Data from: Testing the efficiency of nested barriers to dispersal in the Mediterranean high mountain plant Edraianthus graminifolius (Campanulaceae)

Due to strong spatial heterogeneity and limited Pleistocene glaciation, the Balkan Peninsula is a major European biodiversity hotspot. Surprisingly little, however, is known about patterns and processes of intraspecific diversification of its biota in general and of high altitude species in particular. A well-suited system to test hypotheses with respect to various isolating factors acting at different geographic scales and to explore full-range phylogeographic patterns on the Balkan Peninsula is Edraianthus graminifolius (Campanulaceae), distributed in the western Balkan mountain systems, the southwestern Carpathians and the Apennine Peninsula. To this end, we used a dense population sampling and employed Amplified Fragment Length Polymorphism (AFLP) markers and plastid DNA sequences supplemented by ecological niche modelling. The strongest splits were inferred to separate southern and northern Balkan populations from the central ones, from where range extension occurred to the Carpathians and, in more recent times, once or twice to the Apennine Peninsula. The three genetic groups in the western Balkan Peninsula were remarkably congruent among molecular markers suggesting that the barriers to gene flow acted over long time periods facilitating allopatric differentiation. Each main group of Balkan populations contained genetically and geographically distinct subgroups, which likely are the result of local refugia during warmer periods. Evidently, the topographically highly complex and during the last glacial maximum only locally glaciated Balkan Peninsula is a hotspot of species richness and endemism as well as a sanctuary of intraspecific genetic diversity, even if the underlying causes remain insufficiently understood.

受强烈空间异质性与有限的更新世（Pleistocene）冰川作用影响，巴尔干半岛是欧洲重要的生物多样性热点地区。然而，目前学界对该半岛生物群整体的种内分化模式与过程，尤其是高海拔物种的相关研究仍十分匮乏。分布于巴尔干半岛西部山地、喀尔巴阡山脉西南部以及亚平宁半岛的草原岩风铃（*Edraianthus graminifolius*，风铃草科（Campanulaceae）），是检验不同地理尺度隔离因子假说、探究巴尔干半岛全域系统地理格局的理想研究体系。为此，本研究采用高密度种群取样策略，结合扩增片段长度多态性（Amplified Fragment Length Polymorphism, AFLP）分子标记、质体DNA（plastid DNA）序列分析，并辅以生态位模型（ecological niche modelling）开展研究。研究推断，最显著的遗传分化将巴尔干半岛的南部、北部种群与中部种群分隔开来；中部种群是向喀尔巴阡山脉扩散的起源，而在更近的地质时期，又曾1至2次向亚平宁半岛扩张。巴尔干半岛西部的三个遗传类群在不同分子标记下表现出高度一致的结果，这表明基因流阻隔长期存在，推动了异域分化（allopatric differentiation）过程。巴尔干半岛的每个主要种群类群均包含遗传与地理特征均显著分化的亚类群，这大概率是温暖时期局部避难所（refugia）作用的产物。显然，地形高度复杂且末次冰盛期仅存在局部冰川作用的巴尔干半岛，既是物种丰富度与特有性的热点区域，也是种内遗传多样性的庇护所，尽管其背后的具体机制仍未被充分阐明。