From stochastic environments to life histories and back
From stochastic environments to life histories and back
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从随机环境到生活史并返回
DOI：
10.1098/rstb.2009.0021
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
T. Coulson
中科院分区：
文献类型：
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作者：
S. Tuljapurkar;J. Gaillard;T. Coulson
众所周知，环境随机性在生命史进化中起着重要作用，但大多数一般理论假设环境是恒定的。在本文中，我们通过将平均个体适应度（由长期随机生长率衡量）分解为平均生命率及其时间变化的贡献，研究了可变环境中的生活史进化。我们研究了世代时间、人口分散（通过整个生命周期中生殖事件的分散来衡量）、人口弹性（通过阻尼时间来衡量）、生命率的年内方差、生命率之间的年内相关性和生命率的年之间相关性如何结合起来决定风格化生活史的平均个体适合度。在波动的环境中，我们发现通常存在一个适应度达到最大值的世代世代时间范围。因此，我们期望波动环境中的“最佳”表型与恒定环境中的最佳表型不同。我们表明，即使确定性增长率不受人口分散的影响，随机增长率也会受到人口分散的强烈影响，而且人口分散也决定了生活史特定平均适应度对年内和年内相关性的响应。序列相关性对适应度有很强的影响，并且根据生活史的结构，可能会增加或降低适应度。我们概述的方法为发展非恒定环境的一般生活史理论迈出了有用的第一步。
Environmental stochasticity is known to play an important role in life-history evolution, but most general theory assumes a constant environment. In this paper, we examine life-history evolution in a variable environment, by decomposing average individual fitness (measured by the long-run stochastic growth rate) into contributions from average vital rates and their temporal variation. We examine how generation time, demographic dispersion (measured by the dispersion of reproductive events across the lifespan), demographic resilience (measured by damping time), within-year variances in vital rates, within-year correlations between vital rates and between-year correlations in vital rates combine to determine average individual fitness of stylized life histories. In a fluctuating environment, we show that there is often a range of cohort generation times at which the fitness is at a maximum. Thus, we expect ‘optimal’ phenotypes in fluctuating environments to differ from optimal phenotypes in constant environments. We show that stochastic growth rates are strongly affected by demographic dispersion, even when deterministic growth rates are not, and that demographic dispersion also determines the response of life-history-specific average fitness to within- and between-year correlations. Serial correlations can have a strong effect on fitness, and, depending on the structure of the life history, may act to increase or decrease fitness. The approach we outline takes a useful first step in developing general life-history theory for non-constant environments.