Data from: Widespread primary, but geographically restricted secondary, human introductions of wall lizards, Podarcis muralis

Establishing the introduction pathways of alien species is a fundamental task in invasion biology. The common wall lizard, Podarcis muralis, has been widely introduced outside of its native range in both Europe and North America, primarily through escaped pets or deliberate release of animals from captive or wild populations. Here we use Bayesian clustering, approximate Bayesian computation (ABC) methods and network analyses to reconstruct the origin and colonization history of 23 non-native populations of wall lizards in England. Our analyses show that established populations in southern England originate from at least nine separate sources of animals from native populations in France and Italy. Secondary introductions from previously established non-native populations were supported for eleven (47%) populations. In contrast to the primary introductions, secondary introductions were highly restricted geographically and appear to have occurred within a limited time frame rather than being increasingly common. Together, these data suggest that extant wall lizard populations in England are the result of isolated accidental and deliberate releases of imported animals since the 1970s, with only local translocation of animals from established non-native populations. Given that populations introduced as recently as 25 years ago show evidence of having adapted to cool climate, discouraging further translocations may be important to prevent more extensive establishment on the south coast of England.

厘清外来物种的入侵路径是入侵生物学的核心研究任务之一。普通壁蜥（Podarcis muralis）已在欧洲与北美原生分布范围之外广泛建立引入种群，其引入途径主要为宠物逃逸以及人工释放圈养或野生捕获的个体。本研究采用贝叶斯聚类、近似贝叶斯计算（ABC）以及网络分析方法，重构了英格兰境内23个外来壁蜥种群的起源与定殖历史。分析结果显示，英格兰南部的定殖种群至少源自法国与意大利境内的9个独立原生种群来源。研究证实，11个（占比47%）种群的形成源自先前已建立的外来种群的二次引入。与初次引入不同，二次引入在地理分布上高度受限，且似乎仅发生在一段有限的时间窗口内，并未随时间推移愈发频繁。综合来看，这些数据表明，英格兰现存的壁蜥种群均源自20世纪70年代以来零星发生的进口个体意外逃逸与人工放生事件，且仅存在来自已建立外来种群的局地个体转移。鉴于仅引入25年的种群已显现出适应凉爽气候的特征，因此限制进一步的个体转移，或对防止英格兰南海岸出现更广泛的种群定殖具有重要意义。