Patterns, sources, and consequences of variation in age‐specific vital rates: Insights from a long‐term study of Weddell seals
Patterns, sources, and consequences of variation in age‐specific vital rates: Insights from a long‐term study of Weddell seals
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特定年龄生命率变化的模式、来源和后果：对威德尔海豹的长期研究的见解
DOI：
10.1111/1365-2656.13870
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发表时间：
2023
影响因子：
4.8
通讯作者：
Rotella, Jay J.
中科院分区：
文献类型：
--
作者：
Rotella, Jay J.
种群中个体的生殖和生存能力的变化在自然界中普遍存在，是个体适应性的关键，并影响种群动态，这导致人们对理解生命率变化的原因和后果产生了浓厚的兴趣。对于长寿的物种，对已知年龄个体的大样本进行长期研究是评估生命率变化的理想选择。自20世纪60年代以来，南极洲埃里伯斯湾的威德尔海豹种群一直在每年南方春季进行研究。自1982年以来，每年对所有新生儿进行标记，并每年进行多次捕获标记再捕获（CMR）调查。在过去的20年中，通过利用该项目长期CMR数据和可用分析方法的稳步改进，在早期研究结果的基础上进行了一系列分析。在这里，我总结了与女性特定年龄的生命率变化相关的四个主要主题的进展：早期生存和首次生育年龄，生育成本，人口缓冲和人口老化。多状态模型发现，首次生育年龄变化很大（4-14岁），并确定了母亲年龄对后代生存和招募率的对比影响。随后对招募后的女性数据进行分析，发现生存和未来生殖的生殖成本，并提供了人口缓冲的有力证据。最近的研究结果表明，生命率存在重要的个体间差异，并揭示了生殖和生存衰老的对比模式。生命率的变化来源包括年龄，生殖状态，年份和个体。运气和个体质量的结合导致个体适应性结果的强烈变化：种群中出生的约80%的雌性不产生后代，其余20%在一生的生殖输出中变化很大（范围：1-23只幼仔）。需要进一步研究，以确定导致生命率每年变化的具体环境条件，并更好地了解个体的起源。异质性还需要更好地量化运气、母体效应和环境条件对生命率变化的相对作用，并了解这种变化对后代人口统计学表现和整体人口动态的重要性。
Variations in the reproductive and survival abilities of individuals within a population are ubiquitous in nature, key to individual fitness, and affect population dynamics, which leads to strong interest in understanding causes and consequences of vital‐rate variation. For long‐lived species, long‐term studies of large samples of known‐age individuals are ideal for evaluating vital‐rate variation.A population of Weddell seals in Erebus Bay, Antarctica, has been studied each Austral spring since the 1960s. Since 1982, all newborns have been tagged each year and multiple capture‐mark‐recapture (CMR) surveys have been conducted annually.Over the past 20 years, a series of analyses have built on results of earlier research by taking advantage of steady improvements in the project's long‐term CMR data and available analytical methods. Here, I summarize progress made on four major topics related to variation in age‐specific vital rates for females: early‐life survival and age at first reproduction, costs of reproduction, demographic buffering, and demographic senescence.Multistate modelling found that age at first reproduction varies widely (4–14 years of age) and identified contrasting influences of maternal age on survival and recruitment rates of offspring. Subsequent analyses of data for females after recruitment revealed costs of reproduction to both survival and future reproduction and provided strong evidence of demographic buffering. Recent results indicated that important levels of among‐individual variation exist in vital rates and revealed contrasting patterns for senescence in reproduction and survival.Sources of variation in vital rates include age, reproductive state, year, and individual. The combination of luck and individual quality results in strong variation in individual fitness outcomes: ~80% of females born in the population produce no offspring, and the remaining 20% vary strongly in lifetime reproductive output (range: 1–23 pups).Further research is needed to identify the specific environmental conditions that lead to annual variation in vital rates and to better understand the origins of individual heterogeneity. Work is also needed to better quantify the relative roles of luck, maternal effects, and environmental conditions on variation in vital rates and to learn the importance of such variation to demographic performance of offspring and on overall population dynamics.