土壤纤毛虫群落对退牧还草生态恢复的响应——以玛曲县为例

为研究退牧还草对土壤纤毛虫群落特征的影响、退牧还草后土壤环境变化以及如何利用原生动物纤毛虫群落特征来评价退还效果的可行性,于2015年5月至2016年3月在甘肃省甘南藏族自治州玛曲县选取3个不同恢复年限的草地样点和1个未经过退牧还草对照样点,采用"非淹没培养皿法"、活体观察法和培养直接计数法对土壤纤毛虫的物种数和密度进行测定,同时测定了土壤温度、pH值、含水量、土壤孔隙度、速效钾、速效氮、速效磷、全氮、全钾、全磷和有机质含量,并分析了在生态逐渐恢复条件下,土壤纤毛虫群落特征与土壤环境因子间的相关性。研究共鉴定到纤毛虫95种,隶属9纲15目21科28属。研究发现,退牧还草样地与未退牧还草样地的土壤纤毛虫的物种分布存在明显差异:退牧还草后的3个样点间的物种相似性减小,群落组成复杂化,纤毛虫丰度、丰富度指数、均匀度指数和物种多样性指数增高。相关性分析结果表明,退牧还草后,对纤毛虫群落结构稳定性影响最主要的是土壤有机质、含水量和土壤全氮、全磷和全钾的含量,不同恢复年限样点的土壤纤毛虫群落组成差异较大。土壤纤毛虫群落对退牧还草生态恢复过程中土壤环境条件的变化有较好的响应。

Response of soil ciliates community to ecological restoration after the implementation of returning grazing to grasslands project:a case study of Maqu county, Gansu province

In order to understand the response of soil ciliate communities to the soil environmental changes afterimplementation of returning grazing to grasslands project,the community characteristics of soil ciliates at three different restoration sampling of plant sites and one control sampling site of Maqu county in Gansu provincefrom May, 2015 to March, 2016. This study was carried outusing non-flooded petri dish method, observation in vivo, and culture direct counting method. At the same time, the physic-chemical factors including soil pH, soil temperature, soil water content, soil porosity, soil available phosphorus, available potassium, available nitrogen, total nitrogen, total phosphorus, total potassium, and organic matter were investigated in different soil samples. The results showed that total 95 soil ciliate species were identified, whichbelonged to 9 classes, 15 orders, 21 families, and 28 genera.The hierarchical cluster analysis showed that there were significant differences in distribution of soil ciliate species among the soils collected from restoration sites and the control site. The similarity of species distribution in three restoration sampling sites were low, but the composition of soil ciliate communities were complex. The abundance index, richness index, evenness index, and diversity index of soil ciliate species in soil samples collected from restoration sampling sites were all higher than that in control soil samples. Correlation analysis revealed that under the condition of ecological restoration, soil water content, soil organic matter, and soil total nitrogen were main factors influencing the soil ciliate community composition. It showed that the variation of soil ciliate communities was respond well to the change of soil environmental conditions during the restoration of grazing land.