Evaluating the importance of individual heterogeneity in reproduction to Weddell seal population dynamics using integral projection models
Evaluating the importance of individual heterogeneity in reproduction to Weddell seal population dynamics using integral projection models
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DOI：
10.1111/1365-2656.13975
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发表时间：
2023-07-03
影响因子：
4.8
通讯作者：
Paterson，J. Terrill
中科院分区：
文献类型：
--
作者：
Macdonald，Kaitlin R. R.;Rotella，Jay J. J.;Paterson，J. Terrill
在人口统计学模型中识别和解释生命率中未观察到的个体异质性对于估计人群水平的生命率和识别不同的生活史策略非常重要，但关于个体异质性如何影响种群动态的研究却知之甚少，我们的目的是利用威德尔海豹种群的生命率来了解个体异质性在繁殖率和存活率上的分布如何影响种群动态通过改变繁殖中个体异质性的分布，这也改变了个体存活率的分布，通过纳入我们对两个比率之间相关性的估计，并评估由此导致的人口增长变化。根据年龄和生殖状态进行结构化，使用最近显示出较大个体异质性的长寿哺乳动物的生命率估计值在繁殖方面。利用IPM的输出，我们评估了种群动态如何随着未观察到的个体繁殖异质性的不同潜在分布而变化，结果表明，个体繁殖异质性的潜在分布的变化导致种群增长率和其他种群指标的变化很小。个体异质性的潜在分布变化导致的估计种群增长率的最大差异小于1%。我们的工作突出了个体异质性在种群水平和个体水平上的不同重要性。虽然繁殖的个体异质性可能会导致个体终身适应度的巨大差异，但改变种群中高于或低于平均水平的繁殖者的比例会导致种群年增长率的差异要小得多。对于具有稳定和高成年存活率的长寿哺乳动物，生育一个后代，繁殖中的个体异质性对种群动态的影响有限。我们认为，个体异质性对种群动态的有限影响可能是由于生活史特征的渠道化。
Identifying and accounting for unobserved individual heterogeneity in vital rates in demographic models is important for estimating population‐level vital rates and identifying diverse life‐history strategies, but much less is known about how this individual heterogeneity influences population dynamics.We aimed to understand how the distribution of individual heterogeneity in reproductive and survival rates influenced population dynamics using vital rates from a Weddell seal population by altering the distribution of individual heterogeneity in reproduction, which also altered the distribution of individual survival rates through the incorporation of our estimate of the correlation between the two rates and assessing resulting changes in population growth.We constructed an integral projection model (IPM) structured by age and reproductive state using estimates of vital rates for a long‐lived mammal that has recently been shown to exhibit large individual heterogeneity in reproduction. Using output from the IPM, we evaluated how population dynamics changed with different underlying distributions of unobserved individual heterogeneity in reproduction.Results indicate that the changes to the underlying distribution of individual heterogeneity in reproduction cause very small changes in the population growth rate and other population metrics. The largest difference in the estimated population growth rate resulting from changes to the underlying distribution of individual heterogeneity was less than 1%.Our work highlights the differing importance of individual heterogeneity at the population level compared to the individual level. Although individual heterogeneity in reproduction may result in large differences in the lifetime fitness of individuals, changing the proportion of above‐ or below‐average breeders in the population results in much smaller differences in annual population growth rate. For a long‐lived mammal with stable and high adult‐survival that gives birth to a single offspring, individual heterogeneity in reproduction has a limited effect on population dynamics. We posit that the limited effect of individual heterogeneity on population dynamics may be due to canalization of life‐history traits.