Purpose

Soil nematodes play a fundamental role in regulating ecosystem carbon and nutrient cycling. It is widely recognized that soil nematode community composition is sensitive to nutrient enrichment, but the linkage between community assembly processes and functional changes under nutrient enrichment condition remains poorly understood.

Methods

We examined the compositional and functional responses and quantified the role of main community assembly processes (genus losses, genus gains, and context-dependent variations of abundance) in driving the carbon budget of soil nematode communities in response to nitrogen (N) and phosphorus (P) addition in a temperate grassland.

Results

Nitrogen and P addition significantly interacted to affect nematodes abundance, biomass, and functional variables of C cycling, in that P addition increased all the variables under ambient N condition but not under N enriched condition. Soil pH, ammonium concentration, and total phosphorus concentration played important roles in driving the variations of nematode C budgets, indicating the minor role of plant community characteristics. The enhancement of all variables following P addition was caused by the increases in the abundance of common genera (e.g. Acrobeles, Scutylenchus, and Tylencholaimus). The variation of genus richness contributed to the P-induced increases of nematode abundance but not to the increases of carbon budgets.

Conclusions

Our results uncover the linkages between community assembly processes and the abundance and C cycling function of soil nematode community under nutrient enrichment conditions. The significant interactive effects between N and P addition highlight the complexity in predicting the compositional and functional changes in soil nematode community under a scenario of multiple-nutrient enrichment.

中文翻译：

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氮磷添加交互影响温带草原土壤线虫群落的组成和碳收支

目的

土壤线虫在调节生态系统碳和养分循环方面发挥着重要作用。人们普遍认为土壤线虫群落组成对养分富集很敏感，但在养分富集条件下群落组装过程与功能变化之间的联系仍然知之甚少。

方法

我们检查了组成和功能响应，并量化了主要群落组装过程（属损失、属增加和丰度的上下文相关变化）在驱动土壤线虫群落响应氮（N）和磷的碳收支方面的作用。 P) 在温带草原中添加。

结果

氮和磷的添加显着影响线虫丰度、生物量和碳循环的功能变量，因为在环境氮条件下添加磷增加了所有变量，但在富氮条件下没有增加。土壤 pH 值、铵浓度和总磷浓度在驱动线虫 C 收支变化中起重要作用，表明植物群落特征的次要作用。添加磷后所有变量的增强是由常见属（例如Acrobeles、Scutylenchus和Tylencholaimus）的丰度增加引起的。属丰富度的变化有助于 P 诱导的线虫丰度增加，但不会导致碳收支增加。

结论

我们的结果揭示了群落组装过程与养分富集条件下土壤线虫群落的丰度和碳循环功能之间的联系。N 和 P 添加之间显着的交互作用突出了在多种养分富集情景下预测土壤线虫群落组成和功能变化的复杂性。