BACKGROUND In most regions of the world human influences on the distribution of flora and fauna predate complete biotic surveys. In some cases this challenges our ability to discriminate native from introduced species. This distinction is particularly critical for isolated populations, because relicts of native species may need to be conserved, whereas introduced species may require immediate eradication. Recently an isolated population of seal salamanders, Desmognathus monticola, was discovered on the Ozark Plateau, approximately 700 km west of its broad continuous distribution in the Appalachian Mountains of eastern North America. Using Nested Clade Analysis (NCA) we test whether the Ozark isolate results from population fragmentation (a natural relict) or long distance dispersal (a human-mediated introduction). RESULTS Despite its broad distribution in the Appalachian Mountains, the primary haplotype diversity of D. monticola is restricted to less than 2.5% of the distribution in the extreme southern Appalachians, where genetic diversity is high for other co-distributed species. By intensively sampling this genetically diverse region we located haplotypes identical to the Ozark isolate. Nested Clade Analysis supports the hypothesis that the Ozark population was introduced, but it was necessary to include haplotypes that are less than or equal to 0.733% divergent from the Ozark population in order to arrive at this conclusion. These critical haplotypes only occur in < 1.2% of the native distribution and NCA excluding them suggest that the Ozark population is a natural relict. CONCLUSION Our analyses suggest that the isolated population of D. monticola from the Ozarks is not native to the region and may need to be extirpated rather than conserved, particularly because of its potential negative impacts on endemic Ozark stream salamander communities. Diagnosing a species as introduced may require locating nearly identical haplotypes in the known native distribution, which may be a major undertaking. Our study demonstrates the importance of considering comparative phylogeographic information for locating critical haplotypes when distinguishing native from introduced species.

中文翻译：

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比较系统发育地理学在诊断引进物种中的重要性：来自海豹蝾螈Desmognathus monticola的教训。


背景技术在世界大多数地区，人类对动植物分布的影响早于完整的生物调查。在某些情况下，这挑战了我们区分本地物种和外来物种的能力。这种区别对于孤立的种群尤其重要，因为本地物种的遗迹可能需要保护，而引进的物种可能需要立即根除。最近，在奥扎克高原上发现了一个孤立的海豹蝾螈种群——Desmognathus monticola，该高原位于北美东部阿巴拉契亚山脉广泛连续分布的以西约 700 公里处。使用嵌套进化枝分析 (NCA)，我们测试了奥扎克分离株是否是由于种群破碎（自然遗迹）或长距离扩散（人类介导的引入）造成的。结果 尽管在阿巴拉契亚山脉广泛分布，但 D. monticola 的主要单倍型多样性仅限于阿巴拉契亚最南端分布的不到 2.5%，而该地区其他共同分布物种的遗传多样性很高。通过对这个遗传多样性区域进行集中采样，我们找到了与奥扎克分离株相同的单倍型。嵌套进化枝分析支持奥索卡群体被引入的假设，但需要包括与奥扎克群体差异小于或等于 0.733% 的单倍型才能得出这一结论。这些关键单倍型仅出现在本地分布的 < 1.2% 中，NCA 排除它们表明奥扎克种群是自然遗迹。结论 我们的分析表明 D. 的孤立群体。 来自奥沙克的蒙蒂科拉并不是该地区的本地物种，可能需要灭绝而不是保护，特别是因为它对特有的奥沙克溪蝾螈群落有潜在的负面影响。诊断引入的物种可能需要在已知的本地分布中定位几乎相同的单倍型，这可能是一项艰巨的任务。我们的研究证明了在区分本地物种和引进物种时考虑比较系统发育地理学信息以定位关键单倍型的重要性。