AimPagel's (lambda) is a useful tool in ecology and evolution for describing trait evolution, imputing missing species' data, and generalising ecological relationships beyond their study system. Here, we review the various applications and interpretations of , highlight common misconceptions, and show how confusion in defining and using can mislead our interpretation of ecological and evolutionary processes.InnovationWe highlight that: (1) as an index of phylogenetic signal applied to continuous traits, typically (but not always) ranges between 0 and 1, and is a rate‐independent measure of the degree to which closely‐related species resemble one‐another relative to a Brownian motion expectation. (2) estimated on incompletely sampled clades assumes random species sampling, which is rarely the case in ecological data sets, and likely has large uncertainty. (3) High is a necessary but not sufficient prerequisite for phylogenetic imputation. (4) in Phylogenetic Generalised Least Squares (PGLS) models is estimated using model residuals and is not (in most cases) an index of phylogenetic signal of measured traits. (5) New hierarchical methods including intra‐specific variation return metrics such as that are similar but not identical to ; we show how these disparate approaches can be unified within a single framework.Main ConclusionsPhylogenetic methods are increasingly integrated into ecological and evolutionary analyses. Pagel's , a phylogenetic scaling parameter that describes how shared evolutionary history structures species similarities and differences, is commonly used as both a metric of ‘phylogenetic signal’ and as a statistical correction for the evolutionary non‐independence of species in phylogenetic comparative analysis. We show how to use to resolve these conceptual and statistical discrepancies.

中文翻译：

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如何在《生态学与进化》中定义、使用和解释 Pagel 的 λ$$ \lambda $$ （Lambda）


AimPagel （lambda） 是生态学和进化论中的有用工具，用于描述性状进化、估算缺失物种的数据以及推广其研究系统之外的生态关系。在这里，我们回顾了 的各种应用和解释，强调了常见的误解，并展示了定义和使用中的混淆如何误导我们对生态和进化过程的解释。创新我们强调：（1） 作为应用于连续性状的系统发育信号指数，通常（但并非总是）范围在 0 到 1 之间，并且是与速率无关的量度，用于衡量密切相关物种相对于布朗运动期望的相似程度。（2） 对不完全采样的分支进行估计假设随机物种采样，这在生态数据集中很少见，并且可能具有很大的不确定性。（3） 高是系统发育插补的必要但不是充分的先决条件。（4） 在系统发育中，广义最小二乘法 （PGLS） 模型是使用模型残差估计的，而不是（在大多数情况下）测量性状的系统发育信号指数。（5） 新的分层方法，包括种内变异返回指标，例如相似但不相同的指标;我们展示了如何在单个框架中统一这些不同的方法。主要结论系统发育方法越来越多地被整合到生态学和进化分析中。Pagel 是一个系统发育尺度参数，描述共享进化历史如何构建物种的相似性和差异性，通常用作“系统发育信号”的指标，以及系统发育比较分析中物种进化非独立性的统计校正。 我们将展示如何解决这些概念和统计差异。