Landscape genetics reveals unique and shared effects of urbanization for two sympatric pool-breeding amphibians

Metapopulation-structured species can be negatively affected when landscape fragmentation impairs connectivity. We investigated the effects of urbanization on genetic diversity and gene flow for two sympatric amphibian species, spotted salamanders (Ambystoma maculatum) and wood frogs (Lithobates sylvaticus), across a large (>35,000 km2) landscape in Maine, USA, containing numerous natural and anthropogenic gradients. Isolation by distance (IBD) patterns differed between the species. Spotted salamanders showed a linear and relatively high variance relationship between genetic and geographic distance (r = 0.057; p < 0.001); whereas, wood frogs exhibited a strongly non-linear and lower variance relationship (r = 0.429; p < 0.001). Scale dependence analysis of IBD found gene flow has its most predictable influence (strongest IBD correlations) at distances up to 9 km for spotted salamanders and up to 6 km for wood frogs. Estimated effective migration surfaces revealed contrasting pa...

当景观破碎化损害连通性时，具有集合种群（metapopulation）结构的物种种群会受到负面影响。本研究以美国缅因州一片面积超35000平方千米、涵盖众多自然与人为环境梯度的景观为研究区域，探究了城市化对两种同域两栖动物——斑点钝口螈（Ambystoma maculatum）和林蛙（Lithobates sylvaticus）的遗传多样性与基因流的影响。两种物种的距离隔离（Isolation by distance, IBD）模式存在显著差异：斑点钝口螈的遗传距离与地理距离呈线性相关，且变异程度相对较高（r=0.057；p<0.001）；而林蛙则表现出强烈的非线性相关关系，且变异程度较低（r=0.429；p<0.001）。对距离隔离的尺度依赖性分析结果显示，基因流的可预测性最强（即距离隔离相关性最高）的空间尺度范围分别为：斑点钝口螈不超过9千米，林蛙不超过6千米。基于有效迁移表面的估算结果揭示了二者迥异的……