The mechanisms of species coexistence make ecologists fascinated, although theoretical work shows that omnivory can promote coexistence of species and food web stability, it is still a lack of the general mechanisms for species coexistence in the real food webs, and is unknown how omnivory affects the interactions between competitor and predator. In this work, we first establish an omnivorous food web model with a competitor based on two natural ecosystems (the plankton community and fig–fig wasp system). We analyze the changes of both food web structure and stability under the different resource levels and predation preference of the generalist/top predator. The results of model analyses show that weak predation strength can promote stable coexistence of predators and prey. Moreover, the evolutionary trend of food web structure changes with the relative predation strength is more diverse than the relative competition strength, and an integration of both omnivory, increased competition, top-down control and bottom-up control can promote species diversity and food web stability. Our theoretical predictions are consistent with empirical data in the plankton community: the lower concentration of nutrient results in a more stable population dynamics. Our theoretical work could enrich the general omnivorous theory on species coexistence and system stability in the real food webs.

中文翻译：

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弱捕食强度促进捕食者和猎物同链和跨链稳定共存

物种共存机制令生态学家着迷，虽然理论工作表明杂食性能够促进物种共存和食物网稳定，但在真实食物网中尚缺乏物种共存的一般机制，且不知道杂食性如何影响物种共存。竞争者和捕食者之间的相互作用。在这项工作中，我们首先与竞争对手建立了一个基于两个自然生态系统（浮游生物群落和无花果蜂系统）的杂食性食物网模型。我们分析了在不同资源水平和通才/顶级捕食者的捕食偏好下食物网结构和稳定性的变化。模型分析结果表明，弱捕食强度可以促进捕食者和猎物稳定共存。而且，食物网结构随相对捕食强度变化的演化趋势比相对竞争强度更多样化，杂食性、竞争加剧、自上而下控制和自下而上控制相结合可以促进物种多样性和食物网稳定性。我们的理论预测与浮游生物群落的经验数据一致：养分浓度越低，种群动态就越稳定。我们的理论工作可以丰富关于真实食物网中物种共存和系统稳定性的一般杂食性理论。我们的理论预测与浮游生物群落的经验数据一致：养分浓度越低，种群动态就越稳定。我们的理论工作可以丰富关于真实食物网中物种共存和系统稳定性的一般杂食性理论。我们的理论预测与浮游生物群落的经验数据一致：养分浓度越低，种群动态就越稳定。我们的理论工作可以丰富关于真实食物网中物种共存和系统稳定性的一般杂食性理论。