Many global changes take the form of resource enhancements that have potential to transform multiple aspects of ecosystems from slower to faster cycling, including a suite of both above- and belowground variables. We developed a novel analytic approach to measure integrated ecosystem responses to resource-enhancing global changes, and how such whole ecosystem slow-to-fast transitions are linked to diversity and exotic invasions in real-world ecosystems. We asked how 5-year experimental rainfall and nutrient enhancements in a natural grassland system affected 16 ecosystem functions, pools and stoichiometry variables considered to indicate slow versus fast cycling. We combined these metrics into a novel index we termed "slow-fast multifunctionality" and assessed its relationship to plant community diversity and exotic plant dominance. Nutrient and rainfall addition interacted to affect average slow-fast multifunctionality. Nutrient addition alone pushed the system towards faster cycling, but this effect weakened with the joint addition of rainfall and nutrients. Variables associated with soil nutrient pools and cycling most strongly contributed to this antagonistic interaction. Nutrient and water addition together, respectively, had additive or synergistic effects on plant trait composition and productivity, demonstrating divergence of above- and belowground ecosystem responses. Our novel metric of faster cycling was strongly associated with decreased plant species richness and increased exotic species dominance. These results demonstrate the breadth of interacting community and ecosystem changes that ensue when resource limitation is relaxed.

中文翻译：

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资源增强的全球变化推动整个生态系统转向更快的循环但降低多样性

许多全球变化都以资源增强的形式出现，这些变化有可能将生态系统的多个方面从较慢的循环转变为较快的循环，包括一套地上和地下变量。我们开发了一种新的分析方法来衡量综合生态系统对资源增强型全球变化的反应，以及整个生态系统从慢到快的转变如何与现实世界生态系统中的多样性和外来入侵联系起来。我们询问了天然草地系统中 5 年的实验降雨和养分增强如何影响 16 种生态系统功能、水池和化学计量变量，这些变量被认为表明慢循环与快循环。我们将这些指标组合成一个我们称为“慢-快多功能性”的新指数，并评估其与植物群落多样性和外来植物优势的关系。养分和降雨添加相互作用影响平均慢-快多功能性。单独添加养分将系统推向更快的循环，但这种效果随着降雨和养分的联合添加而减弱。与土壤养分库和循环相关的变量对这种对抗性相互作用的贡献最大。养分和水的添加分别对植物性状组成和生产力具有相加或协同效应，表明地上和地下生态系统响应存在差异。我们关于更快循环的新指标与植物物种丰富度的减少和外来物种优势的增加密切相关。这些结果表明，当资源限制放松时，相互作用的社区和生态系统变化的广度。