Data from: Gene flow and effective population sizes of the butterfly Maculinea alcon in a highly fragmented, anthropogenic landscape

Understanding connectivity among populations in fragmented landscapes is of paramount importance in species conservation because it determines their long-term viability and helps to identify and prioritize populations to conserve. Rare and sedentary species are particularly vulnerable to habitat fragmentation as they occupy narrow niches or restricted habitat ranges. Here, we assess contemporary interpopulation connectedness of the threatened, myrmecophilous butterfly, Maculinea alcon, in a highly fragmented landscape. We inferred dispersal, effective population sizes, genetic diversity and structure based on 14 locations of M. alcon in Belgium and the Netherlands using data from 12 microsatellite loci. Despite the reported sedentary behaviour of M. alcon, we observed moderate levels of contemporary dispersal between patches, but only in landscapes where populations were located within a distance of 3 km from neighbouring populations. Estimates of effective population sizes (Ne) were very low (ranging from 1.6 to 17.6) and bottleneck events occurred in most of the studied populations. We discuss the functional conservation units delineated based on a former mark-release-recapture study, and formulate appropriate conservation strategies to maintain viable (meta)populations in highly fragmented, anthropogenic landscapes.解析破碎化景观中种群间的连通性，对于物种保护具有至关重要的意义，因其直接决定物种的长期存续能力，还可辅助识别需保护的种群并确定其保护优先级。稀有且具定居习性的物种因生态位狭窄或栖息地范围受限，尤其易受到栖息地破碎化的威胁。本研究以受威胁的嗜蚁蝴蝶阿尔康蓝灰蝶（Maculinea alcon）为研究对象，在高度破碎化的景观中评估其当代种群连通性。我们基于比利时与荷兰境内14个阿尔康蓝灰蝶种群的12个微卫星位点（microsatellite loci）数据，推断了该蝶的扩散能力、有效种群大小（effective population sizes, Ne）、遗传多样性及种群遗传结构。尽管已有研究证实阿尔康蓝灰蝶具有定居习性，但我们观察到种群所在的生境斑块间存在中等程度的当代扩散，且此类扩散仅发生在相邻种群间距不超过3公里的景观中。有效种群大小的估计值极低（范围为1.6至17.6），且多数研究种群均经历过遗传瓶颈事件。我们讨论了基于既往标记-释放-重捕研究划定的功能性保护单元，并针对高度破碎化的人为活动影响景观，提出了维持可行集合种群（metapopulation）的适宜保护策略。