Indian Institute of Science Education and Research Mohali, Knowledge City, Sector 81, Manauli, 140306, India.
Indian Institute of Technology, Bombay, Powai, Mumbai, 400076, India.
Sci Rep. 2020 Jun 30;10(1):10613. doi: 10.1038/s41598-020-67517-1.
We study the dynamics of a ring of patches with vegetation-prey-predator populations, coupled through interactions of the Lotka-Volterra type. We find that the system yields aperiodic, recurrent and rare explosive bursts of predator density in a few isolated spatial patches from time to time. Further, the global predator biomass also exhibits sudden uncorrelated occurrences of large deviations from the mean as the coupled system evolves. The maximum value of the predator population in a patch, as well as the maximum value of the predator biomass, increases with coupling strength. These trends are further corroborated by fits to Generalized Extreme Value distributions, where the location and scale factor of the distribution increases markedly with coupling strength, indicating the crucial role of coupling interactions in the generation of extreme events. These results indicate how occurrences of extremely large predator populations can emerge in coupled population dynamics, and in a more general context they suggest a generic class of deterministic nonlinear systems that can naturally exhibit extreme events.
我们研究了具有植被-猎物-捕食者种群的环斑的动力学，这些种群通过Lotka-Volterra 型相互作用耦合在一起。我们发现，该系统会在少数孤立的空间斑块中不时产生非周期性、周期性和罕见的捕食者密度爆发。此外，随着耦合系统的演化，全球捕食者生物量也会突然出现与平均值的无关联的大偏差。斑块中捕食者种群的最大值以及捕食者生物量的最大值都会随着耦合强度的增加而增加。广义极值分布的拟合进一步证实了这些趋势，其中分布的位置和尺度因子随着耦合强度的显著增加，表明耦合相互作用在极端事件的产生中起着关键作用。这些结果表明，在耦合种群动力学中，极端大的捕食者种群的出现是如何发生的，而更普遍的情况是，它们表明了一类可以自然表现出极端事件的通用确定性非线性系统。
