Blow to the Northeast? Intraspecific differentiation of Populus davidiana suggests a northeastward skew of a phylogeographic break boundary in East Asia

Aim: There is increasing interest in the role that biological traits, and historical and biogeographic processes, play in the formation of phylogeographic patterns. An arid belt that once existed in northern China might have affected many plants, but this has yet to be untested in an arid-tolerant, wind-dispersed species. Here we tested how intrinsic and extrinsic factors have affected the phylogeography of Populus davidiana. Location: East Asia Methods: Genetic variation was surveyed across 40 populations (555 individuals) covering the Chinese range of P. davidiana, using 16 nuclear microsatellite loci (nSSRs) and four chloroplast fragments (cpDNA). Demographic and migration hypotheses were tested using coalescent-based approaches, and the present and past potential distributions were predicted using species distribution modelling. Results: Molecular data divides P. davidiana into two lineages, northeastern China (NECR), and central and northern China (CNCR); however, the divi...研究目的：学界对生物学性状、历史与生物地理过程在谱系地理学格局（phylogeographic patterns）形成过程中的作用日益关注。中国北方历史上存在的干旱带或对诸多植物类群产生了显著影响，但针对耐干旱、风力传播物种的相关研究假说尚未得到实证检验。本研究以山杨（Populus davidiana）为研究对象，探讨内在与外在因子对其谱系地理学特征的影响。 研究区域：东亚 研究方法：本研究覆盖山杨在中国境内的分布范围，共取样40个种群（总计555个个体，采用16个核微卫星位点（nSSRs）与4个叶绿体片段（cpDNA）对其遗传变异进行系统检测。通过基于溯祖理论的分析方法验证种群动态与迁移假说，并借助物种分布模型预测该物种当前与历史潜在分布区。 研究结果：分子数据将山杨划分为两个支系：中国东北支系（NECR）与中国中部与北部支系（CNCR）；然而，其分化……