Data from: Comparative landscape genetics of pond-breeding amphibians in Mediterranean temporal wetlands: the positive role of structural heterogeneity in promoting gene flow

Comparative landscape genetics studies can provide key information to implement cost-effective conservation measures favoring a broad set of taxa. These studies are scarce, particularly in Mediterranean areas, which include diverse but threatened biological communities. Here we focus on Mediterranean wetlands in central Iberia and perform a multi-level, comparative study of two endemic pond-breeding amphibians, a salamander (Pleurodeles waltl) and a toad (Pelobates cultripes). We genotyped 411 salamanders from 20 populations and 306 toads from 16 populations at 18 and 16 microsatellite loci, respectively, and identified major factors associated with population connectivity through the analysis of three sets of variables potentially affecting gene flow at increasingly finer levels of spatial resolution. Topographic, land use/cover, and remotely sensed vegetation/moisture indices were used to derive optimized resistance surfaces for the two species. We found contrasting patterns of genetic structure, with stronger, finer-scale genetic differentiation in Pleurodeles waltl, and notable differences in the role of fine-scale patterns of heterogeneity in vegetation cover and water content in shaping patterns of regional genetic structure in the two species. Overall, our results suggest a positive role of structural heterogeneity in population connectivity in pond-breeding amphibians, with habitat patches of Mediterranean scrubland and open oak woodlands (“dehesas”) facilitating gene flow. Our study highlights the usefulness of remotely sensed continuous variables of land cover, vegetation and water content (e.g., NDVI, NDMI) in conservation-oriented studies aimed at identifying major drivers of population connectivity.

比较景观遗传学研究可为实施惠及多类生物类群的高性价比保护措施提供关键依据。此类研究较为匮乏，尤其在兼具多样受威胁生物群落的地中海区域。本研究聚焦伊比利亚半岛中部的地中海湿地，针对两种特有静水繁殖两栖类——魏氏肋突螈（Pleurodeles waltl）和锄足蟾（Pelobates cultripes）开展多尺度比较研究。我们分别基于18个和16个微卫星位点（microsatellite loci），对来自20个种群的411尾魏氏肋突螈以及来自16个种群的306只锄足蟾进行基因分型，并通过分析三组潜在影响基因流的变量，采用逐级细化的空间分辨率筛选出与种群连通性相关的关键驱动因子。研究借助地形、土地利用/覆被及遥感植被/湿度指数，为两个物种构建了优化的阻力面（resistance surfaces）。结果显示，两个物种的遗传结构（genetic structure）模式存在显著差异：魏氏肋突螈呈现更强、更精细尺度的遗传分化（genetic differentiation），且二者在植被覆被与含水量的精细尺度异质性模式对区域遗传结构的塑造作用上存在显著区别。总体而言，本研究结果表明，结构异质性对静水繁殖两栖类的种群连通性具有积极作用，地中海灌丛与开放式栎林（德赫萨，"dehesas"）生境斑块可促进基因流。本研究凸显了土地覆被、植被与含水量的遥感连续变量（如归一化植被指数（NDVI）、归一化湿度指数（NDMI））在旨在识别种群连通性关键驱动因子的保护导向研究中的应用价值。