The riverine barrier hypothesis (RBH) posits that rivers comprise geographical barriers to gene flow for terrestrial organisms, thus promoting genetic differentiation between populations. Here, we explored the RBH on larviparous and pueriparous populations of the live-bearing fire salamander (Salamandra salamandra). While larviparous fire salamanders exhibit a semi-aquatic life cycle (females deposit pre-metamorphic larvae on water), pueriparous salamanders present a fully terrestrial life cycle (females deliver terrestrial juveniles) and, therefore, a greater independence from water for survival and reproduction. We performed a fine-scale sampling of opposite transects in 11 rivers (six and five for larviparous and pueriparous populations, respectively) to test the hypothesis that rivers are more effective barriers for pueriparous salamanders due to their terrestrial life cycle. We carried out individual- and population-based genetic analyses using 14 microsatellites and a mitochondrial marker to examine the extent to which rivers hinder short- and long-term gene flow. We found that rivers are semi-permeable obstacles for both larviparous and pueriparous salamanders, although they appear to be more effective barriers for the latter when rivers with similar attributes are compared. We also found that river width and possibly the presence of crossing structures may influence the genetic barrier effects of rivers in fire salamanders. This is one of the very few studies in amphibians showing how different reproductive strategies influence the barrier effects imposed by rivers.

河流障碍假设（RBH）认为，河流构成了陆地生物基因流动的地理障碍，从而促进了种群之间的遗传分化。在这里，我们研究了活火火sal（Salamandra salamandra）的幼虫和产卵种群的RBH）。幼虫火sal显示出半水生生命周期（雌性在水上沉积前变态幼虫），而pu生火蜥蜴则呈现出完整的陆地生命周期（雌性传递陆生幼体），因此在生存和繁殖方面与水的独立性更高。我们在11条河流中进行了相反样面的精细采样（对于幼虫和粉虱种群分别为6条和5条），以检验以下假设：由于河流的陆地生命周期，河流是更有效的对sal的屏障。我们使用14个微卫星和线粒体标记物进行了基于个体和人群的遗传分析，以研究河流阻碍短期和长期基因流量的程度。我们发现，河流是幼虫和产卵sal的半渗透性障碍，尽管在比较具有相似属性的河流时，它们似乎是后者的更有效屏障。我们还发现河流宽度和可能存在的交叉结构可能会影响火sal中河流的遗传屏障效应。这是两栖动物中为数不多的研究之一，研究表明不同的繁殖策略如何影响河流施加的屏障效应。