摘要
利用极点排序对东祁连山高寒草地植物群落进行了分析,并通过Simpson生态优势度指标对植物群落优势度进行了测定.结果表明,(1)在不同的海拔区域内,影响植物群落分布的主要环境因子不同.根据影响植物群落分布的环境因子的变化情况,可将研究地区划分为3个地段,即较低海拔地段(2 710～2 930 m),水分条件对植物群落的分布影响较为明显;中海拔地段(2 930～2 960 m),植物群落的分布主要受水,热组合状况的影响;而在较高海拔地段(2 960～3 080 m),温度条件成为限制植物群落分布的主要因素.(2)群落生态优势度与群落内植物种群数呈负相关,海拔梯度通过影响群落内的种群组成而影响群落生态优势度.不同种群生态优势度的差异则反映了群落对放牧干扰的生态响应,随退化程度的加大,种群组成由抗性弱的物种向抗性强的物种逐渐过渡.
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(27102930 m), the moisture was the major constraint for community distribution, in the medium section(29302960 m), the moisture and temperature became the dominant constraining factor,in the higher section(29603080 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.
出处
《草原与草坪》
CAS
2005年第3期42-45,共4页
Grassland and Turf
基金
国际原子能机构项目:提高作物-家畜系统生产能力(CPR/5/014)
关键词
东祁连山
高寒草地
极点排序
生态优势度
海拔
Eastern Qilian Mountains
alpine grassland
polar ordination
ecological dominance
altitude
