European earthworms were introduced to North America by European settlers about 400 years ago. Human-mediated introductions significantly contributed to the spread of European species, which commonly are used as fishing bait and are often disposed deliberately in the wild. We investigated the genetic structure of Lumbricus terrestris in a 100 km range south of Calgary, Canada, an area that likely was devoid of this species two decades ago. Genetic relationships among populations, gene flow, and migration events among populations were investigated using seven microsatellite markers and the mitochondrial 16S rDNA gene. Earthworms were collected at different distances from the city and included fishing baits from three different bait distributors. The results suggest that field populations in Alberta established rather recently and that bait and field individuals in the study area have a common origin. Genetic variance within populations decreased outside of the urban area, and the most distant populations likely originated from a single introduction event. The results emphasise the utility of molecular tools to understand the spatial extent and connectivity of populations of exotic species, in particular soil-delling species, that invade native ecosystems and to obtain information on the origin of populations. Such information is crucial for developing management and prevention strategies to limit and control establishment of non-native earthworms in North America.

中文翻译：

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北美城乡梯度的入侵蚯蚓（Lumbricus terrestris，Lumbricidae）遗传结构的变化

大约 400 年前，欧洲定居者将欧洲蚯蚓引入北美。人类介导的引入极大地促进了欧洲物种的传播，这些物种通常被用作鱼饵，并且经常被故意丢弃在野外。我们在加拿大卡尔加里以南 100 公里范围内调查了陆生蚯蚓的遗传结构，该地区在 20 年前可能没有该物种。使用七个微卫星标记和线粒体 16S rDNA 基因研究了种群之间的遗传关系、基因流动和种群之间的迁移事件。蚯蚓是在距城市不同距离的地方收集的，包括来自三个不同诱饵经销商的鱼饵。结果表明，艾伯塔省的野外种群是最近才建立的，并且研​​究区域中的诱饵和野外个体具有共同的起源。人口内的遗传变异在市区以外减少，最远的人口可能起源于单一的引入事件。结果强调了分子工具的效用，以了解外来物种种群的空间范围和连通性，特别是土壤退化物种，这些物种入侵本地生态系统并获取有关种群起源的信息。这些信息对于制定管理和预防策略以限制和控制北美非本地蚯蚓的建立至关重要。最遥远的种群可能来自单一的引入事件。结果强调了分子工具的效用，以了解外来物种种群的空间范围和连通性，特别是土壤退化物种，这些物种入侵本地生态系统并获取有关种群起源的信息。这些信息对于制定管理和预防策略以限制和控制北美非本地蚯蚓的建立至关重要。最遥远的种群可能来自单一的引入事件。结果强调了分子工具的效用，以了解外来物种种群的空间范围和连通性，特别是土壤退化物种，这些物种入侵本地生态系统并获取有关种群起源的信息。这些信息对于制定管理和预防策略以限制和控制北美非本地蚯蚓的建立至关重要。