年楚河流域沙棘林土壤纤毛虫群落特征及环境因子相关性

Soil ciliate community structure and relationship with environmental factors in sea buckthorn forest in Nianchu river basin

沙棘林具有重要的经济、生态和社会效益,对于青藏高原生态环境安全维护具有重要的作用,而土壤纤毛虫可以作为沙棘林生态系统动态变化的指示生物。于2020年5月(春)、8月(夏)、10月(秋),根据年楚河流域沙棘林的分布特征选取了5个典型的天然沙棘林作为样地,共获得75个土壤样品。采用“非淹没培养皿法”和“活体观察法”对土壤纤毛虫进行培养鉴定,对于难以辨认的物种采用“蛋白银染色”进一步确认。研究共鉴定出土壤纤毛虫90种,隶属于10纲、20目、30科、47属,其中优势类群为散毛目(Sporadotrichia),共计15种,占总物种数的16.67%;单因素方差分析结果显示,年楚河流域沙棘林土壤纤毛虫多样性指数在季节间存在差异(P<0.05);共发生网络显示春季年楚河流域沙棘林物种间的相互作用更为复杂;优势种生态位重叠值较高(Oik>0.6)有28对,占总对数的77.78%,说明优势种种间竞争激烈;mantel分析结果显示pH、RAK是影响年楚河流域沙棘林土壤纤毛虫多样性指数的主要因子;三个季节冗余分析(RDA)显示含水量(SWC)、有效磷(AP)、全氮(TN)、速效钾(RAK)是影响年楚河流域沙棘林土壤纤毛虫物种分布的环境因子。该研究结果有助于了解年楚河流域沙棘林生态系统变化,为青藏高原生态环境保护和可持续发展提供基础数据支持。

Sea buckthorn forest has important economic,ecological and social benefits,and plays an important role in the ecological and environmental security of the Qinghai-Tibet Plateau.Soil ciliates can be used as indicators of the dynamic changes of sea buckthorn forest ecosystem.In May(spring),August(summer)and October(autumn)of 2020,five typical natural sea buckthorn forests in the Nianchu river basin were selected as sample sites according to the distribution characteristics of sea buckthorn forests,and a total of 75 soil samples were obtained.Culture and identification of soil ciliates were performed by"non-submerged petri dish method"and"in vivo observation method",and protein silver staining was used to further confirm the species that were difficult to identify.A total of 90 species of soil ciliates were identified in this study,belonging to 47 genera,30 families,20 orders,and 10 classes.The dominant group was Sporadotrichia(15 species),accounting for 16.67%of the total species.The results of one-way ANOVA showed that the diversity index of soil ciliate in sea buckthorn forest was different between seasons(P<0.05).The cooccurrence network showed that the soil ciliate species interaction in sea buckthorn forest was more complex in spring.There were 28 pairs of dominant species with high niche overlap(Oik>0.6),accounting for 77.78%of the total logarithm,indicating fierce competition among dominant species.Mantel analysis showed that pH and available potassium were the main factors affecting soil ciliate diversity index in sea buckthorn forest.Redundancy analysis(RDA)showed that soil water content,available phosphorus,total nitrogen and available potassium were the environmental factors affecting the distribution of ciliate species in the soil of sea buckthorn forest in the Nianchu river basin.The results of this study are helpful to understand the changes of sea buckthorn forest ecosystem in the Nianchu river basin,and provide basic data support for ecological and environmental protection and sustainable development of the Qinghai-Tibet Plateau.