Effective size of fluctuating populations with two sexes and overlapping generations
Effective size of fluctuating populations with two sexes and overlapping generations
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DOI：
10.1111/j.1558-5646.2007.00155.x
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发表时间：
2007-08-01
期刊：
影响因子：
3.3
通讯作者：
Ellegren, Hans
中科院分区：
文献类型：
--
作者：
Engen, Steinar;Ringsby, Thor Harald;Ellegren, Hans
我们推导出的公式，可以应用于估计有效的人口规模N-E的生物体与两种性别每年繁殖一次，并有恒定的成人平均生命率独立于年龄。人口规模的时间波动是由人口和环境的随机性造成的。对于出生性别比均匀、人口增长不确定且两性平均生命率相同的人口，确定N-e的关键参数只是分别考虑男性和女性的人口统计方差的平均值。在这种情况下，Crow和Kimura将Wright的N-e公式推广到两种性别，根据每种性别的有效人口规模，甚至适用于男性和女性生命率具有不同随机性的波动人口。如果平均生命率是不同的性别，然后一个简单的线性组合的人口方差确定N-E，进一步扩展赖特的公式。对于长寿的物种的表达式是来自N-电子涉及两性的世代时间。在人口增长率为非零且新生儿性别比不均匀的一般情况下，我们利用该模型数值研究了不同人口参数对N-e的影响。我们还估计了挪威北方海岸外岛屿上6个家雀种群的有效种群规模与实际种群规模的比率。这一比例显示，由于人口之间的人口差异，性别差异很大。最后，我们计算如何N-e在不断增长的家雀种群将随着时间的推移而变化。
We derive formulas that can be applied to estimate the effective population size N-e for organisms with two sexes reproducing once a year and having constant adult mean vital rates independent of age. Temporal fluctuations in population size are generated by demographic and environmental stochasticity. For populations with even sex ratio at birth, no deterministic population growth and identical mean vital rates for both sexes, the key parameter determining N-e is simply the mean value of the demographic variance for males and females considered separately. In this case Crow and Kimura's generalization of Wright's formula for N-e with two sexes, in terms of the effective population sizes for each sex, is applicable even for fluctuating populations with different stochasticity in vital rates for males and females. If the mean vital rates are different for the sexes then a simple linear combination of the demographic variances determines N-e, further extending Wright's formula. For long-lived species an expression is derived for N-e involving the generation times for both sexes. In the general case with nonzero population growth and uneven sex ratio of newborns, we use the model to investigate numerically the effects of different population parameters on N-e. We also estimate the ratio of effective to actual population size in six populations of house sparrows on islands off the coast of northern Norway. This ratio showed large interisland variation because of demographic differences among the populations. Finally, we calculate how N-e in a growing house sparrow population will change over time.