Data from: Limited influence of local and landscape factors on finescale gene flow in two pond-breeding amphibians

Dispersal and gene flow within animal populations are influenced by the composition and configuration of the landscape. In this study, we evaluated hypotheses about the impact of natural and anthropogenic factors on genetic differentiation in two amphibian species, the spotted salamander (Ambystoma maculatum) and the wood frog (Lithobates sylvaticus) in a commercial forest in central Maine. We conducted this analysis at two scales: a local level, focused on factors measured at each breeding pond and a landscape level, focused on factors measured between ponds. We investigated the effects of a number of environmental factors in 6 categories including Productivity, Physical, Land Composition, Land Configuration, Isolation, and Location. We also investigated the relationship of landscape composition and configuration on gene flow. Embryos were sampled from 56 spotted salamander breeding ponds and 39 wood frog breeding ponds. We used a hierarchical Bayesian approach in the program GESTE at each breeding pond and a random forest algorithm in conjunction with a network analysis between the ponds. We found overall high genetic connectivity across distances up to 17 km for both species and a limited effect of natural and anthropogenic factors on gene flow. We found the null models best explained patterns of genetic differentiation at a local level, and found several factors at the landscape level that weakly influenced gene flow. This research indicates multi-scale investigations that incorporate local and landscape factors are valuable for understanding patterns of gene flow. Our findings suggest that dispersal rates in this system are high enough to minimize genetic structuring, and that current forestry practices do not significantly impede dispersal.

动物种群内的扩散与基因流（gene flow）受景观格局的组成与配置影响。本研究针对缅因州中部一片商品林中的两种两栖动物——斑点钝口螈（Ambystoma maculatum）与林蛙（Lithobates sylvaticus），评估了自然与人为因子对其遗传分化（genetic differentiation）影响的相关假说。本次分析设置两个尺度展开：局部尺度聚焦于各繁殖池塘（breeding pond）的实测因子，景观尺度则聚焦于池塘间的实测因子。我们共研究了6类环境因子的效应，分别为生产力、物理因子、土地组成、土地配置、隔离度与区位。此外，我们还探究了景观组成与配置对基因流的影响关系。研究共从56个斑点钝口螈繁殖池塘与39个林蛙繁殖池塘中采集了胚胎样本。我们针对各繁殖池塘使用程序GESTE中的分层贝叶斯（hierarchical Bayesian）方法，并结合随机森林算法（random forest algorithm）与池塘间的网络分析（network analysis）完成本次分析。研究结果显示，两种物种在最远17公里的范围内均表现出较高的遗传连通性（genetic connectivity），自然与人为因子对基因流的影响整体有限。局部尺度上，零模型（null models）最能解释遗传分化格局；而景观尺度上则存在若干对基因流影响较弱的因子。本研究表明，结合局部与景观因子的多尺度调查，对于解析基因流格局具有重要价值。研究结果显示，该研究系统中的扩散速率足以抑制遗传结构（genetic structuring）的形成，且当前林业经营活动并未对扩散过程造成显著阻碍。