基于分子生态学网络探究亚高山草甸退化对土壤微生物群落的影响

土壤微生物群落在草地生态系统功能中发挥着至关重要的作用，但目前尚不清楚微生物群落的分子生态网络如何响应亚高山草甸退化。以五台山4个不同退化阶段(未退化、轻度退化、中度退化和重度退化)亚高山草甸为研究对象，利用高通量测序和随机矩阵网络构建理论构建土壤微生物群落分子生态网络。探讨草地退化对亚高山草甸土壤微生物群落结构及网络的影响，不同退化程度下微生物网络结构中的关键微生物变化规律以及该过程中微生物之间的互作关系。研究结果表明，不同退化程度亚高山草甸土壤微生物(细菌、真菌和细菌-真菌)网络拓扑属性存在差异。总体上，退化增加了土壤细菌内部、真菌内部以及细菌-真菌群落间的相互作用，导致其网络结构更为复杂。未退化草甸土壤微生物网络具有较长的平均路径距离和较高的模块性，使其比退化草甸更能抵抗外界环境的变化，在应对人为干扰或者气候变化时可能具有更高的稳定性。退化草甸中的网络关键物种(模块枢纽和连接器)与未退化草甸明显不同。土壤含水量和pH与亚高山草甸土壤细菌、真菌以及整个微生物网络连通度均显著相关(P<0.05),总氮和硝氨态氮含量与土壤真菌和微生物网络连通度呈显著相关(P<0.05)。亚...

Revealing the effects of subalpine meadow degradation on soil microbial communities by molecular ecological network analyses

In this study, the molecular ecological network of soil microbial community was constructed by using high-throughput sequencing and random matrix network construction in the subalpine meadow of Wutai Mountain in four different degradation stages, i.e., non-degraded (ND), lightly degraded (LD), moderately degraded (MD), and heavily degraded (HD). To explore the effects of grassland degradation on the soil microbial community structure and network in subalpine meadow, the key microbial changes in the microbial network structure under different degradation degrees were studied, and the interactions between microorganisms during the process were investigated. The results showed that there were differences in the topological properties of soil microbial networks (bacteria, fungi and bacteria-fungi) in subalpine meadows with different degradation levels. In general, degradation increased interactions within soil bacteria, within fungi, and between bacteria-fungal communities, resulting in more complex network structures. The non-degraded meadow network had a longer average path distance and modularity than the degraded meadow networks, making it more resilient to the environmental changes with a higher stability in response to human disturbance or climate change. Key species in the degraded meadow networks (hubs and connectors) differed substantially from those in the non-degraded meadow. Soil water content and pH were significantly correlated with the network connectivity of soil bacteria, fungi and microorganisms in subalpine meadow (P<0.05), and total nitrogen and ammonium nitrogen contents were significantly correlated with the network connectivity of soil fungi and microorganisms (P<0.05). The degradation of subalpine meadow resulted in the change of the interspecific relationship of soil microorganisms and the overall ecological network of soil microorganisms.