在模拟条件下研究了不同密度的布氏田鼠Lasiopodomys brandtii啃食对植物群落结构及根系生物量的影响.结果表明:1)低密度鼠对植被群落结构的影响不显著,而高密度鼠可改变草地植被群落结构,植被在每100 m2 5只出现退化演替表现为优质牧草的比例降低而其他杂类草的比例增高,使之向退化草地方向演替.2)鼠类啃食促进茎叶枯萎,加速植被演替.茎叶枯萎率与鼠密度呈线性正相关.3)植被根系生物量与布氏田鼠密度关系呈现"高-低-高"的变化趋势;鼠密度为每100 m2 8只时,根系生物量降至最低.随鼠密度的增加,其须根系植物所占比例降低,其他杂草类轴根系植物比例增加.%This study explored the effect of different densities of Brandt's voles (Lasiopodomys brandtii) nibbling on plant community structure and the root biomass under simulated conditions. The results showed that: 1) the effect of low density voles on the vegetation community structure was not significant, but high density voles could change grassland vegetation community structure. The vegetation community degradation succession appeared at density of 5 voles in each 100 m2,showing the reduction in the proportion of high-quality forage and increase in the proportion of other weeds, grassland tended to degrade. 2) Nibbling Brandt's voles promoted the stems and leaves withering and accelerated the vegetation succession. There was positive correlation between the withering rate and densities of Brandt's voles. 3)Relationship between the vegetation root biomass and voles density appeared the 'high-low-high' trend, and the root biomass was the lowest at the density of 8 voles in each 100 m2. The fibrous root plants were decreased and the axial root plants such as weeds were increased.
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