Microbial communities regularly experience ecological invasions that can lead to changes in composition and function. Factors thought to impact susceptibility to invasions, such as diversity and resource use, vary over the course of community assembly. We used synthetic bacterial communities to evaluate the success and impact of invasions occurring at different times during the community assembly process. Fifteen distinct communities were subjected to each of three bacterial invaders at the initial assembly of the community (“initial invasion”), 24 hours into community assembly (“early invasion”), when the community was still undergoing transient dynamics, and 7 days into community assembly (“late invasion”), once the community had settled into its final composition. Communities were passaged daily and characterized through sequencing after reaching a stable composition. Invasions often failed to persist over time, particularly in higher richness communities. However, invasions had their largest effect on composition when they occurred before a community had settled into a stable composition. We found instances where an invader was ultimately excluded yet had profound and long-lasting effects on invaded communities. Invasion outcome was positively associated with lower community richness and resource use efficiency by the community, which varied throughout assembly. Our results demonstrate that microbial communities experiencing transient community dynamics are more affected by, and in some instances prone to, invasion, a finding relevant to efforts to modify the composition of microbial communities.

中文翻译：

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时间对合成细菌群落入侵的影响


微生物群落经常经历生态入侵，这可能导致组成和功能发生变化。被认为影响入侵易感性的因素，例如多样性和资源使用，在群落集会过程中会有所不同。我们使用合成细菌群落来评估群落组装过程中不同时间发生的入侵的成功和影响。15 个不同的群落在群落的初始集会（“初始入侵”）中，群落集结 24 小时后（“早期入侵”），当群落仍在经历瞬态动态时，以及群落集会 7 天后（“晚期入侵”），一旦群落进入其最终组成，就会受到三种细菌入侵者的攻击。群落每天传代，并在达到稳定的组成后通过测序进行表征。入侵往往无法随着时间的推移而持续存在，尤其是在富度较高的群落中。然而，当入侵发生在社区形成稳定的组合之前时，它们对构成的影响最大。我们发现，入侵者最终被排除在外，但对被入侵的社区产生了深远而持久的影响。入侵结果与社区较低的群落丰富度和资源利用效率呈正相关，这在整个集会中有所不同。我们的结果表明，经历瞬态群落动态的微生物群落更容易受到入侵的影响，并且在某些情况下容易受到入侵，这一发现与改变微生物群落组成的努力有关。