Human land transformation is one of the leading causes of vertebrate population declines. These declines are thought to be partly due to decreased connectivity and habitat loss reducing animal population sizes in disturbed habitats. With time, this can lead to declines in effective population size and genetic diversity which restrict the ability of wildlife to efficiently cope with environmental change through genetic adaptation. However, it is not well understood whether these effects generally hold across taxa. We address this question by repurposing and synthesizing raw microsatellite data from online repositories for 19 amphibian species sampled at 554 georeferenced sites in North America. For each site, we estimated gene diversity, allelic richness, effective population size, and population differentiation. Using binary urban-rural census designations, and continuous measures of human population density, the Human Footprint Index, and impervious surface cover, we tested for generalizable effects of human land use on amphibian genetic diversity. We found minimal evidence, either positive or negative, for relationships between genetic metrics and urbanization. Together with previous work on focal species that also found varying effects of urbanization on genetic composition, it seems likely that the consequences of urbanization are not easily generalizable within or across amphibian species. Questions about the genetic consequences of urbanization for amphibians should be addressed on a case-by-case basis. This contrasts with general negative effects of urbanization in mammals and consistent, but species-specific, positive and negative effects in birds.

中文翻译：

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北美城乡两栖动物种群遗传学

人类土地改造是脊椎动物种群减少的主要原因之一。这些下降被认为部分是由于连通性下降和栖息地丧失减少了受干扰栖息地中动物种群的规模。随着时间的推移，这可能导致有效种群规模和遗传多样性下降，从而限制野生动物通过遗传适应有效应对环境变化的能力。然而，尚不清楚这些影响是否普遍适用于整个分类群。我们通过重新利用和合成来自北美 554 个地理参考站点的 19 种两栖动物物种的在线存储库的原始微卫星数据来解决这个问题。对于每个位点，我们估计了基因多样性、等位基因丰富度、有效种群大小和种群分化。使用二元城乡人口普查名称，以及对人口密度、人类足迹指数和不透水地表覆盖的连续测量，我们测试了人类土地利用对两栖动物遗传多样性的普遍影响。我们发现基因指标与城市化之间关系的证据很少，无论是正面的还是负面的。再加上之前对焦点物种的研究也发现城市化对基因组成的不同影响，城市化的后果似乎不容易在两栖动物物种内部或跨物种推广。关于城市化对两栖动物的遗传后果的问题应该逐案解决。这与城市化对哺乳动物的普遍负面影响形成鲜明对比，并且持续但具有物种特异性，