Abstract

Defaunation including invertebrate decline is one of the major consequences of anthropogenic alterations of the environment. Despite recent reports of ubiquitous invertebrate decline, the ecosystem consequences have been rarely documented. We exposed standardized plant communities grown in the iDiv Ecotron to different levels of invertebrate numbers and biomass and tracked effects on the diversity and composition of bacterial communities associated with flowers and leaves of Scorzoneroides autumnalis and Trifolium pratense using next-generation 16S rRNA gene amplicon sequencing. Our data indicate that invertebrate decline reduces bacterial richness and β-diversity and alters community composition. These effects may result from direct effects of invertebrates that may serve as dispersal agents of bacteria; or from indirect effects where animal-induced changes in the plant's phenotype shape the niches plants provide for bacterial colonizers. Because bacteria are usually not dispersal limited and because species sorting, i.e. niche-based processes, has been shown to be a dominant process in bacterial community assembly, indirect effects may be more likely. Given that a healthy microbiome is of fundamental importance for the well-being of plants, animals (including humans) and ecosystems, a loss of bacterial diversity may be a dramatic yet previously unknown consequence of current invertebrate decline.

中文翻译：

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无脊椎动物的衰退减少了与叶子和花朵相关的细菌多样性

摘要

包括无脊椎动物衰退在内的动物区系丧失是人为环境改变的主要后果之一。尽管最近有无脊椎动物衰退的报道，但生态系统的后果却鲜有记载。我们将 iDiv Ecotron 中生长的标准化植物群落暴露于不同水平的无脊椎动物数量和生物量，并使用下一代 16S rRNA 基因扩增子测序跟踪与ScorzoneroidesAutumnalis和Trifolium pratense 的花和叶相关的细菌群落多样性和组成的影响。我们的数据表明，无脊椎动物的减少会降低细菌丰富度和β-多样性并改变社区组成。这些影响可能是由无脊椎动物的直接影响引起的，这些无脊椎动物可能是细菌的传播媒介；或者来自动物引起的植物表型变化的间接影响，从而塑造了植物为细菌定植者提供的生态位。因为细菌通常不受扩散限制，并且因为物种分类，即基于生态位的过程，已被证明是细菌群落组装的主要过程，间接影响可能更有可能。鉴于健康的微生物组对植物、动物（包括人类）和生态系统的福祉至关重要，细菌多样性的丧失可能是当前无脊椎动物减少的一个戏剧性但以前未知的后果。