In response to the striking effects of environmental change, conservation strategies often include the identification of conservation areas that can effectively maintain vulnerable species. Consequently, identifying system-specific conditions that maintain the demographic and genetic viability of species of conservation concern is essential. Connectivity plays a critical role in the persistence of populations. Islands have been model systems to understand connectivity and metapopulation processes and have emerged as particularly favorable targets for conservation. While islands can be isolated from mainland disturbances, it is unknown what degree of isolation is necessary to avoid unfavorable changes but remain sufficiently connected to maintain population viability. To test this question, we explored connectivity within the Apostle Islands, an archipelago of 22 islands within Lake Superior, by comparing historical and contemporary trends in ice bridge connectivity and by simulating the effect of reduced connectivity within this system. We developed a demographically informed individual-based model to explicitly test the role of connectivity to influence the persistence and genetic diversity of American marten Martes americana, a forest carnivore at risk across its southern range boundary. We found that genetic diversity was resilient to moderate changes in ice cover, but a complete loss of connectivity resulted in rapid genetic erosion. Despite genetic erosion, populations persisted as long as nominal connectivity occurred between islands. Our work suggests that connectivity will decline, but martens would be resilient to moderate changes and, in the short term, the Apostle Islands can act as a refuge along this species' southern range boundary. Identifying thresholds in connectivity that maintain populations but allow for isolation from disturbance will be necessary to identify suitable areas for species conservation across space and time.

中文翻译：

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小而相连的岛屿可以在气候变化下维持人口和遗传多样性


为了应对环境变化的显着影响，保护战略通常包括确定能够有效维持脆弱物种的保护区。因此，确定维持受保护物种的人口和遗传活力的系统特定条件至关重要。连通性对于人口的持续存在起着至关重要的作用。岛屿一直是了解连通性和集合种群过程的模型系统，并已成为特别有利的保护目标。虽然岛屿可以免受大陆干扰，但尚不清楚需要何种程度的隔离才能避免不利的变化，同时又保持充分的联系以维持人口的生存能力。为了测试这个问题，我们通过比较冰桥连通性的历史和当代趋势以及模拟该系统内连通性减少的影响，探索了阿波斯尔群岛（苏必利尔湖内由 22 个岛屿组成的群岛）内的连通性。我们开发了一个基于人口统计的基于个体的模型，以明确测试连通性对影响美洲貂（Martes americana）持久性和遗传多样性的作用，美洲貂是一种森林食肉动物，在其南部范围边界处于危险之中。我们发现遗传多样性对冰盖的适度变化具有弹性，但连通性的完全丧失会导致遗传快速侵蚀。尽管存在遗传侵蚀，只要岛屿之间存在名义上的连通性，种群就会持续存在。我们的研究表明，连通性将会下降，但貂能够适应适度的变化，并且在短期内，阿波斯尔群岛可以作为该物种南部范围边界的避难所。 确定维持种群但允许隔离干扰的连通性阈值对于确定跨空间和时间物种保护的合适区域是必要的。