Data from: Phylogeographic concordance factors quantify phylogeographic congruence among co-distributed species in the Sarracenia alata pitcher plant system

Comparative phylogeographic investigations have identified congruent phylogeographic breaks in co-distributed species in nearly every region of the world. The qualitative assessments of phylogeographic patterns traditionally used to identify such breaks, however, are limited because they rely on identifying monophyletic groups across species and do not account for coalescent stochasticity. Only long-standing phylogeographic breaks are likely to be obvious; many species could have had a concerted response to more recent landscape events, yet possess subtle signs of phylogeographic congruence because ancestral polymorphism has not completely sorted. Here we introduce Phylogeographic Concordance Factors (PCFs), a novel method for quantifying phylogeographic congruence across species. We apply this method to the <i>Sarracenia alata</i> pitcher plant system, a carnivorous plant with a diverse array of commensal organisms. We explore whether a group of ecologically associated arthropods have co-diversified with the host pitcher plant, and identify if there is a positive correlation between ecological interaction and PCFs. Results demonstrate that multiple arthropods share congruent phylogeographic breaks with <i>S. alata</i>, and provide evidence that the level of ecological association can be used to predict the degree of similarity in the phylogeographic pattern. This study outlines an approach for quantifying phylogeographic congruence, a central concept in biogeographic research.比较系统地理学研究已在全球几乎所有区域的同域分布物种中发现了一致的系统地理断裂带。然而，传统上用于识别此类断裂带的系统地理格局定性评估方法存在局限：此类方法依赖跨物种的单系群识别，且未考虑溯祖随机性。唯有长期存在的系统地理断裂带才较为直观；诸多物种或许曾对近期发生的地表事件产生协同响应，但由于祖先多态性尚未完全分选，仅表现出微弱的系统地理一致性特征。本研究提出系统地理一致性因子（Phylogeographic Concordance Factors, PCFs），这是一种可量化跨物种种群系统地理一致性的全新方法。我们将该方法应用于黄瓶子草（Sarracenia alata）食虫植物体系——该类群拥有丰富多样的共栖生物类群。本研究旨在探究一类与宿主存在生态关联的节肢动物是否与该食虫植物发生了协同分化，并验证生态互作强度与PCFs值之间是否存在正相关关系。研究结果显示，多种节肢动物与黄瓶子草（S. alata）拥有一致的系统地理断裂带，并证实生态关联强度可用于预测系统地理格局的相似程度。本研究构建了一套量化系统地理一致性的研究框架，而系统地理一致性是生物地理学研究的核心概念之一。