Data from: Detecting a hierarchical genetic population structure: the case study of the Fire Salamander (Salamandra salamandra) in Northern Italy

The multi-step method here applied in studying the genetic structure of a low dispersal and philopatric species, like the Fire Salamander Salamandra salamandra, was proved to be effective in identifying the hierarchical structure of population living in broadleaved forest ecosystems in Northern Italy. In this study 477 salamander larvae, collected in 28 sampling populations (SPs) in the Prealpine and in the foothill areas of Northern Italy, were genotyped at 16 specie-specific microsatellites. SPs showed a significant overall genetic variation (Global FST=0.032, p<0.001). The genetic population structure was assessed by using STRUCTURE 2.3.4. We found two main genetic groups, one represented by populations inhabiting the Prealpine belt, which maintain connections with those of the Eastern foothill lowland (PEF), and a second group with the populations of the Western foothill lowland (WF). The two groups were significantly distinct with a Global FST of 0.010 (p<0.001). While the first group showed a moderate structure, with only one divergent sampling population (Global FST =0.006, p<0.001), the second group proved more structured being divided in four clusters (Global FST=0.017, p=0.058). This genetic population structure should be due to the large conurbations and main roads that separate the WF group from the Prealpine belt and the Eastern foothill lowland. The adopted methods allowed the analysis of the genetic population structure of Fire Salamander from wide to local scale, identifying different degrees of genetic divergence of their populations derived from forest fragmentation induced by urban and infrastructure sprawl.

本研究针对低扩散能力且具恋巢性（philopatry）的物种（如火蝾螈（Fire Salamander），学名*Salamandra salamandra*）所采用的多步研究方法，经证实可有效识别意大利北部阔叶森林生态系统中种群的层级遗传结构。本研究共采集意大利北部前阿尔卑斯山区及山麓地带的28个采样种群（SPs）的477尾蝾螈幼体，对其16个物种特异性微卫星标记（microsatellites）进行基因分型。各采样种群整体呈现显著的遗传分化（整体遗传分化系数FST=0.032，p<0.001）。本研究采用STRUCTURE 2.3.4软件评估种群遗传结构，共识别出两大遗传类群：一类为栖息于前阿尔卑斯带的种群，该类群与东部山麓低地种群（PEF）存在基因交流；另一类为西部山麓低地种群（WF）。这两类群间存在显著遗传分化，整体遗传分化系数FST=0.010（p<0.001）。其中第一类群仅存在1个分化显著的采样种群（整体遗传分化系数FST=0.006，p<0.001），整体遗传结构较为松散；第二类群则具有更明显的层级结构，可进一步划分为4个遗传簇（整体遗传分化系数FST=0.017，p=0.058）。该种群遗传结构的形成，可能源于分隔西部山麓低地类群与前阿尔卑斯带、东部山麓低地类群的大型城市群及主要交通干线。本研究所采用的方法可实现火蝾螈种群遗传结构从宏观到微观尺度的解析，明确了因城市与基础设施扩张导致森林片段化所引发的种群遗传分化程度差异。