Natural landscapes are both fragmented and heterogeneous, affecting the distribution of organisms, and their interactions. While predation in homogeneous environments increases the probability of population extinction, fragmentation/heterogeneity promotes coexistence and enhances community stability as shown by experimentation with animals and microorganisms, and supported by theory. Patch connectivity can modulate such effects but how microbial predatory interactions are affected by water-driven connectivity is unknown. In soil, patch habitability by microorganisms, and their connectivity depend upon the water saturation degree (SD). Here, using the obligate bacterial predator Bdellovibrio bacteriovorus, and a Burkholderia prey, we show that soil spatial heterogeneity profoundly affects predatory dynamics, enhancing long-term co-existence of predator and prey in a SD-threshold dependent-manner. However, as patches and connectors cannot be distinguished in these soil matrices, metapopulations cannot be invoked to explain the dynamics of increased persistence. Using a set of experiments combined with statistical and physical models we demonstrate and quantify how under full connectivity, predation is independent of water content but depends on soil microstructure characteristics. In contrast, the SD below which predation is largely impaired corresponds to a threshold below which the water network collapses and water connectivity breaks down, preventing the bacteria to move within the soil matrix.

中文翻译：

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空间异质性在微尺度上稳定了捕食者与猎物之间的相互作用，而斑块连通性则控制着它们的结果。

自然景观既零碎又异质，影响生物的分布及其相互作用。尽管在同质环境中进行捕食会增加种群灭绝的可能性，但片段化/异质性却促进了共存并增强了社区的稳定性，这在动物和微生物实验中得到了证明，并得到了理论的支持。斑块的连通性可以调节这种影响，但是水驱动的连通性如何影响微生物的掠食性相互作用。在土壤中，微生物的斑块可居住性及其连通性取决于水的饱和度（SD）。在这里，我们使用专心的细菌捕食者Bdellovibrio bacteriovorus和Burkholderia猎物，表明土壤空间异质性深刻影响着掠食性动力学，以SD阈值依赖性方式增强捕食者和猎物的长期共存。但是，由于在这些土壤基质中无法区分斑块和连接体，因此无法调用超种群来解释持久性增加的动态。通过使用一组与统计和物理模型相结合的实验，我们演示并量化了在完全连通的情况下，捕食如何与水含量无关，但取决于土壤的微结构特征。相比之下，掠夺力严重受损的SD对应于阈值，低于该阈值水网络崩溃且水连通性崩溃，从而阻止了细菌在土壤基质中移动。不能使用元种群来解释持续性增加的动态。通过使用一组与统计和物理模型相结合的实验，我们演示并量化了在完全连通的情况下，捕食如何与水含量无关，但取决于土壤的微结构特征。相比之下，掠夺力严重受损的SD对应于阈值，低于该阈值水网络崩溃且水连通性崩溃，从而阻止了细菌在土壤基质中移动。不能使用元种群来解释持续性增加的动态。通过使用一组与统计和物理模型相结合的实验，我们演示并量化了在完全连通的情况下，捕食如何与水含量无关，但取决于土壤的微结构特征。相比之下，掠夺力严重受损的SD对应于阈值，低于该阈值水网络崩溃且水连通性崩溃，从而阻止了细菌在土壤基质中移动。