Aims

Grazing is a key driver of plant communities and soil functions in grassland ecosystems. Soil nematodes play a vital role in soil ecological functions. The aim of this study was to explore how grazing shapes soil nematode community in different soil layers.

Methods

We investigated the composition, abundance, diversity, metabolic footprint, and food web metrics of soil nematodes over a gradient of grazing in the 0–10 cm and 10–20 cm soil layers in a meadow steppe. The relationships between nematode community structure and biotic and abiotic factors were analyzed by principal component analysis and structural equation model analysis.

Results

Light grazing increased the abundance of total soil nematodes by 18.5%. Intensive grazing decreased the carbon used in production and metabolic footprints of plant parasites, fungivores, and total soil nematodes in 0–10 cm soils. There was no difference in the carbon used in production and metabolic footprints of soil nematodes among different grazing intensities in the 10–20 cm soil layer. Soil moisture, aboveground biomass, belowground biomass and Shannon diversity of grass contributed more to changes in soil nematode composition in both soil layers. In the 0–10 cm soil layer, grazing directly and indirectly affected soil nematode diversity via soil moisture and aboveground biomass, while grazing directly affected soil nematode diversity in 10–20 cm soil layer.

Conclusions

Our results indicate that increasing soil depth can weaken the effect of grazing intensities on soil nematode fauna. Grazing affected the soil nematode community structure via different paths in different soil layers.

中文翻译：

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放牧强度对草甸草原不同土层土壤线虫群落结构和功能的影响

宗旨

放牧是草地生态系统中植物群落和土壤功能的关键驱动因素。土壤线虫在土壤生态功能中起着至关重要的作用。本研究的目的是探索放牧如何塑造不同土壤层中的土壤线虫群落。

方法

我们研究了草甸草原 0-10 厘米和 10-20 厘米土壤层中土壤线虫在放牧梯度上的组成、丰度、多样性、代谢足迹和食物网指标。通过主成分分析和结构方程模型分析，分析了线虫群落结构与生物和非生物因素的关系。

结果

轻度放牧使土壤线虫总数增加了 18.5%。集约化放牧减少了 0-10 厘米土壤中植物寄生虫、食真菌动物和总土壤线虫的生产和代谢足迹所用的碳。在 10-20 cm 土层中，不同放牧强度的土壤线虫生产和代谢足迹中使用的碳没有差异。土壤水分、地上生物量、地下生物量和草的香农多样性对两个土壤层中土壤线虫组成的变化贡献更大。在0-10 cm土层，放牧通过土壤水分和地上生物量直接和间接影响土壤线虫多样性，而放牧直接影响10-20 cm土层土壤线虫多样性。

结论

我们的结果表明，增加土壤深度可以削弱放牧强度对土壤线虫动物群的影响。放牧在不同土层通过不同途径影响土壤线虫群落结构。