1. Biological invasions can greatly alter ecological communities, affecting not only the diversity and abundance but also composition of invaded assemblages. This is because invaders’ impacts are mediated by characteristics of resident species: some may be highly sensitive to invader impacts while others are unaffected or even facilitated. In some cases, this can result in invasive species promoting further invasions; in particular, herbivory by introduced animals has been shown to disproportionately harm native plants, which can indirectly benefit non‐native plants. Here, we investigated whether such patterns emerged through the effects of an invasive fish species on lake plant communities.
2. Specifically, we tested whether invasion of Minnesota (U.S.A.) lakes by Cyprinus carpio (common carp), an omnivorous, benthivorous fish known to reduce abundance and richness of aquatic plants, differentially affected native versus non‐native plant species. We applied statistical models to a large, long‐term monitoring dataset (206 macrophyte taxa recorded in 913 lakes over a 20‐year time period) to test whether carp altered community composition, to identify which macrophyte species were most sensitive to carp and determine whether species characteristics predicted carp sensitivity, and to characterise consequences of carp invasion on lake‐level vegetation attributes.
3. We found that carp exerted strong selective pressure on community composition. Native macrophytes, those with a more aquatic growth form, and those considered less tolerant of disturbance (i.e. higher coefficients of conservatism) were more sensitive to carp. Conversely, no introduced macrophytes exhibited sensitivity to carp and all had higher probabilities of occurrence as carp abundance increased. The net effect of carp invasion was a shift toward less species‐rich plant communities characterised by more non‐native and disturbance‐tolerant species.
4. These results have several implications for conservation and management. First, they reinforce the need to prevent further spread of carp outside of their native range. Where carp have already established, their control should be incorporated into efforts to restore aquatic vegetation; this may be an essential step for recovering particular plant species of high conservation importance. Furthermore, reducing carp abundance could have ancillary benefits of reducing dominance by invasive plant species. Lastly, where carp cannot be eliminated, managers should target native macrophytes that are relatively tolerant of carp in shoreline plantings and other revegetation efforts.

中文翻译：

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入侵鱼类在明尼苏达州的湖中促进入侵植物

1. 生物入侵可以极大地改变生态群落，不仅影响多样性和丰富度，还影响被入侵种群的组成。这是因为入侵者的影响是由常驻物种的特征所介导的：某些物种可能对入侵者的影响高度敏感，而另一些物种则不受影响甚至没有受到促进。在某些情况下，这可能导致入侵物种促进进一步入侵；特别是，已证明，引入动物的食草会对当地植物造成不成比例的损害，这可以间接使非本地植物受益。在这里，我们调查了这种模式是否通过入侵性鱼类对湖泊植物群落的影响而出现。
2. 具体而言，我们测试了鲤鱼（一种杂食性，杂食性鱼类，已知会降低水生植物的丰度和丰富度）对明尼苏达州（美国）湖泊的入侵是否对差异影响了本地植物物种和非本地植物物种的影响。我们将统计模型应用于大型的长期监测数据集（在20年的时间里在913个湖泊中记录了206个大型植物类群），以测试鲤鱼是否改变了群落组成，以确定哪种大型植物物种对鲤鱼最敏感，并确定是否物种特征预测了鲤鱼的敏感性，并表征了鲤鱼入侵对湖面植被属性的影响。
3. 我们发现鲤鱼对群落组成具有很强的选择性压力。天然大型植物，那些具有更多水生生长形式的大型植物，以及那些被认为容忍干扰较小（即，保守性系数较高）的植物，对鲤鱼更加敏感。相反，没有引入的大型植物对鲤鱼表现出敏感性，并且随着鲤鱼丰度的增加，它们都具有较高的发生概率。鲤鱼入侵的净效应是向物种较少的植物群落的转变，该群落以非本地和抗干扰物种较多为特征。
4. 这些结果对保护和管理有一些影响。首先，它们加强了防止鲤鱼在其本国范围以外进一步传播的需要。在已经建立鲤鱼的地方，应将其控制纳入恢复水生植被的工作中；这可能是恢复具有高度保护重要性的特定植物物种的重要步骤。此外，减少鲤鱼的丰度可能具有减少入侵植物引起的优势的辅助利益。最后，在无法消除鲤鱼的地方，管理者应针对在沿海种植和其他植被恢复活动中对鲤鱼具有相对耐受性的本地大型植物。