Abstract Nematodes serve a key role in soil nutrient cycling by eating bacterial cells and fungal hyphae. However, little is known about how temperature changes affect multi-trophic interactions among host trees, root-associating fungi, and nematodes. The aim of this study was to identify abiotic and/or biotic factors that affect soil nematode communities. We constructed a pot microcosm with sandy soils from a coastal Pinus thunbergii forest. The soil-filled pots were incubated for 8 months at 20, 25, or 30 °C with or without pine seedlings. In the pots with seedlings, we measured the percentages of black, white, and brown ectomycorrhizal (ECM) formations on roots. Nematodes retrieved from the soils were morphologically identified to genus and differentiated by both trophic and community structures. The occurrence of ECM formation ranged from 85.7%–91.9%. Black ECM roots were significantly dominant at 30 °C (47.0 %), whereas white ones were significantly dominant at 20 °C (43.0 %) and 25 °C (53.0 %). The number of nematodes at 25 and 30 °C was significantly greater than that at 20 °C irrespective of the presence or absence of seedlings. In terms of trophic compositions, the relative abundance of fungivorous nematodes significantly increased from 10.4 % at 20 °C to 27.5 % at 25 °C to 44.6 % at 30 °C in the presence of pine seedlings. A non-metric multidimensional scaling scatter plot showed that the nematode communities clustered significantly among temperature treatments. Structural equation modeling indicated that nematode trophic compositions were directly regulated by temperature and the presence of pine seedlings. Our findings suggest that temperature has some cascading effects on the formation of nematode communities, and pine seedlings and associating ECM fungi contributed synergistically to the formation of their communities.

中文翻译：

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温度变化影响松树、菌根真菌和土壤线虫在微观实验中的多营养相互作用

摘要 线虫通过吃细菌细胞和真菌菌丝在土壤养分循环中发挥关键作用。然而，人们对温度变化如何影响寄主树木、根相关真菌和线虫之间的多营养相互作用知之甚少。本研究的目的是确定影响土壤线虫群落的非生物和/或生物因素。我们用来自沿海松柏林的沙质土壤构建了一个盆栽缩影。在 20、25 或 30°C 下，无论是否有松树幼苗，都将充满土壤的盆培养 8 个月。在装有幼苗的盆中，我们测量了根部黑色、白色和棕色外生菌根 (ECM) 形成的百分比。从土壤中回收的线虫在形态上被鉴定为属，并通过营养和群落结构进行区分。ECM 形成的发生范围为 85。7%–91.9%。黑色 ECM 根在 30 °C (47.0 %) 时显着占优势，而白色根在 20 °C (43.0 %) 和 25 °C (53.0 %) 时显着占优势。无论有无幼苗，25℃和30℃时的线虫数量均显着大于20℃时的线虫数量。在营养成分方面，在松苗存在的情况下，食真菌线虫的相对丰度从 20°C 时的 10.4% 显着增加到 25°C 时的 27.5% 到 30°C 时的 44.6%。非度量多维标度散点图显示线虫群落在温度处理之间显着聚集。结构方程模型表明线虫的营养成分直接受温度和松树幼苗的调节。