Finkenstädt B, Keeling M, Grenfell B
Department of Zoology, University of Cambridge, UK.
Proc Biol Sci. 1998 May 7;265(1398):753-62. doi: 10.1098/rspb.1998.0357.
An important question in metapopulation dynamics is the influence of external perturbations on the population's long-term dynamic behaviour. In this paper we address the question of how spatiotemporal variations in demographic parameters affect the dynamics of measles populations in England and Wales. Specifically, we use nonparametric statistical methods to analyse how birth rate and population size modulate the negative density dependence between successive epidemics as well as their periodicity. For the observed spatiotemporal data from 60 cities, and for simulated model data, the demographic variables act as bifurcation parameters on the joint density of the trade-off between successive epidemics. For increasing population size, a transition occurs from an irregular unpredictable pattern in small communities towards a regular, predictable endemic pattern in large places. Variations in the birth rate parameter lead to a bifurcation from annual towards biennial cyclicity in both observed data and model data.
集合种群动态中的一个重要问题是外部扰动对种群长期动态行为的影响。在本文中，我们探讨人口统计学参数的时空变化如何影响英格兰和威尔士麻疹种群的动态。具体而言，我们使用非参数统计方法来分析出生率和种群规模如何调节连续疫情之间的负密度依赖性及其周期性。对于来自60个城市的观测时空数据以及模拟模型数据，人口统计学变量在连续疫情之间权衡的联合密度上充当分岔参数。随着种群规模的增加，会出现从小社区中不规则、不可预测的模式向大地方中规则、可预测的地方病模式的转变。出生率参数的变化在观测数据和模型数据中均导致从年度周期性向两年期周期性的分岔。
