Riecke Thomas V, Fay Rémi, Hegelbach Johann, Ravussin Pierre-Alain, Arrigo Daniel, Schaub Michael
Swiss Ornithological Institute, Sempach, Switzerland.
Wildlife Biology Program, Department of Ecosystem and Conservation Science, University of Montana, Missoula, Montana, USA.
Ecology. 2025 Aug;106(8):e70161. doi: 10.1002/ecy.70161.
Understanding the drivers of fitness is a key goal of population and evolutionary ecology. However, measuring individual variation in demographic components in imperfectly observed populations of wild organisms is extremely challenging. Recent research has demonstrated that estimates of fixed individual variation in Bernoulli variables (e.g., survival and breeding propensity) are often unreliable in the face of imperfect detection and small sample sizes. Thus, we demonstrate the use of structural equation modeling approaches to simultaneously estimate latent variation in demographic performance and link said variation to individual demographic components. We demonstrate the use of this approach with 30+ year capture-recapture datasets collected on two passerine species (white-throated dipper, Cinclus cinclus, and pied flycatcher, Ficedula hypoleuca) and simultaneously estimate latent variation in individual quality and age-specific variation in demographic components. We found senescent decline in survival and fecundity in both species and demonstrated strong among-individual heterogeneity in demographic performance. Notably, the residual reproductive value of older individuals of higher quality was greater than younger individuals of reduced and average quality. We demonstrate that this approach may be useful in a variety of situations, discuss its limitations, and make suggestions for future research.
了解适合度的驱动因素是种群与进化生态学的一个关键目标。然而，在对野生生物进行不完全观测的种群中测量个体在人口统计学组成部分上的差异极具挑战性。近期研究表明，在存在不完全检测和小样本量的情况下，对伯努利变量（如生存和繁殖倾向）中固定个体差异的估计往往不可靠。因此，我们展示了如何使用结构方程建模方法来同时估计人口统计学表现中的潜在差异，并将这种差异与个体人口统计学组成部分联系起来。我们利用在两种雀形目鸟类（白喉河乌，Cinclus cinclus，和斑姬鹟，Ficedula hypoleuca）上收集的30多年的标记重捕数据集展示了这种方法的应用，并同时估计了个体质量的潜在差异以及人口统计学组成部分的年龄特异性差异。我们发现这两个物种的生存和繁殖力都出现了衰老下降，并证明了在人口统计学表现上存在强烈的个体间异质性。值得注意的是，高质量老年个体的剩余繁殖价值大于低质量和中等质量的年轻个体。我们证明了这种方法在各种情况下可能都有用，讨论了其局限性，并对未来研究提出了建议。
