Nearest-neighbor interactions, habitat fragmentation, and the persistence of host-pathogen systems.
Nearest-neighbor interactions, habitat fragmentation, and the persistence of host-pathogen systems.
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DOI：
10.1086/671185
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发表时间：
2013-09
期刊：
影响因子：
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通讯作者：
Komarova NL
中科院分区：
文献类型：
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作者：
Wodarz D;Sun Z;Lau JW;Komarova NL
众所周知，如果在混合良好的环境中发生不稳定和灭绝，空间相互作用可以促进敌害相互作用的稳定性和持久性。我们研究了相反情况下空间相互作用的影响，在这种情况下，种群可以持续存在于混合良好的系统中。基于随机主体的宿主-病原体动力学模型被认为描述了未分割栖息地中的最近邻相互作用。与之前的观念相反，我们发现在这种情况下，空间相互作用实际上促进了灭绝。原因是，与大规模行动系统相比，最近邻模型的结果是由小型“局部社区”的动态控制的。这是一个抽象，描述了由个体及其最近邻居组成的最小网格中的交互。该特征尺度较小，导致灭绝概率较高。因此，连续栖息地中的最近邻相互作用会导致让人想起破碎栖息地的结果，明确假设栖息地破碎的集合种群模型进一步强调了这一点。除了宿主-病原体动力学之外，公理化模型表明我们的结果适用于特定假设下的一般敌人-受害者相互作用。这些结果用于解释一组已发表的实验，这些实验为模型测试提供了第一步，并在文献中进行了讨论。
Spatial interactions are known to promote stability and persistence in enemy-victim interactions if instability and extinction occur in well-mixed settings. We investigate the effect of spatial interactions in the opposite case, where populations can persist in well-mixed systems. A stochastic agent-based model of host-pathogen dynamics is considered that describes nearest-neighbor interactions in an undivided habitat. Contrary to previous notions, we find that in this setting, spatial interactions in fact promote extinction. The reason is that, in contrast to the mass-action system, the outcome of the nearest-neighbor model is governed by dynamics in small “local neighborhoods.” This is an abstraction that describes interactions in a minimal grid consisting of an individual plus its nearest neighbors. The small size of this characteristic scale accounts for the higher extinction probabilities. Hence, nearest-neighbor interactions in a continuous habitat lead to outcomes reminiscent of a fragmented habitat, which is underlined further with a metapopulation model that explicitly assumes habitat fragmentation. Beyond host-pathogen dynamics, axiomatic modeling shows that our results hold for generic enemy-victim interactions under specified assumptions. These results are used to interpret a set of published experiments that provide a first step toward model testing and are discussed in the context of the literature.