东祁连山高寒草地不同生境类型植物群落α及β多样性的初步研究

Primary study on α and β diversity of different habitats of alpine grassland plant community in Eastern Qilian Mountains

对东祁连山高寒草地不同生境类型(阴坡、滩地和阳坡)植物群落的α和β多样性进行了研究。结果表明,当生境由阴坡向滩地到向阳坡变化时,各种α多样性指数的变化顺序为,物种丰富度:滩地>阴坡>阳坡;均匀度和多样性指数:阴坡>阳坡>滩地。各种α多样性指数之间均呈正相关,多样性的变化主要受均匀度的影响。β多样性表现出先减小后增大的变化趋势。放牧干扰(放牧、人为不合理开发)引起生境的逐渐破碎化,使样方内微生境或资源异质性减小,样方间异质性增大,土壤湿度和日照时间适中时物种替代速率较快,从而导致β多样性增加。

The traits of α and β diversity of different habitats of alpine grassland plant community in Eastern Qilian Mountains were studied. The results showed that： from north-facing slope to south-facing slope and plain field, the species evenness and diversity index decreased; from plain field to north-facing slope and south-facing slope, richness index also decreased. The relationship of differentαdiversity indices was positive. Community diversity was mainly affected by the species evenness. β diversity indices decreased firstly, then increased from north-facing slope to south-facing slope and plain field. To a certain extent, alpine grassland habitat of Eastern Qilian Mountains was fragmented by frequent disturbance （including grazing, reclamation, etc）, which resulted in an increase of theβ diversity and species replacement rate was rapid in the condition of moderate soil moist and sunlight time.