高原鼠兔刈割对青海湖流域高寒草甸植物种间关联的影响

高原鼠兔喜欢刈割茂密高寒草甸中高大植物而影响植物群落内的种间关系。采用方差比率法、χ²检验和Spearman秩相关分析相结合的方法,分析了高原鼠兔刈割行为对高山嵩草草甸植物群落种间关联的影响。结果表明:高原鼠兔刈割会促进植物群落的种间总体联结从不显著正关联变为显著负关联,降低植物群落稳定性,减少植物群落内正关联和正相关的种对数量,增加负关联、无关联和负相关的种对数量。而综合χ²检验结果、AC值和OI指数,洞口植物群落大部分种对的种间关联均不显著,种间联结程度不强。这表明χ²检验和Spearman秩相关分析能够评价小型草食动物对植物群落种间关联的影响,为全面解析高原鼠兔整体干扰驱动植物群落结构变化提供了基础信息。

Effects of clipping by plateau pika on plant interspecific associations in alpine meadows in the Qinghai Lake Region

Plateau pikas prefer to clip the tall plants in thick alpine meadow， which often alter the interspecific and intraspecific relationships among plants in the meadow. This study used the variance ratio， Chi-square （χ²） test and Spearman rank correlation coefficient to determine the effects of clipping by plateau pikas on interspecific association among plants. It was found that the clipping by plateau pikas resulted in the overall interspecific association being transformed from a non-significant positive association to a significant negative association， and decreased the stability of the plant community. The clipping by plateau pikas decreased the number of paired species with positive interspecific association and positive correlation， while it increased the number of paired species with negative interspecific association， no-interspecific association and negative correlation. The overall results of χ² testing， association coefficient （AC） value and Ochiai （OI） index showed that there were no significant interspecific associations among most species pairs in the plant community， and the interspecific associations were unstable. These results indicate that the χ² test and Spearman rank correlation coefficient can be used to quantify the effect of small herbivores on plant interspecific associations， and provide basic information on the responses of plant community structure to disturbance by plateau pika.