University of Georgia, Odum School of Ecology, Athens, Georgia 30602, USA.
Ecology. 2012 Apr;93(4):793-802. doi: 10.1890/11-0742.1.
The theory of evolution via natural selection predicts that the genetic composition of wild populations changes over time in response to the environment. Different genotypes should exhibit different demographic patterns, but genetic variation in demography is often impossible to separate from environmental variation. Here, we asked if genetic variation is important in determining demographic patterns. We answer this question using a long-term field experiment combined with general linear modeling of deterministic population growth rates (lambda), deterministic life table response experiment (LTRE) analysis, and stochastic simulation of demography by paternal lineage in a short-lived perennial plant, Plantago lanceolata, in which we replicated genotypes across four cohorts using a standard breeding design. General linear modeling showed that growth rate varied significantly with year, spatial block, and sire. In LTRE analysis of all cohorts, the strongest influences on growth rate were from year x spatial block, and cohort x year x spatial block interactions. In analysis of genetics vs. temporal environmental variation, the strongest impacts on growth rate were from year and year x sire. Finally, stochastic simulation suggested different genetic composition among cohorts after 100 years, and different population growth rates when genetic differences were accounted for than when they were not. We argue that genetic variation, genotype x environment interactions, natural selection, and cohort effects should be better integrated into population ecological studies, as these processes should result in deviations from projected deterministic and stochastic population parameters.
自然选择进化理论预测，野生种群的基因组成会随着时间的推移而发生变化，以适应环境。不同的基因型应该表现出不同的人口统计学模式，但人口统计学中的遗传变异通常与环境变化无法区分。在这里，我们想知道遗传变异是否对确定人口统计学模式很重要。我们通过长期的野外实验，结合确定性种群增长率（lambda）的一般线性建模、确定性生命表响应实验（LTRE）分析以及通过父系在一个短寿命多年生植物 Plantago lanceolata 中进行的人口统计学随机模拟来回答这个问题，我们在四个群体中使用标准的繁殖设计复制了基因型。一般线性建模表明，增长率随年份、空间块和 sire 显著变化。在所有队列的 LTRE 分析中，对增长率影响最大的是年份 x 空间块和队列 x 年份 x 空间块的相互作用。在遗传与时间环境变化的分析中，对增长率影响最大的是年份和年份 x sire。最后，随机模拟表明，100 年后，不同队列之间的遗传组成不同，当考虑遗传差异时，种群增长率与不考虑遗传差异时不同。我们认为，遗传变异、基因型 x 环境相互作用、自然选择和群体效应应该更好地纳入种群生态学研究中，因为这些过程应该导致与预测的确定性和随机种群参数的偏差。
