatum Maxim.had both higher niche breadth and P.mongolica niche overlap in the whole P.mongolica community; (4) The niche overlap of the other species in the P.mongolica community was generally low, except for the individuals, among which were relatively high.Conclusion The P.mongolica community was in a relatively stable stage in the lower reach of Shiyang River.P.mongolica,S.passerina,A.mongolicum Regel,Z.mucronatum Maxim.,P.nigellastrum Bge.,A.brevifolia play critical roles in the structure of the plant community due to the wider ecological amplitude. Also, the higher the niche breadth of the speciesis, the higher niche overlap with P.mongolicais. It means that P.mongolica competes with species that requires the similar ecological environment, such as S.passerina and Z.mucronatum Maxim.