Abstract: This paper studied effects of various plateau pika population sizes in different levels of degraded grasslands , planted grassland and weeds control treatment , and analyzed the response of plateau pikas to environmental changes.The results indicated that plateau pika population sizes increased with the degrees of grassland deterioration1 Population sizes of plateau pika were relative low in heavily degraded grassland because of limited food resource. Population sizes show significant differences among different treatments of non-degraded grassland (NDG) , lightly degraded grassland (LDG) , moderately degraded grassland (MDG) , and heavily degraded grassland (HDG) , i.e. , ( t_{NDG- LDG} = 25.369 7 , t_{NDG- MDG} = 25.55 , t_{NDG- HDG} = 36.406 0 , t_{LDG- MDG} =23.279 4 , t_{LDG- HDG} = 14.343 9 , and t_{MDG- HDG} = 20.178 5 , df = 3 , P < 0.001) . Areas destroyed by plateau pikas had significantly positive correlation with area per hollow ( F = 220.46 , df = 3 , P < 0.001) . Before grassland became heavily degraded grassland , the degree of degradation aggravate when population sizes increased. The changes of the spatial structure of plant community could cause the changes of population sizes of plateau pika. Population sizes were decreased when height and coverage of plant community were reduced.

Key words: Plateau pika ( Ochotona curzoniae), Kobresia pygmaea meadow, Prevention and control

摘要： 1997～2000 年在青海省果洛州达日县, 通过测定不同程度退化草地、人工草地和除杂草地中高原鼠兔种群数量的变化以及对草地的破坏程度, 分析了草地植物群落变化对高原鼠兔种群数量的影响。结果表明: 随草地退化程度的加重, 高原鼠兔种群数量相应升高, 重度退化草地中高原鼠兔种群数量降低, 是由食物资源不足引起。不同程度退化草地之间高原鼠兔种群数量差异极显著( t_{未退化与轻度}= 25.369 7 , t_{未退化与中度}= 25.55 ,t_{未退化与重度}= 36.406 0 , t_{轻度与中度}= 23.279 4 , t_{轻度与重度}= 14.343 9 , t_{中度与重度}= 20.178 5 , df = 3 , p < 0.001) 。高原鼠兔对草地的破坏面积与平均单坑面积呈显著的相关关系( F = 220146 , df = 3 , P < 0.001) 。在草地达到重度退化以前, 高原鼠兔的种群密度升高, 对草地的危害则加重。草地植物群落空间结构的变化直接影响高原鼠兔的种群数量, 当植物群落高度增加时, 其种群数量开始减少, 反之则增加。

关键词: 高原鼠兔, 小嵩草草甸, 防治