【摘要】 本研究采用有效洞穴法确定高原鼠兔(Ochotona curzoniae)鼠洞密度(从低到高划分Ⅰ、Ⅱ、Ⅲ、Ⅳ共4个梯度),通过分析鼠洞密度与研究区裸地面积、土壤物理特征、植被结构特征的关系探究鼠兔活动对果洛藏族自治州高寒草甸土壤和植被的影响。结果表明:1) 4个梯度的有效鼠洞数量依次为每100 m~2(4±3)个(Ⅰ)、(15±2)个(Ⅱ)、(24±2)个(Ⅲ)、(37±5)个(Ⅳ);2)高寒草甸表层(0–10 cm)土壤含水量受鼠洞密度影响,在梯度之间差异显著(P <0.05),随鼠洞密度增加表层土壤含水量急剧下降,在Ⅱ、Ⅲ、Ⅳ样地基本在50%以下;3)鼠洞密度对表层土壤紧实度影响不显著(P> 0.05),仅梯度Ⅱ样地内的土壤紧实度显著高于梯度Ⅰ样地(P <0.05),其他梯度两两之间差异不显著(P> 0.05);4)有效洞口数影响样地内裸地面积(P <0.001),其中梯度Ⅳ样地裸地面积最多(占比8.75%);5)鼠洞密度对高寒草甸群落盖度影响显著(P <0.001),梯度Ⅱ、Ⅲ、Ⅳ样地的植物群落总盖度(46.55%～41.15%)显著低于梯度Ⅰ样地(98.7%); 6)鼠洞密度影响高寒草甸植被群落结构,伴随鼠洞密度的增加,优势种高山嵩草(Kobresia pygmaea)、矮嵩草(Kobresia humilis)的重要地位未改变,伴生种秦艽(Gentiana macrophylla)、垂穗披碱草(Elymus nutans)、毛果婆婆纳(Veronica eriogyne)的重要值逐渐增大,矮泽芹(Chamaesium paradoxum)、西藏堇菜(Viola kunawarensis)、矮金莲(Trollius farreri)逐步退出群落结构;7)鼠洞密度对高寒草甸群落多样性指数影响微弱(P> 0.05),不同鼠洞密度梯度样地之间植物多样性指数差异不显著。综上所述,适当的鼠兔干扰有助于改善鼠兔生境,推动高寒草甸生态系统正向演变,当高原鼠兔干扰过高时,生境质量下降迫使高寒草甸生态系统逆向演替。更多还原

【Abstract】 The density gradient of pika（Ochotona curzoniae） burrows was determined using effective number of caves method（which were expressed from low to high as levelⅠ, Ⅱ, Ⅲ and Ⅳ respectively）. To explore the effects of pika activity on the soil and vegetation of alpine meadows in Guoluo Tibetan Autonomous Prefecture, China, the relationships between the density of pika burrows and the total area of patchy bare ground, soil physical characteristics, and vegetation characteristics of alpine meadow were analyzed. The results showed that 1) The number of effective pika burrows across the four gradients was Ⅰ [（4 ± 3）·100 m^–2] < Ⅱ[（15 ± 2）·100 m^–2] < Ⅲ [（24 ± 2）·100 m^–2] < Ⅳ [（37 ± 5）·100 m^–2]. 2) The soil water content in the surface layer of the meadows（0–10 cm） was affected by the pika burrow density gradient, and the difference between the gradients was significant（P < 0.05）. With an increase in the density gradient of pika, the soil water content decreased sharply and remained below 50% in Ⅱ, Ⅲ, Ⅳ sampling plots. 3)There was no significant correlation between the pika burrow density gradient and the soil compaction of alpine meadows（P > 0.05）; only gradient Ⅱ was significantly higher than gradient Ⅰ（P < 0.05）, and the other gradients were not significantly different from each other.4)The effective burrow number had an extremely significant effect on the total area of patch bare ground（P < 0.001）, which was the largest at gradient Ⅳ（accounting for 8.75%）; 5)The mouse cave density gradient had a significant effect on the coverage of alpine meadow communities（P < 0.001）, and the total coverage of plant community at gradients Ⅱ, Ⅲ, Ⅳ（46.55%～41.15%） was significantly lower than gradientⅠ（98.7%）; 6) The pika burrow density gradient affected the plant community structure of the alpine meadows. With an increase in the pika burrow density, the populations of Gentiana macrophylla, Elymus nutans, and Veronica eriogyne gradually increased and that of Chamaesium paradoxum, Viola kunawarensis, and Trollius farreri gradually declined, although the populations of the dominant species Kobresia pygmaea and Kobresia humilis did not change. 7) There was no significant difference of plant diversity index between different gradients（P > 0.05）. In summary, properly managed pika populations can improve the habitat of the pika and promote the positive succession of the alpine meadow ecosystem. When the disturbance from pikas is too high, the resultant decline in habitat quality will cause the alpine meadow ecosystem to reverse succession.更多还原