高原鼢鼠干扰下高寒草甸大型土壤动物多样性对环境因子的响应

Abstract

为研究高寒草甸大型土壤动物群落组成和分布对环境因子的响应，选取祁连山东段的甘肃省天祝县高原鼢鼠典型分布区域，以鼠丘密度代表干扰强度设置4个干扰区。调查各干扰区植被群落特征、土壤理化性质、大型土壤动物类群组成及其数量，采用约束性排序方法分析环境因子对大型土壤动物类群组成和分布的影响。结果表明：高原鼢鼠干扰下高寒草甸大型土壤动物优势类群为瓦娄蜗牛科、象甲科和短角亚目幼虫；极重度干扰区大型土壤动物类群的丰度、丰富度、Shannon指数显著高于重度干扰区（P<0.05）；多元回归分析表明大型土壤动物类群丰度、丰富度和Shannon指数与土壤温度呈显著负相关（P<0.05），丰富度与土壤含水量呈显著负相关（P<0.05），丰度与土壤紧实度呈显著负相关（P<0.05），丰富度和Shannon指数与植物Shannon指数呈显著负相关（P<0.05）；冗余分析和偏冗余分析表明，土壤温度、紧实度和含水量是影响高寒草甸大型土壤动物类群组成和分布的主要环境因子。;Soil fauna are important components in terrestrial ecosystems. Because soil animals are very sensitive to environment changes, they are useful indicators for soil assessing ecosystem health. In alpine meadow ecosystems, soil animals, especially invertebrates and soil dwelling microfauna are disturbed by herbivorous mammals because of their grazing, trampling, and nutrient transfer through feces and urine etc. Here, we report a study showing the effect of plateau zokor disturbance on soil fauna composition and distribution in alpine meadow in Tianzhu County in the eastern Qilian Mountain in China. We used the zokor mound density to represent its disturbance intensity. We selected four paddocks with different zokor's mounds densities to investigate the soil fauna species and habitat characteristics, including soil physical and chemical properties and plant species diversity and biomass. Multiple Regression analysis was used to determine the relationship between the soil fauna diversity and habitat characteristics. Redundancy analysis was used to assess the influence of environmental factors on soil fauna species distribution and composition. The results show that the Valloniidae, Curculionidae and Brachycera larva were the dominant soil fauna group in the study area. The abundance and richness and Shannon index of the soil animal community in the paddock with extreme disturbance intensity were significantly higher than that in the severe disturbance intensity (P<0.05). The soil fauna abundance, richness and Shannon diversity index had a significant negative correlation with soil temperature. Species richness had significantly negative correlation with soil moisture, the species abundance had significantly negative correlation with soil compaction. The Shannon diversity index for plants had significantly negative correlation with richness and Shannon diversity index of soil fauna. Furthermore, the spatial distribution of soil fauna community was significantly affected by soil temperature, compaction and soil moisture at all sites.