Invasive mammals such as rats are associated with negative impacts on native fauna and their eradication on islands around the world has been proved to result in substantial conservation gains. Fernando de Noronha is an archipelago located off the north-east coast of Brazil and has records of native fauna negatively impacted by introduced rats. We used D-Loop sequences and 14 microsatellite markers to investigate gene flow between three populations of Rattus rattus across two islands of Fernando de Noronha. Using both methods we found very great differentiation between the two islands, indicating very low or no gene flow. Our findings suggested if Rata Island were cleared of rats it would have a low probability of reinvasion occurring from the main island. Thus, we recommend an eradication program be implemented on Rata Island following the successful program on nearby Meio Island.

入侵性哺乳动物（如大鼠）对本地动物群有负面影响，其根除在世界各地的岛屿上已被证明可以带来巨大的保护收益。费尔南多·迪诺罗尼亚群岛（Fernando de Noronha）是位于巴西东北海岸的一个群岛，并且有受到引入的老鼠负面影响的本地动物记录。我们使用D-Loop序列和14个微卫星标记来研究三只褐家鼠之间的基因流跨越费尔南多·迪诺罗尼亚群岛的两个岛屿。使用这两种方法，我们发现两个岛之间的差异非常大，表明基因流量非常低或没有。我们的发现表明，如果清除Rata岛上的老鼠，则从主岛发生入侵的可能性很小。因此，我们建议在附近的美浓岛成功实施根除计划之后，在拉塔岛实施一项根除计划。