The illegal pet trade facilitates the global dispersal of invasive alien species (IAS), providing opportunities for new pests to establish in novel recipient environments. Despite the increasing threat of IAS to the environment and economy, biosecurity efforts often lack suitable, scientifically-based methods to make effective management decisions, such as identifying an established IAS population from a single incursion event. We present a proof-of-concept for a new application of a stable isotope technique to identify wild and captive histories of an invasive pet species. Twelve red-eared slider turtles (Trachemys scripta elegans) from historic Australian incursions with putative wild, captive and unknown origins were analysed to: (1) present best-practice methods for stable isotope sampling of T. s. elegans incursions; (2) effectively discriminate between wild and captive groups using stable isotope ratios; and (3) present a framework to expand the methodology for use on other IAS species. A sampling method was developed to obtain carbon (δ13C) and nitrogen (δ15N) stable isotope ratios from the keratin layer of the carapace (shells), which are predominantly influenced by dietary material and trophic level respectively. Both δ13C and δ15N exhibited the potential to distinguish between the wild and captive origins of the samples. Power simulations demonstrated that isotope ratios were consistent across the carapace and a minimum of eight individuals were required to effectively discriminate wild and captive groups, reducing overall sampling costs. Statistical classification effectively separated captive and wild groups by δ15N (captive: δ15N‰ ≥ 9.7‰, minimum of 96% accuracy). This study outlines a practical and accessible method for detecting IAS incursions, to potentially provide biosecurity staff and decision-makers with the tools to quickly identify and manage future IAS incursions.

中文翻译：

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宠物还是害虫？确定外来入侵物种来源的稳定同位素方法

非法的宠物贸易促进了外来入侵物种（IAS）的全球扩散，为新的有害生物在新的接收者环境中定殖提供了机会。尽管国际会计准则对环境和经济的威胁越来越大，但生物安全工作通常缺乏合适的，基于科学的方法来做出有效的管理决策，例如从一次入侵事件中确定已建立的国际会计准则人口。我们提出了一种新的概念证明，用于稳定同位素技术的新应用，以确定入侵性宠物物种的野生和圈养历史。分析了十二个来自澳大利亚历史性入侵的野生，圈养和未知来源的红耳滑龟（Trachemys scripta elegans），它们被分析为：（1）提出了对T. s进行稳定同位素采样的最佳实践方法。线虫入侵；（2）使用稳定的同位素比率有效地区分野生和圈养群体；（3）提出了一个框架，以扩展在其他IAS物种上使用的方法。开发了一种采样方法，以从甲壳（壳）的角蛋白层获得碳（δ13C）和氮（δ15N）稳定同位素比，这分别受饮食材料和营养水平的影响。δ13​​C和δ15N均具有区分样品野生和捕获来源的潜力。功率模拟表明，整个甲壳中的同位素比率是一致的，并且至少需要八个人才能有效地区分野生和圈养群体，从而降低了总体采样成本。统计分类通过δ15N有效地分离了圈养和野生群体（圈养：δ15N‰≥9.7‰，最低96％的准确度）。这项研究概述了一种检测IAS入侵的实用且可访问的方法，可以为生物安全人员和决策者提供快速识别和管理未来IAS入侵的工具。