Data from: A genetic assessment of the human-facilitated colonization history of black swans in Australia and New Zealand

Movement of species beyond their indigenous distribution can fundamentally alter the conservation status of the populations involved. If introductions are human-facilitated, introduced species could be considered pests. Characterizing the colonization history of introduced species can, therefore, be critical to formulating the objectives and nature of wildlife management strategies. The black swan (Cygnus atratus) is native to Australia but is considered a reintroduced species in New Zealand, where the endemic population was reported extinct during the 19th century. After the re-introduction of a small number of individuals from Australia, the New Zealand population expanded unexpectedly rapidly, which was attributed to simultaneous waves of migration from Australia. An alternative, but hitherto unformalized, hypothesis is that local extant populations remained and admixed with introduced individuals. To contribute to our understanding of the reintroduction history of the species, we investigated dispersal patterns and demographic histories of seven populations from Australia and New Zealand, using population genetic inferences from a microsatellite dataset. Our results on genetic structure, dispersal rates, and demographic histories provide mixed evidences on the origin of New Zealand black swans. The hypothesis that reintroduced individuals mixed with remaining local individuals and that the subsequent dramatic population expansion may have been due to genetic rescue of the inbred indigenous population cannot be discarded and needs further investigation.

物种跨越原生分布范围的迁移，可从根本上改变相关种群的保护现状。若物种引入由人类活动促成，则该引入物种可被认定为有害生物。因此，厘清引入物种的定殖历史，对制定野生动物管理策略的目标与核心逻辑至关重要。黑天鹅（Cygnus atratus）原生分布于澳大利亚，但在新西兰被视为重新引入物种——19世纪有记录显示新西兰的特有黑天鹅种群已宣告灭绝。在从澳大利亚引入少量个体后，新西兰黑天鹅种群出现了出乎意料的快速扩张，该现象曾被归因于来自澳大利亚的多波次同步迁入。另有一个迄今尚未被正式系统化阐释的假说认为：当地现存种群并未灭绝，而是与引入个体发生了基因混合。为加深对该物种重新引入历史的认知，本研究利用微卫星（microsatellite）数据集开展种群遗传学推断，对来自澳大利亚与新西兰的7个黑天鹅种群的扩散模式及种群历史动态展开了研究。本研究关于种群遗传结构、扩散速率及种群历史动态的结果，针对新西兰黑天鹅的起源问题提供了互为矛盾的证据。“引入个体与当地残存种群发生基因混合，且后续种群的急剧扩张或源于近交原生种群的遗传拯救”这一假说无法被排除，仍需开展进一步研究。