Substantial evidence suggests that biodiversity can stabilize ecosystem function, but how it does this is less clear. In very general terms, the hypothesis is that biodiversity stabilizes function because having more species increases the role of compensatory dynamics, which occur when species in a community show different responses to the environment. Here, we focus on two forms of compensatory dynamics, cross‐scale redundancy (CSR) and response diversity (RD). CSR occurs when species respond to a disturbance at different scales such that scale‐specific disturbances do not negatively affect all species. RD occurs when species contributing to the same function show different responses to an environmental change. We developed a new analytical approach that can compare the strength of CSR and RD in the same dataset and used it to study native bee pollination of blueberry at 16 farms that varied in surrounding agricultural land use. We then asked whether CSR and RD among bee species are associated with the stability of blueberry pollination. Although CSR and RD were both present, only RD was associated with higher stability of pollination. Furthermore, the effects of RD on stability were due to a single widespread species, Andrena bradleyi, that is a specialist on blueberry and, unlike other bee species, was highly abundant at farms surrounded by intensive blueberry agriculture. Thus, the stabilizing effect we observed was attributable to an “identity effect” more than to species richness per se. Our results demonstrate how CSR and RD can be empirically measured and compared and highlight how the theoretical expectations of the biodiversity–ecosystem functioning field are not always upheld when confronted with real‐world data.

中文翻译：

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优势物种通过响应多样性来稳定授粉服务，但不是跨尺度冗余


大量证据表明，生物多样性可以稳定生态系统的功能，但尚不清楚它是如何做到这一点的。一般来说，假设是生物多样性稳定了功能，因为拥有更多的物种会增加补偿动力学的作用，当群落中的物种对环境表现出不同的反应时，就会发生补偿性动力学。在这里，我们关注两种形式的补偿动力学，即跨尺度冗余 （CSR） 和响应多样性 （RD）。当物种对不同尺度的干扰做出反应时，就会发生 CSR，以至于尺度特异性干扰不会对所有物种产生负面影响。当有助于相同功能的物种对环境变化表现出不同的反应时，就会发生 RD。我们开发了一种新的分析方法，可以比较同一数据集中 CSR 和 RD 的强度，并使用它来研究周围农业用地用途不同的 16 个农场的蓝莓原生蜜蜂授粉。然后，我们询问蜜蜂物种之间的 CSR 和 RD 是否与蓝莓授粉的稳定性相关。尽管 CSR 和 RD 都存在，但只有 RD 与较高的授粉稳定性相关。此外，RD 对稳定性的影响是由于一个广泛分布的物种 Andrena bradleyi，它是蓝莓专家，与其他蜜蜂物种不同，它在被集约化蓝莓农业包围的农场中数量众多。因此，我们观察到的稳定效应更多地归因于“身份效应”，而不是物种丰富度本身。我们的结果展示了如何通过实证测量和比较 CSR 和 RD，并强调了在面对真实世界数据时，生物多样性-生态系统功能领域的理论期望并不总是得到支持。