Background

Precipitation regimes in arid and semi-arid regions are exhibiting a trend of increase in rainfall intensity but reduction in frequency, affecting soil communities and ecosystem functions. Soil nematodes are essential components of soil communities, partaking in multiple energy channels and underpinning various crucial ecosystem functions. Understanding the impact of precipitation regime changes on energy fluxes within soil nematode food webs has a decisive impact on ecosystem function under global climate change.

Methods

This study conducted a long-term field experiment established in 2012 to simulate precipitation regime changes (the total precipitation added was 80 mm unchanged, but the size and frequency of applied precipitation events were varied) in a semi-arid grassland of Inner Mongolia. We quantified the metabolism and energetic structure of soil nematodes. We further investigated the responses of metabolic rate of trophic groups and energy fluxes within soil nematode to changes in precipitation regime, and how such changes in nematode energy dynamics affect ecosystem multifunctionality (EMF).

Results

We found that heavy precipitation intensity increased the metabolic rates and energy fluxes of all trophic groups, and the EMF index was maximized. The EMF values were positively correlated with the metabolic rates and energy fluxes of bacterivores and omnivores/predators.

Conclusions

These results suggest that a shift toward higher-intensity and lower-frequency precipitation events could lead to an increase in energy fluxes within soil nematode food webs, thereby enhancing their contributions to EMF. These findings provide insights into the role of energy dynamics in affecting EMF under various scenarios of precipitation pattern changes.

中文翻译：

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温带草原土壤线虫食物网能量动力学改变对多功能性的改变

 背景

干旱和半干旱地区的降水状况呈现出降雨强度增加但频率降低的趋势，影响了土壤群落和生态系统功能。土壤线虫是土壤群落的重要组成部分，参与多种能量通道并支撑着各种关键的生态系统功能。了解降水状况变化对土壤线虫食物网内能量通量的影响，对全球气候变化下的生态系统功能具有决定性影响。

 方法

本研究进行了一项于 2012 年建立的长期野外试验，模拟了内蒙古半干旱草原降水状况的变化 （总增加的降水量没有变化，但施加的降水事件的大小和频率各不相同）。我们量化了土壤线虫的新陈代谢和能量结构。我们进一步研究了土壤线虫体内营养群代谢速率和能量通量对降水状态变化的响应，以及线虫能量动力学的这种变化如何影响生态系统多功能性 （EMF）。

 结果

我们发现，强降水强度增加了所有营养类群的代谢速率和能量通量，并且 EMF 指数最大化。EMF 值与食细菌动物和杂食动物/捕食者的代谢率和能量通量呈正相关。

 结论

这些结果表明，向高强度和低频率降水事件的转变可能导致土壤线虫食物网内的能量通量增加，从而增强它们对 EMF 的贡献。这些发现为能量动力学在各种降水模式变化情景下影响 EMF 的作用提供了见解。