Abstract Ecological theory states that the resilience of ecosystem functions to environmental disturbance depends on the biodiversity that underpins them, but field validations of this are rare. In this study, we explore how shifts in the composition of an intertidal macrofauna assemblage following organic matter enrichment affect the representation and composition of functional groups (FG) underpinning sandflat biogeochemistry and stability. Slow-release organic fertiliser was incorporated into experimental plots (1.44 m2) in a gradient study design (treatments ranged from 0 to 2250 g dw m−2). Macrofaunal communities were sampled 70 d later, after changes in sediment conditions associated with organic matter decomposition (hypoxia, acidification and increased concentrations of reduced solutes) had taken effect. Taxa-specific sensitivities to organic enrichment resulted in a significant diversity of responses within FGs, and density compensation was observed in one FG as a result of the disturbance; this enabled FGs to persist even at high levels of enrichment. Despite this, total community abundance decreased by 80% between low and high levels of enrichment and substantial declines in the abundance of dominant taxa reduced the viability of several FGs. Our study demonstrates a density-dependent relationship between macrofaunal biodiversity and ecosystem function, as declines in benthic primary production and nutrient recycling were significantly correlated with decreases in the abundance of key taxa. Despite the occurrence of stabilising mechanisms that provided resilience to FGs, taxonomic diversity was crucial for maintaining ecosystem function.

中文翻译：

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河口底栖群落对实验性有机富集的分类和功能响应：生态系统功能的后果

摘要 生态理论指出，生态系统功能对环境干扰的恢复能力取决于支撑它们的生物多样性，但很少有现场验证。在这项研究中，我们探讨了有机质富集后潮间带大型动物群落组成的变化如何影响支撑沙滩生物地球化学和稳定性的官能团 (FG) 的表示和组成。在梯度研究设计中（处理范围为 0 至 2250 g dw m-2），将缓释有机肥加入到试验地块（1.44 m2）中。在与有机物分解（缺氧、酸化和还原溶质浓度增加）相关的沉积物条件发生变化后，70 天后对大型动物群落进行采样。特定分类群对有机富集的敏感性导致 FG 内反应的显着多样性，并且由于干扰在一个 FG 中观察到密度补偿；这使得 FG 即使在高浓度下也能持续存在。尽管如此，在低富集水平和高富集水平之间，群落总丰度下降了 80%，优势类群丰度的大幅下降降低了几个 FG 的生存能力。我们的研究表明大型动物生物多样性与生态系统功能之间存在密度依赖关系，因为底栖初级生产和养分循环的下降与关键分类群丰度的下降显着相关。尽管出现了为 FG 提供弹性的稳定机制，但分类多样性对于维持生态系统功能至关重要。