The vegetation communities of different degraded alpine grassland inEaster Qilian Mountains were studied through polar ordination, and the Simpson dominance index was used in this paper. The results showed that: (1) the transect of the area could be divided into three sections according to the dominant environmental factors which determined the characteristics of plant communities in each section and the community distribution varied among sections. In the lower section(2 710~2 930 m), the moisture was the major constraint for community distribution, in the medium section(2 930~2 960 m), the moisture and temperature became the dominant constraining factor,in the higher section(2 960 ~ 3 080 m) , the factor of temperature was the dominant. (2) the altitudinal gradient affected the ecological dominances of plant communities by affecting the numbers of species in the communities, and the dominances of communities were related negatively to the numbers of species in the communities. The ecological dominance of different populations reflected their response to grazing disturbance. With the increase of degradation degree, the species with strong resistance were gradually replaced by those with weak resistance.
NETL
NSTL
维普
万方数据
