Losses and gains in species diversity affect ecological stability1–7 and the sustainability of ecosystem functions and services8–13. Experiments and models have revealed positive, negative and no effects of diversity on individual components of stability, such as temporal variability, resistance and resilience2,3,6,11,12,14. How these stability components covary remains poorly understood15. Similarly, the effects of diversity on overall ecosystem stability16, which is conceptually akin to ecosystem multifunctionality17,18, remain unknown. Here we studied communities of aquatic ciliates to understand how temporal variability, resistance and overall ecosystem stability responded to diversity (that is, species richness) in a large experiment involving 690 micro-ecosystems sampled 19 times over 40 days, resulting in 12,939 samplings. Species richness increased temporal stability but decreased resistance to warming. Thus, two stability components covaried negatively along the diversity gradient. Previous biodiversity manipulation studies rarely reported such negative covariation despite general predictions of the negative effects of diversity on individual stability components3. Integrating our findings with the ecosystem multifunctionality concept revealed hump- and U-shaped effects of diversity on overall ecosystem stability. That is, biodiversity can increase overall ecosystem stability when biodiversity is low, and decrease it when biodiversity is high, or the opposite with a U-shaped relationship. The effects of diversity on ecosystem multifunctionality would also be hump- or U-shaped if diversity had positive effects on some functions and negative effects on others. Linking the ecosystem multifunctionality concept and ecosystem stability can transform the perceived effects of diversity on ecological stability and may help to translate this science into policy-relevant information.Species richness was found to increase temporal stability but decrease resistance to warming in an experiment involving 690 micro-ecosystems consisting of 1 to 6 species of bacterivorous ciliates that were sampled over 40 days.

中文翻译：

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生物多样性增加和降低生态系统稳定性

物种多样性的损失和增加会影响生态稳定性 1-7 以及生态系统功能和服务的可持续性 8-13。实验和模型揭示了多样性对稳定性的各个组成部分的积极、消极和无影响，例如时间可变性、抵抗力和弹性2,3,6,11,12,14。这些稳定性成分如何共变仍然知之甚少15。同样，多样性对整体生态系统稳定性 16 的影响，在概念上类似于生态系统多功能性 17, 18，仍然未知。在这里，我们研究了水生纤毛虫群落，以了解在一项涉及 690 个微生态系统的大型实验中，时间可变性、抵抗力和整体生态系统稳定性如何对多样性（即物种丰富度）做出反应，该实验涉及 690 个微生态系统，在 40 天内采样 19 次，产生 12,939 个样本。物种丰富度增加了时间稳定性，但降低了对变暖的抵抗力。因此，两个稳定性分量沿多样性梯度负协变。尽管普遍预测多样性对个体稳定性组件的负面影响，但以前的生物多样性操纵研究很少报告这种负面协变。将我们的发现与生态系统多功能性概念相结合，揭示了多样性对整体生态系统稳定性的驼峰和 U 型影响。即生物多样性可以在生物多样性低时提高整体生态系统稳定性，在生物多样性高时降低整体稳定性，或呈U型关系相反。如果多样性对某些功能有积极影响而对其他功能有消极影响，那么多样性对生态系统多功能性的影响也将呈驼峰或 U 型。