拉萨温性草原土壤原生动物群落对不同放牧强度的响应

Response of Soil Protozoa Community to Different Grazing Intensities in Lhasa Valley Grassland

探究土壤原生动物对拉萨河谷温性草原不同放牧强度的响应,可以动态监测草原生态系统的环境变化,为保护青藏高原草原生态环境提供科学依据。本研究选取5年围封的温性草原进行为期3年的放牧试验,于2018年9月采取不同放牧强度下的土壤样品进行土壤原生动物培养和鉴定(非淹没培养法、活体观察法)。结果表明:供试样地共鉴定出土壤原生动物46属,隶属于2门、12纲、21目和36科;不同放牧强度下的土壤原生动物主要类群为旋毛纲(Spirotrichea);不同放牧强度下土壤原生动物多样性指数(H、E、C、M)无显著差异(P>0.05);Jaccard相似性指数在极不相似到中等不相似之间;样地B3(禁牧)单独聚为一类,说明其空间异质性较大;全氮是影响土壤原生动物分布的主要环境因子,土壤湿度、速效钾、电导率等环境因子共同影响不同放牧强度下土壤原生动物物种组成和分布。

In this study,a 3-year experiment with different grazing intensities was conducted in a temperate grassland enclosed for 5 years in Lhasa Valley grassland in order to provide scientific evidence to conservation of grassland ecological environment on the Qinghai-Tibet Plateau.Soil samples were collected and soil protozoa were cultured and identified by non-submerged culture and in vivo observation in September of 2018.The results showed that a total of 46 soil protozoa genera were identified,belonging to 36 families,21 orders,12 classes and 2 phyla.The main group of soil protozoa was Spirotrichea under different grazing intensities.The diversity indexes(H,E,C,M)of soil protozoa had no significant difference under different grazing intensities(P>0.05),Jaccard similarity index ranged from extremely dissimilar to moderately dissimilar.Plot B3(ban grazing)was clustered into a single category,indicating that the spatial heterogeneity was large.TN was the main environmental factor affecting the distribution of soil protozoa,the combined effects of soil water content(SWC),rapid available potassium(RAK),EC and other environmental factors affected the species composition and distribution of soil protozoa under different grazing intensities.