Park Keon Young, Lucas Mel, Chaulk Andrew, Matter Stephen F, Roland Jens, Keyghobadi Nusha
Department of Biology, Western University, London, Ontario N6A 5B7, Canada.
Department of Biology, Memorial University of Newfoundland, St John's, Newfoundland A1C 5S7, Canada.
R Soc Open Sci. 2024 Jul 31;11(7):240557. doi: 10.1098/rsos.240557. eCollection 2024 Jul.
Widespread fragmentation and degradation of habitats make organisms increasingly vulnerable to declines in population size. Immigration is a key process potentially affecting the rescue and persistence of populations in the face of such pressures. Field research addressing severe demographic declines in the context of immigration among interconnected local populations is limited owing to difficulties in detecting such demographic events and the need for long-term monitoring of populations. In a 17-subpopulation metapopulation of the butterfly, , all adults observed in two adjacent patches were removed over eight consecutive generations. Despite this severe and long-term reduction in survival and reproduction, the targeted populations did not go extinct. Here, we use genetic data to assess the role of immigration versus reproduction in allowing the persistence of these populations. We genotyped 471 samples collected from the targeted populations throughout the removal experiment at 152 single nucleotide polymorphisms. We found no reduction in the genetic diversity of the targeted populations over time, but a decrease in the number of loci in Hardy-Weinberg equilibrium, consistent with a high level of immigration from multiple surrounding populations. Our results highlight the role of connectivity and movement in making metapopulations resilient to even severe and protracted localized population reductions.
栖息地的广泛破碎化和退化使生物越来越容易受到种群数量下降的影响。在面对此类压力时，迁入是一个可能影响种群救援和存续的关键过程。由于难以检测到此类种群动态事件以及需要对种群进行长期监测，针对相互关联的当地种群之间迁入背景下严重种群数量下降的实地研究有限。在一个由17个亚种群组成的蝴蝶集合种群中，连续八代移除了在两个相邻斑块中观察到的所有成年个体。尽管生存和繁殖出现了这种严重且长期的减少，但目标种群并未灭绝。在这里，我们使用遗传数据来评估迁入与繁殖在使这些种群得以存续方面所起的作用。在整个移除实验过程中，我们对从目标种群收集的471个样本在152个单核苷酸多态性位点进行了基因分型。我们发现目标种群的遗传多样性并未随时间减少，但处于哈迪 - 温伯格平衡的位点数量有所下降，这与来自多个周边种群的高水平迁入相一致。我们的结果凸显了连通性和迁移在使集合种群能够抵御甚至严重且持久的局部种群减少方面所起的作用。
