芦芽山华北落叶松林不同深度土壤原生动物群落分布格局及驱动机制

Distribution patterns and driving mechanism of soil protozoan community at the different depths of Larix principis-chinensis forest in the Luya Mountain,China

为揭示亚高山森林生态系统土壤原生动物群落的构建机制,本文利用Illumina Miseq高通量测序技术,以芦芽山亚高山华北落叶松林土壤剖面的6个分层(枯枝落叶层、腐殖质层、0~10、10~20、20~40和40~80 cm)原生动物群落为研究对象,分析了其组成和多样性及驱动因素。结果表明:土壤剖面中原生动物分属于8个界21个门57个纲114个目206个科335个属。主要的优势门有5个(相对丰度>1%),优势科有10个(相对丰度>5%)。α多样性沿土壤深度的增加显著降低。主坐标分析表明,原生动物群落空间结构在土壤不同深度梯度上存在显著差异。冗余分析表明,土壤pH和含水量是决定土壤剖面原生动物群落结构的重要因子。零模型分析证实,异质选择主导了原生动物群落构建过程。分子生态网络分析显示,土壤原生动物群落的复杂性随土壤深度的增加不断降低。研究结果可为亚高山森林生态系统土壤微生物群落的构建机制研究提供数据支持。

To reveal the assembly mechanisms of soil protozoan community in subalpine forest ecosystems,we ana-lyzed the composition and diversity of protozoan communities and their drivers at the six strata(the litter profile,humus profile,0-10 cm,10-20 cm,20-40 cm and 40-80 cm)of soil profiles in subalpine Larix principis-ruppre-chtii forest in Luya Mountain using Illumina Miseq high-throughput sequencing technology.The results showed that protozoa in the soil profiles belonged to 335 genera,206 families,114 orders,57 classes,21 phyla,and 8 king-doms.There were five dominant phyla(relative abundance>1%)and 10 dominant families(relative abundance>5%).Theαdiversity decreased significantly with increasing soil depth.Results of PCoA analysis showed that the spatial composition and structure of protozoan community differed significantly across soil depths.The results of RDA analysis showed that soil pH and soil water content were important factors driving protozoan community struc-ture across soil profile.Null model analysis suggested that the heterogeneous selection dominated the processes of protozoan community assemblage.Molecular ecological network analysis revealed that the complexity of soil proto-zoan communities decreased continuously with increasing depth.These results elucidate the assembly mechanism of soil microbial community in subalpine forest ecosystem.