Variation in the vital rates of an Antarctic marine predator: the role of individual heterogeneity
Variation in the vital rates of an Antarctic marine predator: the role of individual heterogeneity
复制标题
南极海洋捕食者生命率的变化：个体异质性的作用
DOI：
10.1002/ecy.2481
复制
发表时间：
2018
期刊：
影响因子：
4.8
通讯作者：
Garrott, Robert
中科院分区：
文献类型：
--
作者：
Paterson, J. Terrill;Rotella, Jay. J.;Link, William A.;Garrott, Robert
生活史特征的变化，如寿命和终生生殖输出，被认为部分是由于生存和生殖的潜在概率的个体差异。然而，人口统计过程的随机性也会在其他方面相同的个体之间产生相当大的健身相关特征变化。因此，对生活史进化和种群动态的更好理解取决于评估这些过程中每一个的相对作用。在这里，我们使用了来自南极洲埃里伯斯湾的1，274只雌性威德尔海豹的33年生殖历史数据集，以评估生存和生殖概率个体间异质性的证据强度，同时考虑到生命率变化的多种其他来源。我们的分析使用贝叶斯模型选择技术和诊断的最新进展，直接比较模型拟合和模型之间的预测能力，包括对生存和繁殖的个体影响。我们发现了强有力的证据证明繁殖成本对生存和未来繁殖的影响，繁殖者的生存率和随后的繁殖率比非繁殖者低3%和6%。我们检测到存活率和繁殖率的年龄相关变化，但两种比率的模式不同。存活率从7岁时的0.92稳步下降到最大年龄31岁时的0.56。相反，生育率从7岁的0.68上升到16岁的0.79，然后稳步下降到0.37。包括个体效应的模型解释了观察到的生活史的更多变化，并且比那些没有的模型具有更好的估计预测能力，这表明它们在理解个体生活史特征的变异来源方面的重要性。我们发现，相对于生殖而言，生存的个体间异质性较小。我们的研究发现，生命率的变化模式与生活史理论的一系列预测一致，这是第一个对长寿，高纬度海洋哺乳动物的重要生命率变化进行全面评估，同时充分利用模型评估的最新发展。
Variation in life‐history traits such as lifespan and lifetime reproductive output is thought to arise, in part, due to among‐individual differences in the underlying probabilities of survival and reproduction. However, the stochastic nature of demographic processes can also generate considerable variation in fitness‐related traits among otherwise‐identical individuals. An improved understanding of life‐history evolution and population dynamics therefore depends on evaluating the relative role of each of these processes. Here, we used a 33‐yr data set with reproductive histories for 1,274 female Weddell seals from Erebus Bay, Antarctica, to assess the strength of evidence for among‐individual heterogeneity in the probabilities of survival and reproduction, while accounting for multiple other sources of variation in vital rates. Our analysis used recent advances in Bayesian model selection techniques and diagnostics to directly compare model fit and predictive power between models that included individual effects on survival and reproduction to those that did not. We found strong evidence for costs of reproduction to both survival and future reproduction, with breeders having rates of survival and subsequent reproduction that were 3% and 6% lower than rates for non‐breeders. We detected age‐related changes in the rates of survival and reproduction, but the patterns differed for the two rates. Survival rates steadily declined from 0.92 at age 7 to 0.56 at the maximal age of 31 yr. In contrast, reproductive rates increased from 0.68 at age 7 to 0.79 at age 16 and then steadily declined to 0.37 for the oldest females. Models that included individual effects explained more variation in observed life histories and had better estimated predictive power than those that did not, indicating their importance in understanding sources of variation among individuals in life‐history traits. We found that among‐individual heterogeneity in survival was small relative to that for reproduction. Our study, which found patterns of variation in vital rates that are consistent with a series of predictions from life‐history theory, is the first to provide a thorough assessment of variation in important vital rates for a long‐lived, high‐latitude marine mammal while taking full advantage of recent developments in model evaluation.