The long-term temporal variability and spectral colour of animal populations
The long-term temporal variability and spectral colour of animal populations
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发表时间：
2002
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通讯作者：
P. Inchausti;J. Halley
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作者：
P. Inchausti;J. Halley
我们分析了123个物种的544个自然种群30多年来的时间变异性和光谱颜色。我们使用三种基本测量方法来比较变率随时间增加的趋势（相当于光谱变红）：增加方差指数、30年时间变率和光谱指数。对于每一种，我们都考虑了主要的生态相关因素：分类群、营养水平、纬度、栖息地类型和体型。我们的研究结果证实了先前的发现，即种群变异随着时间的推移而增加，这些生态种群的光谱呈红色。这种效应是普遍存在的，在不同的类群、不同的体型、不同的营养水平、生活在不同的纬度和表现出不同类型的种群动态中都是相似的。一般来说，变红的数量似乎比单纯的环境强迫所预期的要大。此外，没有证据表明生态变异性趋向于有限的极限，尽管变异性的增加确实减缓了。我们的研究结果表明，广泛使用的种群变异度量，如变异系数或丰度对数的标准偏差，应该由光谱变红或种群方差增长率的度量来补充。
We analysed the temporal variability and the spectral colour of 544 natural populations of 123 species that have been censused for more than 30 years. We compared the tendency for variability to increase with time (equivalent to spectral reddening) using three basic measures: an exponent of increasing variance, the 30 year temporal variability and the spectral exponent. For each, we considered the main ecological correlates: taxon, trophic level, latitude, and habitat type and body size. Our results confirm previous findings that population variability increases over time, and those ecological populations have reddened spectra. This effect is universally prevalent, being similar for populations of different taxa, having different body sizes, belonging to different trophic levels, living at different latitudes and exhibiting different types of population dynamics. Generally, the amount of reddening appears to be greater than that expected from environmental forcing alone. Also, there is no evidence that ecological variability tends towards a finite limit, although the increase of variability does decelerate. Our results suggest that widely used measures of population variability, such as the coefficient of variation or standard deviation of the logarithm of abundance, should be supplemented by measures of either spectral reddening or the rate of increase of the population variance.