The size, frequency, and timing of precipitation events are predicted to become more variable worldwide. Despite these predictions, the importance of changes in precipitation in driving multiple above‐ and belowground ecosystem attributes simultaneously remains largely underexplored. Here, we carried out 3 yr of rainfall manipulations at the DRI‐Grass facility, located in a mesic grassland in eastern Australia. Treatments were implemented through automated water reapplication and included +50% and −50% amount, reduced frequency of events, and an extreme summer drought. We evaluated the spatiotemporal responses of multiple ecosystem attributes including microbial biomass, community composition and activity, soil nutrient content and availability, and plant nutritional status to altered rainfall regimes. We found that changing precipitation patterns resulted in multiple direct and indirect changes in microbial communities and soil and plant nutrient content. Main results included greater availability of soil macronutrients and reduced availability of micronutrients under drought, and taxon‐specific changes in the composition of soil microbial communities in response to altered rainfall. Moreover, using structural equation modeling, we showed that, in summer 2015, plant macronutrient contents, a widely used ecological indicator of pasture quality, were simultaneously explained by greater soil nutrient availability and the structure of soil microbial communities, and significantly reduced by lower rainfall. Plant micronutrients were also reduced by lower rainfall and explained by changes in microbial attributes. Despite treatment effects on many of the soil, microbial, and plant variables analyzed across the 3 yr of study, many of these ecosystem attributes varied greatly across sampling events. This resulted in many significant interactions between the rainfall treatments and experimental duration, suggesting complex system‐level responses to changing rainfall in our grassland, and a high natural buffering capacity of the ecosystem to varying rainfall conditions. Some interactions manifested as changes in the coefficient of variation of ecosystem attributes, particularly in response to changes in the timing of precipitation events and the extreme summer drought. Finally, we posit that a detailed understanding of plant–soil–microbial interactions, and the role of climate in modifying these linkages, will be key for adapting the sustainability of grasslands to a future that will be shaped by climate change.

中文翻译：

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降雨改变后澳大利亚草原土壤微生物群落，功能和植物营养之间的联系

预计全球范围内降水事件的大小，频率和时间会变得更加可变。尽管有这些预测，但降水变化在同时驱动多种地上和地下生态系统属性方面的重要性仍未得到充分探索。在这里，我们在位于澳大利亚东部一片草原上的DRI-Grass工厂进行了3年的降雨处理。通过自动补水实施处理，处理量包括+ 50％和-50％，事件发生频率降低，以及夏季极端干旱。我们评估了多种生态系统属性的时空响应，包括微生物生物量，群落组成和活动，土壤养分含量和可利用性以及植物营养状况对降雨状况的变化。我们发现，不断变化的降水模式导致微生物群落以及土壤和植物养分含量的多种直接和间接变化。主要结果包括干旱条件下土壤大量营养素的供应量增加，微量营养素的供应量下降，以及因降雨变化而引起的土壤微生物群落组成的分类群特异性变化。此外，利用结构方程模型，我们发现，2015年夏季，广泛使用的牧草质量生态指标植物常量营养素含量，同时被解释为土壤养分利用率和土壤微生物群落结构增加，而降雨减少则显着减少。降雨减少也减少了植物微量营养素，并且可以通过微生物属性的变化来解释。尽管在研究的3年中分析了许多土壤，微生物和植物变量对处理的影响，但在采样事件中，许多这些生态系统属性差异很大。这导致了降雨处理和实验持续时间之间的许多重大相互作用，这表明我们对草原降雨变化的复杂系统级响应，以及生态系统对降雨条件变化的自然缓冲能力很高。一些相互作用表现为生态系统属性变异系数的变化，特别是对降水事件时间和夏季极端干旱时间变化的响应。最后，我们假设对植物-土壤-微生物的相互作用以及气候在改变这些联系方面的作用有详细的了解，