小柯机器人

德国奥尔登堡大学Bernd Blasius等研究人员合作揭示了实验性捕食与猎物系统中的长期循环持久性。这一研究成果2019年12月18日在线发表在国际学术期刊《自然》上。

研究人员使用浮游式捕食者与猎物系统进行了缩影实验，并反复观察到了前所未有长度的振荡时间序列，其持续了大约50个周期或大约300个捕食者世代。动态的主要类型特征是规则的、相干的振荡，其捕食者与猎物的相位差几乎恒定。尽管实验条件恒定，研究人员还观察到较短的不规则的、非相干振荡事件，且没有明显的相位关系。但是，捕食者与猎物系统显示出强烈的趋势，即回到具有确定相位关系的主导动态体系。数学模型表明，随机性可能是导致相干振荡向非相干振荡可逆转变的原因，这一观点得到了突然养分供应外部强迫实验的支持。这些发现从经验上证明了在周期性动态机制中捕食者和猎物种群之间无限持久性的潜力，这种动态机制在随机事件发生的情况下显示了适应能力。

据介绍，捕食者与猎物的循环是生态学中最基本的概念之一，可以通过最简单的生态模型进行预测，并且在理论上可以实现捕食者和猎物的无限持久性。 但是，在现实群体中，循环动态能够自我维持多长时间仍然是一个悬而未决的问题。野外观察仅限于几个周期，此外实验研究表明，在没有外部稳定因素情况下，振荡可能是短暂的。

附：英文原文

Title: Long-term cyclic persistence in an experimental predator–prey system

Author: Bernd Blasius, Lars Rudolf, Guntram Weithoff, Ursula Gaedke, Gregor F. Fussmann

Issue&Volume: 2019-12-18

Abstract: Predatorprey 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 prey14. 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 periods58 and experimental studies indicate that oscillations may be short-lived without external stabilizing factors919. Here we performed microcosm experiments with a planktonic predatorprey 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 predatorprey phase difference. Despite constant experimental conditions, we also observed shorter episodes of irregular, non-coherent oscillations without any significant phase relationship. However, the predatorprey 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. The potential for infinite persistence of planktonic predator and prey cycles is experimentally demonstrated and these cycles show resilience in the presence of stochastic events.

DOI: 10.1038/s41586-019-1857-0

Source:https://www.nature.com/articles/s41586-019-1857-0

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