Abstract: In this study, the Illumina MiSeq high-throughput sequencing technology was applied to characterize soil microbial community structure composition and diversity variation in different patches of the alpine meadows of Kobresia humilis. The correlations between soil microorganisms and soil nutrients were analyzed. The results showed that there was no significant difference in the richness and diversity of soil fungi communities after Kobresia humilis dominated alpine meadow community was replaced by Ajania tenuifolia, Ligularia virgaurea and Pedicularis kansuensis dominated patches, but the soil bacterial community were different. The richness index of soil bacteria in Ajania tenuifolia and Ligularia virgaurea patches was significantly higher than that in Kobresia humilis meadow, while the soil bacterial richness index of Pedicularis kansuensis patches was lower than that of Kobresia humilis meadow. The change of dominant plant species and the decrease of soil nutrient content resulted in the differentiation of soil fungi trophic types. Grassland degradation reduced the abundance of saprotroph fungi and increased the symbiotroph fungi. Soil nutrient, pH, and water content had little influence on the fungi community but had greater influences on the bacterial community.

Key words: Alpine meadow, Degraded patch, Soil nutrient, Microbial diversity

摘要： 本文以矮嵩草（Kobresia humilis）高寒草甸及退化后形成的不同退化斑块群落类型草地土壤为研究对象，利用Illumina MiSeq高通量测序技术分析了不同斑块草地土壤中微生物群落结构组成和多样性变化特点，并分析了土壤微生物与土壤养分之间的相关性。结果表明：以矮嵩草为优势植物的高寒草甸群落变为以细叶亚菊（Ajania tenuifolia）、黄帚橐吾（Ligularia virgaurea）和甘肃马先蒿（Pedicularis kansuensis）为优势的群落或斑块后，土壤真菌群落丰富度和多样性未呈现出显著差异，但土壤细菌群落表现出了差别，表现为细叶亚菊和黄帚橐吾斑块土壤细菌丰富度指数显著高于矮嵩草草甸，而甘肃马先蒿斑块的低于矮嵩草高寒草甸。优势植物种类变化和土壤养分含量显著下降引起土壤真菌营养类型的分化，草地退化降低了腐生营养型真菌丰度，增加了共生营养型真菌丰度。土壤养分、pH和水分含量对真菌群落影响相对较小，对细菌群落影响相对较大。

关键词: 高寒草甸, 退化斑块, 土壤养分, 微生物多样性