Moitra Promit, Sinha Sudeshna
Indian Institute of Science Education and Research Mohali, Knowledge City, Sector 81, SAS Nagar, Manauli PO 140 306, Punjab, India.
Chaos. 2019 Feb;29(2):023131. doi: 10.1063/1.5063926.
We consider a collection of populations modelled by the prototypical chaotic Ricker map, relevant to the population growth of species with non-overlapping generations. The growth parameter of each population patch is influenced by the local mean field of its neighbourhood, and we explore the emergent patterns in such a parametrically coupled network. In particular, we examine the dynamics and distribution of the local populations, as well as the total biomass. Our significant finding is the following: When the range of coupling is sufficiently large, namely, when enough neighbouring populations influence the growth rate of a population, the system yields remarkably large biomass values that are very far from the mean. These extreme events are relatively rare and uncorrelated in time. We also find that at any point in time, exceedingly large population densities emerge in a few patches, analogous to an extreme event in space. Thus, we suggest a new mechanism in coupled chaotic systems that naturally yield extreme events in both time and space.
我们考虑一组由典型的混沌里克特映射建模的种群，这与具有不重叠世代的物种的种群增长相关。每个种群斑块的增长参数受其邻域的局部平均场影响，并且我们探索这种参数耦合网络中出现的模式。特别地，我们研究局部种群的动态和分布以及总生物量。我们的重要发现如下：当耦合范围足够大时，即当足够多的相邻种群影响一个种群的增长率时，系统会产生显著大的生物量值，这些值与平均值相差甚远。这些极端事件相对罕见且在时间上不相关。我们还发现，在任何时刻，少数斑块中会出现极大的种群密度，类似于空间中的极端事件。因此，我们提出了一种耦合混沌系统中的新机制，该机制自然会在时间和空间上产生极端事件。
