Data from: Habitat patch arrangement and metapopulation persistence of predators and prey

This study tests whether spatial dynamics can stabilize metapopulations with a small number of patches and tests the influence of patch arrangement. I measured persistence of predator and prey protists in replicated microcosms with two to four patches. Predators persisted for 85–437 generations (26–130 d). As predicted by single-species and/or predator-prey metapopulation models, substantial variation in predator metapopulation persistence was accounted for by the amount of patches or habitat, number of dispersal corridors, maximum interpatch distance, and proportion of patches providing colonists (which depends on the explicit spatial arrangement of patches). Contrary to expectation, persistence was not influenced by loops of patches or patch similarity. Persistence was also shorter in four-patch loops than three-patch loops, indicating an interaction between patch number and arrangement, which is not predicted by published models. Spatial synchrony of density fluctuations was central to predator persistence but had complex effects on extinction-colonization dynamics, rescue effects, and predator-prey interaction strength. Levins’s model, containing only extinction-colonization dynamics, predicted patch occupancy for prey but not predators. Predators did, however, show rescue effects and changes in interaction strength. This work illustrates the need to combine experimentation with modeling to understand the mechanisms of spatial dynamics.

本研究旨在验证空间动态是否能够稳定具有少量生境斑块的集合种群（metapopulation），并检验斑块布局对其的影响。本研究通过包含2至4个斑块的重复微宇宙实验，测定了捕食者与猎物原生生物的种群存续时长。捕食者的种群存续时长可达85至437代（26至130天）。正如单物种种群或捕食者-猎物集合种群模型所预测的那样，捕食者集合种群存续时长的显著差异，可由斑块/生境数量、扩散廊道数目、最大斑块间距以及提供拓殖个体的斑块占比（该占比取决于斑块的具体空间布局）予以解释。但与预期相悖的是，种群存续时长并未受到斑块环或斑块相似性的影响。此外，4斑块环中的种群存续时长短于3斑块环，这表明斑块数量与布局之间存在交互作用，而现有已发表的模型并未预测到该交互作用。密度波动的空间同步性是捕食者种群存续的核心影响因素，但对灭绝-拓殖动态、救援效应以及捕食者-猎物相互作用强度具有复杂的调控作用。仅包含灭绝-拓殖动态的莱文斯模型（Levins’s model）能够预测猎物的斑块占有率，但无法预测捕食者的斑块占有率。但捕食者确实表现出救援效应以及相互作用强度的变化。本研究表明，若要阐明空间动态的作用机制，需将实验研究与模型构建相结合。