Meng Yu, Jiang Junjie, Grebogi Celso, Lai Ying-Cheng
Institute for Complex Systems and Mathematical Biology, School of Natural and Computing Sciences, King's College, University of Aberdeen, Aberdeen AB24 3UE, United Kingdom.
School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287, USA.
Phys Rev E. 2020 Jan;101(1-1):012206. doi: 10.1103/PhysRevE.101.012206.
The beneficial role of noise in promoting species coexistence and preventing extinction has been recognized in theoretical ecology, but previous studies were mostly concerned with low-dimensional systems. We investigate the interplay between noise and nonlinear dynamics in real-world complex mutualistic networks with a focus on species recovery in the aftermath of a tipping point. Particularly, as a critical parameter such as the mutualistic interaction strength passes through a tipping point, the system collapses and approaches an extinction state through a dramatic reduction in the species populations to near-zero values. We demonstrate the striking effect of noise: when the direction of parameter change is reversed through the tipping point, noise enables species recovery which otherwise would not be possible. We uncover an algebraic scaling law between the noise amplitude and the parameter distance from the tipping point to the recovery point and provide a physical understanding through analyzing the nonlinear dynamics based on an effective, reduced-dimension model. Noise, in the form of small population fluctuations, can thus play a positive role in protecting high-dimensional, complex ecological networks.
噪声在促进物种共存和防止灭绝方面的有益作用在理论生态学中已得到认可，但先前的研究大多关注低维系统。我们研究现实世界复杂互利网络中噪声与非线性动力学之间的相互作用，重点关注临界点之后的物种恢复情况。特别是，当诸如互利相互作用强度等关键参数通过临界点时，系统会崩溃，并通过物种数量急剧减少至接近零值而趋近灭绝状态。我们证明了噪声的显著作用：当参数变化方向通过临界点反转时，噪声能使物种得以恢复，否则这是不可能的。我们揭示了噪声幅度与从临界点到恢复点的参数距离之间的代数标度律，并通过基于有效低维模型分析非线性动力学给出了物理理解。因此，以小种群波动形式存在的噪声在保护高维复杂生态网络方面可发挥积极作用。
