Sæther Bernt-Erik, Engen Steinar, Pape Møller Anders, Weimerskirch Henri, Visser Marcel E, Fiedler Wolfgang, Matthysen Erik
Am Nat. 2004 Dec;164(6):793-802. doi: 10.1086/425371.
Comparative analyses of avian population fluctuations have shown large interspecific differences in population variability that have been difficult to relate to variation in general ecological characteristics. Here we show that interspecific variation in demographic stochasticity, caused by random variation among individuals in their fitness contributions, can be predicted from a knowledge of the species' position along a "slow-fast" gradient of life-history variation, ranging from high reproductive species with short life expectancy at one end to species that often produce a single offspring but survive well at the other end of the continuum. The demographic stochasticity decreased with adult survival rate, age at maturity, and generation time or the position of the species toward the slow end of the slow-fast life-history gradient. This relationship between life-history characteristics and demographic stochasticity was related to interspecific differences in the variation among females in recruitment as well as to differences in the individual variation in survival. Because reproductive decisions in birds are often subject to strong natural selection, our results provide strong evidence for adaptive modifications of reproductive investment through life-history evolution of the influence of stochastic variation on avian population dynamics.
对鸟类种群波动的比较分析表明，种群变异性存在很大的种间差异，而这些差异很难与一般生态特征的变化联系起来。在这里，我们表明，由个体在其适合度贡献方面的随机变化所导致的种群统计随机性的种间差异，可以根据对物种在“慢-快”生活史变化梯度上位置的了解来预测，这个梯度一端是高繁殖力、预期寿命短的物种，另一端是通常只产一个后代但存活率高的物种。种群统计随机性随着成年存活率、成熟年龄、世代时间或物种在“慢-快”生活史梯度上向慢端的位置而降低。生活史特征与种群统计随机性之间的这种关系，与雌性在补充数量上的变化的种间差异以及存活个体变化的差异有关。由于鸟类的繁殖决策通常受到强烈的自然选择，我们的结果为通过生活史进化对繁殖投资进行适应性调整提供了有力证据，这种调整涉及随机变异对鸟类种群动态的影响。
