Data from: Population biology of establishment in New Zealand hedgehogs inferred from genetic and historical data: conflict or compromise?

The crucial steps in biological invasions, related to the shaping of genetic architecture and the current evolution of adaptations to a novel environment, usually occur in small populations during the phases of introduction and establishment. However, these processes are difficult to track in nature due to invasion lag, large geographic and temporal scales compared with human observation capabilities, the frequent depletion of genetic variance, admixture and other phenomena. In this study, we compared genetic and historical evidence related to the invasion of the West European hedgehog to New Zealand to infer details about the introduction and establishment. Historical information indicates that the species was initially established on the South Island. A molecular assay of populations from Great Britain and New Zealand using mitochondrial sequences and nuclear microsatellite loci was performed based on a set of analyses including approximate Bayesian computation, a powerful approach for disentangling complex population demographies. According to these analyses, the population of the North Island was most similar to that of the native area and showed greatest reduction in genetic variation caused by founder demography and/or drift. This evidence indicated the location of the establishment phase. The hypothesis was corroborated by data on climate and urbanization. We discuss the contrasting results obtained by the molecular and historical approaches in the light of their different explanatory power and the possible biases influencing the description of particular aspects of invasions, and we advocate the integration of the two types of approaches in invasion biology.

生物入侵过程中，与遗传架构塑造以及物种对新生境的适应性现代演化相关的关键步骤，通常发生在物种引入与定殖阶段的小型种群中。然而，受限于入侵滞后效应、远超人类观测能力的地理与时间尺度、频繁出现的遗传方差耗竭、遗传混杂及其他现象，这些过程在自然环境中难以被追踪。本研究针对西欧刺猬（West European hedgehog）入侵新西兰的相关遗传与历史证据展开比对分析，以推断其引入与定殖的具体细节。历史资料显示，该物种最初定殖于新西兰南岛。研究团队对英国与新西兰的刺猬种群开展分子检测，采用线粒体序列与核微卫星位点作为分子标记，并基于包括近似贝叶斯计算（approximate Bayesian computation）在内的一系列分析方法展开研究，该方法是解析复杂种群动态的高效手段。分析结果表明，新西兰北岛的种群与该物种的原生分布区种群亲缘关系最为接近，且其遗传变异因奠基者种群动态和/或遗传漂变发生了最大程度的缩减，该证据指向了该物种定殖阶段的发生区域。气候与城市化相关数据进一步佐证了这一假说。本研究结合两种研究方法的差异化解释能力，以及可能影响入侵过程特定方面描述的潜在偏倚，对分子与历史研究路径所得出的相悖结果展开讨论，并倡导在入侵生物学研究中整合这两类研究方法。