Stabilization of extensive fine -scale diversity by driven chaos
Stabilization of extensive fine -scale diversity by driven chaos
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DOI：
10.1073/pnas.1915313117
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发表时间：
2020-06-23
影响因子：
11.1
通讯作者：
Fisher, Daniel S.
中科院分区：
文献类型：
--
作者：
Pearce, Michael T.;Agarwala, Atish;Fisher, Daniel S.
最近已经变得很明显，微生物生命的多样性远远低于物种水平，延伸到最细微的遗传差异尺度。值得注意的是，广泛的精细尺度多样性可以在空间上共存。尽管存在选择性或生态差异以及其他进化过程，但这种多样性如何在长时间尺度上保持稳定？大多数工作都集中在稳定共存或假设生态中立。我们提出了另一种选择：由生态驱动的时空混沌维持广泛的多样性，不假设菌株之间的生态位或其他专业差异。我们研究了广义 Lotka Volterra 模型，该模型在感染多种宿主菌株的多种病原体菌株的启发下，在相互作用中具有反对称相关性。一般来说，这些地区表现出混乱，人口波动日益剧烈，导致物种灭绝。但最简单的空间结构，许多相同的岛屿以及它们之间的迁移，稳定了多样化的混乱状态。一些菌株（亚种）在全球范围内灭绝，但许多菌株在岛屿数量上持续存在的时间呈指数级增长。所有持久性菌株都会在局部出现高度丰度的间歇性开花，这对于它们的持久性至关重要，因为对于许多菌株来说，它们的平均种群增长率为负。丰度分布的快照显示了中等丰度的幂律，这与生态学的中性理论本质上没有区别。但大量人口的动态比出生死亡的波动要快得多。我们认为，这种时空混沌“相”应该存在于广泛的模型中，并且即使在快速混合的系统中，寿命较长的孢子也可以类似地稳定多样化的混沌相。
It has recently become apparent that the diversity of microbial life extends far below the species level to the finest scales of genetic differences. Remarkably, extensive fine -scale diversity can coexist spatially. How is this diversity stable on long timescales, despite selective or ecological differences and other evolutionary processes? Most work has focused on stable coexistence or assumed ecological neutrality. We present an alternative: extensive diversity maintained by ecologically driven spatiotemporal chaos, with no assumptions about niches or other specialist differences between strains. We study generalized Lotka Volterra models with antisymmetric correlations in the interactions inspired by multiple pathogen strains infecting multiple host strains. Generally, these exhibit chaos with increasingly wild population fluctuations driving extinctions. But the simplest spatial structure, many identical islands with migration between them, stabilizes a diverse chaotic state. Some strains (subspecies) go globally extinct, but many persist for times exponentially long in the number of islands. All persistent strains have episodic local blooms to high abundance, crucial for their persistence as, for many, their average population growth rate is negative. Snapshots of the abundance distribution show a power law at intermediate abundances that is essentially indistinguishable from the neutral theory of ecology. But the dynamics of the large populations are much faster than birth death fluctuations. We argue that this spatiotemporally chaotic "phase" should exist in a wide range of models, and that even in rapidly mixed systems, longer-lived spores could similarly stabilize a diverse chaotic phase.