Department of Biology, Biosciences Complex, Queen's University, Kingston, ON, Canada.
Department of Mathematics and Statistics, Queen's University, Kingston, ON, Canada.
Ecol Lett. 2021 Oct;24(10):2282-2297. doi: 10.1111/ele.13843. Epub 2021 Jul 19.
Among-individual variation in vital rates, such as mortality and birth rates, exists in nearly all populations. Recent studies suggest that this individual heterogeneity produces substantial life-history and fitness differences among individuals, which in turn scale up to influence population dynamics. However, our ability to understand the consequences of individual heterogeneity is limited by inconsistencies across conceptual frameworks in the field. Studies of individual heterogeneity remain filled with contradicting and ambiguous terminology that introduces risks of misunderstandings, conflicting models and unreliable conclusions. Here, we synthesise the existing literature into a single and comparatively straightforward framework with explicit terminology and definitions. This work introduces a distinction between potential vital rates and realised vital rates to develop a coherent framework that maps directly onto mathematical models of individual heterogeneity. We suggest the terms "fixed condition" and "dynamic condition" be used to distinguish potential vital rates that are permanent from those that can change throughout an individual's life. To illustrate, we connect the framework to quantitative genetics models and to common classes of statistical models used to infer individual heterogeneity. We also develop a population projection matrix model that provides an example of how our definitions are translated into precise quantitative terms.
个体间的生命表参数（如死亡率和出生率）存在于几乎所有的种群中。最近的研究表明，这种个体异质性在个体之间产生了大量的生活史和适应度差异，进而影响了种群动态。然而，我们理解个体异质性的能力受到该领域概念框架不一致的限制。个体异质性的研究仍然充斥着相互矛盾和模糊的术语，这带来了误解、冲突模型和不可靠结论的风险。在这里，我们将现有的文献综合成一个单一的、相对简单的框架，使用明确的术语和定义。这项工作区分了潜在生命表参数和实现生命表参数，以建立一个连贯的框架，该框架直接映射到个体异质性的数学模型上。我们建议使用“固定条件”和“动态条件”这两个术语来区分个体在其整个生命周期中保持不变的潜在生命表参数和可能发生变化的潜在生命表参数。举例来说，我们将框架与数量遗传学模型以及用于推断个体异质性的常见统计模型类别联系起来。我们还开发了一个种群投影矩阵模型，该模型提供了一个示例，说明我们的定义是如何转化为精确的定量术语的。
