The movement of organisms across habitat boundaries has important consequences for populations, communities, and ecosystems. However, because most species are not well adapted to all habitat types, dispersal into suboptimal habitats could induce physiological changes associated with persistence strategies that influence community assembly. For example, high rates of cross-boundary dispersal are thought to maintain sink populations of terrestrial bacteria in aquatic habitats, but these bacteria may also persist by lowering their metabolic activity, introducing metabolic heterogeneity that buffers the population against species sorting. To differentiate between these assembly processes, we analyzed bacterial composition along a hydrological flow path from terrestrial soils through an aquatic reservoir by sequencing the active and total (active + inactive) portions of the community. When metabolic heterogeneity was ignored, our data were consistent with views that cross-boundary dispersal is important for structuring aquatic bacterial communities. In contrast, we found evidence for strong species sorting in the active portion of the aquatic community, suggesting that dispersal may have a weaker effect than persistence strategies on aquatic community assembly. By accounting for metabolic heterogeneity in complex communities, our findings clarify the roles of local- and regional-scale assembly processes in terrestrial-aquatic meta-ecosystems.

中文翻译：

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跨生态系统边界对细菌群落组装的代谢洞察

生物跨越栖息地边界的移动对种群、社区和生态系统具有重要影响。然而，由于大多数物种并不能很好地适应所有栖息地类型，分散到次优栖息地可能会引起与影响群落组装的持久性策略相关的生理变化。例如，人们认为跨境扩散的高速率可以维持水生栖息地中陆生细菌的汇种群，但这些细菌也可能通过降低其代谢活动、引入代谢异质性来缓冲种群对物种分类的影响而持续存在。为了区分这些组装过程，我们通过对群落的活跃部分和总（活跃 + 不活跃）部分进行排序，分析了沿着从陆地土壤到水库的水文流动路径的细菌组成。当忽略代谢异质性时，我们的数据与跨界扩散对于构建水生细菌群落很重要的观点一致。相比之下，我们发现了在水生群落活跃部分进行强物种分类的证据，这表明散布可能比持久性策略对水生群落组装的影响更弱。通过解释复杂群落中的代谢异质性，我们的研究结果阐明了当地和区域规模的组装过程在陆生元生态系统中的作用。我们的数据与跨界扩散对于构建水生细菌群落很重要的观点一致。相比之下，我们发现了在水生群落活跃部分进行强物种分类的证据，这表明散布可能比持久性策略对水生群落组装的影响更弱。通过解释复杂群落中的代谢异质性，我们的研究结果阐明了当地和区域规模的组装过程在陆生元生态系统中的作用。我们的数据与跨界扩散对于构建水生细菌群落很重要的观点一致。相比之下，我们发现了在水生群落活跃部分进行强物种分类的证据，这表明散布可能比持久性策略对水生群落组装的影响更弱。通过解释复杂群落中的代谢异质性，我们的研究结果阐明了当地和区域规模的组装过程在陆生元生态系统中的作用。