Long-term cyclic persistence in an experimental predator-prey system
Long-term cyclic persistence in an experimental predator-prey system
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DOI：
10.1038/s41586-019-1857-0
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发表时间：
2020-01-09
期刊：
影响因子：
64.8
通讯作者：
Fussmann, Gregor F.
中科院分区：
文献类型：
--
作者：
Blasius, Bernd;Rudolf, Lars;Fussmann, Gregor F.
捕食者-被捕食者循环是生态学中最基本的概念之一，由最简单的生态模型预测，理论上，捕食者和被捕食者的无限期持续存在（1-4）。然而，在真实的社区中，循环动力学能够自我维持多久仍然是一个悬而未决的问题。现场观测仅限于几个周期（5-8），实验研究表明，如果没有外部稳定因素，振荡可能是短暂的（9-19）。在这里，我们进行了微观实验，一个非稳态的捕食者-被捕食者系统，并反复观察振荡的时间序列的前所未有的长度，持续约50个周期或约300捕食者代。主要类型的动态的特点是经常，连贯的振荡与一个几乎恒定的捕食者-猎物相位差。尽管恒定的实验条件下，我们也观察到较短的不规则，非相干振荡没有任何显着的相位关系。然而，捕食者-食饵系统表现出强烈的趋势，返回到一个定义的相位关系的主导动力学制度。一个数学模型表明，随机性可能是负责从相干到非相干振荡的可逆转变，这一概念得到了实验的支持与脉冲营养供应的外部强迫。我们的研究结果实证证明了潜在的无限持久性的捕食者和猎物种群在一个循环的动态制度，表现出弹性的随机事件的存在。
Predator-prey cycles rank among the most fundamental concepts in ecology, are predicted by the simplest ecological models and enable, theoretically, the indefinite persistence of predator and prey(1-4). However, it remains an open question for how long cyclic dynamics can be self-sustained in real communities. Field observations have been restricted to a few cycle periods(5-8) and experimental studies indicate that oscillations may be short-lived without external stabilizing factors(9-19). Here we performed microcosm experiments with a planktonic predator-prey system and repeatedly observed oscillatory time series of unprecedented length that persisted for up to around 50 cycles or approximately 300 predator generations. The dominant type of dynamics was characterized by regular, coherent oscillations with a nearly constant predator-prey phase difference. Despite constant experimental conditions, we also observed shorter episodes of irregular, non-coherent oscillations without any significant phase relationship. However, the predator-prey system showed a strong tendency to return to the dominant dynamical regime with a defined phase relationship. A mathematical model suggests that stochasticity is probably responsible for the reversible shift from coherent to non-coherent oscillations, a notion that was supported by experiments with external forcing by pulsed nutrient supply. Our findings empirically demonstrate the potential for infinite persistence of predator and prey populations in a cyclic dynamic regime that shows resilience in the presence of stochastic events.