Kaitala V, Ylikarjula J, Ranta E, Lundberg P
Symptoms Analysis Laboratory, Helsinki University of Technology, Finland.
Proc Biol Sci. 1997 Jul 22;264(1384):943-8. doi: 10.1098/rspb.1997.0130.
The effect of red, white and blue environmental noise on discrete-time population dynamics is analyzed. The coloured noise is superimposed on Moran-Ricker and Maynard Smith dynamics, the resulting power spectra are less than examined. Time series dominated by short- and long-term fluctuations are said to be blue and red, respectively. In the stable range of the Moran-Ricker dynamics, environmental noise of any colour will make population dynamics red or blue depending the intrinsic growth rate. Thus, telling apart the colour of the noise from the colour of the population dynamics may not be possible. Population dynamics subjected to red and blue environmental noises show, respectively, more red or blue power spectra than those subjected to white noise. The sensitivity to differences in the noise colours decreases with increasing complexity and ultimately disappears in the chaotic range of the population dynamics. These findings are duplicated with the Maynard Smith model for high growth rates when the strength of density dependence changes. However, for low growth rates the power spectra of the population dynamics with noise are red in stable, periodic and aperiodic ranges irrespective of the noise colour. Since chaotic population fluctuations may show blue spectra in the deterministic case, this implies that blue deterministic chaos may become red under any colour of the noise.
分析了红、白、蓝环境噪声对离散时间种群动态的影响。有色噪声叠加在莫兰-里克动力学和梅纳德·史密斯动力学上，所得功率谱小于所研究的情况。分别由短期和长期波动主导的时间序列被称为蓝色和红色。在莫兰-里克动力学的稳定范围内，任何颜色的环境噪声都会使种群动态变为红色或蓝色，这取决于内在增长率。因此，可能无法区分噪声的颜色和种群动态的颜色。受到红色和蓝色环境噪声影响的种群动态分别比受到白色噪声影响的种群动态显示出更多的红色或蓝色功率谱。随着种群动态复杂性的增加，对噪声颜色差异的敏感性降低，最终在种群动态的混沌范围内消失。当密度依赖强度变化时，对于高增长率，梅纳德·史密斯模型也会出现这些结果。然而，对于低增长率，无论噪声颜色如何，有噪声的种群动态功率谱在稳定、周期和非周期范围内都是红色的。由于在确定性情况下混沌种群波动可能显示蓝色谱，这意味着在任何颜色的噪声下，蓝色确定性混沌可能会变为红色。
