Data from: Urban landscape genetics: canopy cover predicts gene flow between white-footed mouse (Peromyscus leucopus) populations in New York City

In this study, I examine the influence of urban canopy cover on gene flow between 15 white-footed mouse (Peromyscus leucopus) populations in New York City. Nm calculated from F_ST and recent migration estimated in BayesAss+, but not historic migration estimated in Migrate-n, exhibited significant isolation-by-distance (IBD). Gene flow was also associated with “effective distances” between populations that were calculated based on percent canopy cover using two different approaches: 1) isolation-by-effective-distance (IED) that calculates the single best pathway to minimize passage through high-resistance (i.e. low canopy cover) areas, and 2) isolation-by-resistance (IBR), an implementation of circuit theory that identifies all low-resistance paths through the landscape. IBR, but not IED, models were still significantly associated with all three measures of gene flow after factoring out the influence of IBD using partial Mantel tests. In cases where both IBR and IED explained gene flow independently of IBD, an additional partial Mantel test indicated that the IBR models still explained gene flow after factoring out IED. The IBR models that explained the most variation in recent migration after factoring out IBD (r = 0.70 – 0.90) included landscape cells with at least 60-80% canopy cover as low resistance habitat. These results have implications for understanding the impacts of urbanization trends on native wildlife, as well as for urban reforestation efforts that aim to improve urban ecosystem processes.本研究探讨了城市冠层覆盖度对纽约市15个白足鼠（Peromyscus leucopus）种群间基因流的影响。由F_ST计算得到的种群迁移数（Nm）以及在BayesAss+软件中估算的近期迁移率均表现出显著的距离隔离（isolation-by-distance, IBD）效应，而Migrate-n软件中估算的历史迁移率则未呈现该效应。基因流还与基于冠层覆盖百分比、通过两种不同方法计算得到的种群间有效距离相关：其一为有效距离隔离（isolation-by-effective-distance, IED），即测算可最小化穿越高阻力（即低冠层覆盖区域）区域的最优单一通路；其二为抗性隔离（isolation-by-resistance, IBR），即基于电路理论的分析方法，可识别景观中所有低阻力通路。通过偏曼特尔检验（partial Mantel tests）控制距离隔离的影响后，抗性隔离模型仍与全部三种基因流度量指标显著相关，而有效距离隔离模型则无此关联；在有效距离隔离与抗性隔离均能独立于距离隔离解释基因流的案例中，额外的偏曼特尔检验显示，在剔除有效距离隔离的效应后，抗性隔离模型仍可解释基因流。在控制距离隔离效应的前提下，对近期迁移率变异解释度最高的抗性隔离模型（相关系数r=0.70–0.90）将冠层覆盖度至少60%~80%的景观单元界定为低阻力生境。本研究结果可为理解城市化趋势对本土野生动物的影响提供参考，同时也为旨在改善城市生态系统过程的城市再造林工作提供理论依据。