生物如何在群落中共存的問題是生態(tài)學(xué)家的關(guān)鍵問題。要在自然生態(tài)系統(tǒng)中回答這個問題，需要隔離和競爭所有共存成員的艱巨任務(wù)。為了使這個問題在實驗上易于處理，研究人員從穩(wěn)定的合成細(xì)菌群落中分離出生物，并競爭所有可能的生物對組合，以測試它們共同生活的能力。競爭排斥發(fā)生在大多數(shù)配對中，而少數(shù)配對共存。因此，物種共存部分是相互作用網(wǎng)絡(luò)的結(jié)果，是群落集會的新興屬性，表明了維持生物多樣性的重要性。

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過去關(guān)于微生物共存的工作主要集中在物種對上，但尚不清楚在多物種群落中共存是否需要成對共存。為了解決這個問題，研究團(tuán)隊在體外對12個不同富集群落的穩(wěn)定共存成員進(jìn)行了數(shù)百次成對競爭實驗。為了確定這些實驗的結(jié)果，團(tuán)隊成員開發(fā)了一個自動圖像分析管道來量化物種豐度。研究發(fā)現(xiàn)競爭性排斥是最常見的結(jié)果，而且具有很強(qiáng)的等級性和傳遞性。由于在穩(wěn)定的多物種群落中共存的許多物種在相同條件下無法成對共養(yǎng)共存，因此，研究人員得出結(jié)論，多物種共存是一種新興現(xiàn)象。這項工作強(qiáng)調(diào)了社區(qū)背景對于理解復(fù)雜生態(tài)系統(tǒng)中共存起源的重要性。

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原文：

Understanding the mechanisms that maintain microbial biodiversity is a critical aspiration in ecology. Past work on microbial coexistence has largely focused on species pairs, but it is unclear whether pairwise coexistence in isolation is required for coexistence in a multispecies community. To address this question, we conducted hundreds of pairwise competition experiments among the stably coexisting members of 12 different enrichment communities in vitro. To determine the outcomes of these experiments, we developed an automated image analysis pipeline to quantify species abundances. We found that competitive exclusion was the most common outcome, and it was strongly hierarchical and transitive. Because many species that coexist within a stable multispecies community fail to coexist in pairwise co-culture under identical conditions, we concluded that multispecies coexistence is an emergent phenomenon. This work highlights the importance of community context for understanding the origins of coexistence in complex ecosystems.