Chaos and stability in the marine trophic network: the importance of interactions over complexity
海洋营养网络中的混沌与稳定性:相互作用比复杂性更重要
Ilaria Cunico, Guido Occhipinti, Gregor Fussmann, Paolo Lazzari
AI总结 通过数值模拟研究复杂海洋营养网络动力学,发现较长的营养链和更多的消费者增加混沌性,而杂食性相互作用促进稳定性,表明相互作用而非复杂性是稳定性的关键驱动因素。
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理解现实世界复杂网络的动力学对于评估其可预测性、恢复力以及改善生态系统管理至关重要,尤其是在气候变化的背景下。生态网络中稳定性与复杂性之间的关系在文献中仍存在争议。在这项建模研究中,我们探讨了一个以多种营养相互作用和环境约束为特征的复杂海洋营养网络是否表现出主要稳定、周期或混沌动力学。我们将微生物环纳入营养网络模型,该模型包括一到三个初级生产者、一个或两个消费者,以及多达三个营养级的捕食者。微生物环是一个关键过程,其中细菌将来自较高营养级的碎屑回收为可供初级生产者生长的营养物质,确保系统内的质量守恒。我们进行数值模拟以研究网络的动态行为,通过关闭物种间的捕食-被捕食链接并探索高维参数空间,考察了几种配置。我们的结果表明:(i) 较长的营养链和 (ii) 更多的消费者增加了系统的混沌性,而 (iii) 杂食性相互作用促进了稳定性。值得注意的是,许多配置表现出高比例的混沌行为。反馈环分析表明,负反馈和正反馈之间的平衡在系统趋向稳态的过程中起着关键作用。这项研究表明,相互作用和反馈,而非复杂性,是稳定性的关键驱动因素,指出了稳定性-复杂性关系的不明确性,反而强调了稳定性-相互作用的依赖性。混沌动力学也可能发挥重要作用,对可预测性和生态系统管理具有潜在影响。
Understanding the dynamics of real world complex networks is crucial for assessing their predictability, resilience, and improving ecosystem management, especially in the context of climate change. The relationship between stability and complexity in ecological networks is still debated in the literature. In this modeling study, we investigate whether a complex marine trophic network, characterized by multiple trophic interactions and environmental constraints, exhibits predominantly stable, periodic or chaotic dynamics. We incorporate the microbial loop into a trophic network model, which includes one to three primary producers, one or two consumers, and up to three trophic levels of predators. The microbial loop is a key process in which bacteria recycle detritus from higher trophic levels into nutrients available for the growth of primary producers, ensuring mass conservation within the system. We perform numerical simulations to investigate the dynamic behavior of the network, exploring several configurations by turning off predator prey links between species and varying the high dimensional parameter space. Our results show that (i) longer trophic chains and (ii) a higher number of consumers increase system chaoticity, whereas (iii) omnivorous interactions promote stability. Notably, many of the configurations exhibit high percentages of chaotic behavior. Feedback loop analysis suggests that the balance between negative and positive interactions plays a key role in the convergence of the system toward a steady state. This study shows that interactions and feedback, rather than complexity, are key drivers of stability, pointing to the absence of a clear stability complexity relationship and instead highlighting a stability interaction dependence. Chaotic dynamics may also play an important role, with potential implications for predictability and ecosystem management.