Data from: Effect of the landscape matrix on gene flow in a coastal amphibian metapopulation

Functional connectivity is crucial for the persistence of a metapopulation, because migration among subpopulations enables recolonization and counteracts genetic drift, which is especially important in small subpopulations. We studied the degree and drivers of connectivity among occupied patches of a coastal dune metapopulation of the Natterjack Toad (Epidalea calamita Laurenti), on the basis of microsatellite variation. As spatial landscape heterogeneity is expected to influence dispersal and genetic structure, we analyzed which landscape features affect functional connectivity and to what extent. Sixty different landscape resistance scenarios as well as the isolation-by-distance model were compared using two landscape genetics approaches. We identified three subpopulations with unidirectional levels of gene flow among the two most geographically separated subpopulations, while inferred gene flow into the geographically intermediate subpopulation was limited. Urbanization and vegetation height negatively affected connectivity. Low estimates of genetic diversity and effective population size indicate that conservation measures in the smallest and most isolated subpopulation are required.

功能连通性（functional connectivity）是集合种群（metapopulation）存续的关键要素，亚种群间的迁移不仅能够促成空斑块的重新定植，还可抵消遗传漂变（genetic drift）的负面影响——这一点在小型亚种群中尤为重要。本研究基于微卫星变异（microsatellite variation），针对黄条背蟾蜍（Epidalea calamita Laurenti）的滨海沙丘集合种群的占据斑块，探究了其连通性程度及其驱动因子。鉴于空间景观异质性（spatial landscape heterogeneity）会对扩散过程与遗传结构（genetic structure）产生影响，我们分析了哪些景观特征会作用于功能连通性，以及其影响强度如何。我们采用两种景观遗传学方法（landscape genetics approaches），对共计60种不同的景观抗性情景（landscape resistance scenarios）与距离隔离模型（isolation-by-distance model）进行了比较。我们共识别出三个亚种群：地理间隔最远的两个亚种群间存在单向基因流（gene flow），而向地理中间亚种群的推断基因流则较为有限。城市化与植被高度会对连通性产生负面影响。较低的遗传多样性（genetic diversity）与有效种群大小（effective population size）估算值表明，需针对该种群中最小且最孤立的亚种群采取保护措施（conservation measures）。