Abstract Aims Two key hypotheses in invasion biology are that certain traits underlie invasiveness in introduced species and that these traits are selected for during or after introduction. We tested these hypotheses by focusing on two traits likely to confer invasiveness, high increase in growth in response to increase in nutrients and low decrease in growth in response to competition. Methods We compared four species of Carpobrotus that differ in invasiveness, using species from four continents: Africa, Australia, Europe, and North America. To test for selection for these traits in C. edulis, a highly invasive species, we compared plants from its native range in South Africa to plants from the other three regions, where C. edulis has been introduced. Plants were propagated in a common garden. Offspring were then grown alone with or without added nutrients, and together with another species of Carpobrotus or with the grass Ammophila arenaria (a co-occurring native species in Europe) without added nutrients. Important Findings Response to nutrients did not differ between species of Carpobrotus, nor was competitive response less negative in more invasive species. However, increase in growth in response to added nutrients was greater in introduced than in native C. edulis. Moreover, fresh mass per ramet at the start of treatments was higher in the two invasive species than in the two non-invasive ones. We provide new evidence that introduction can select for response to nutrient enrichment in invasive species and add to the evidence for an association between size and invasiveness in introduced plants.

中文翻译：

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四大洲鲢鱼入侵生态的比较：对营养物质和竞争的反应

摘要目的入侵生物学中的两个关键假设是某些特征是引入物种的入侵性的基础，并且这些特征是在引入期间或之后选择的。我们通过关注可能赋予侵入性的两个特征来测试这些假设，即响应于营养增加的高增长和响应于竞争的低增长。方法 我们使用来自四大洲的物种：非洲、澳大利亚、欧洲和北美，比较了入侵性不同的四种 Carpobrotus。为了测试在高入侵物种 C. edulis 中对这些性状的选择，我们将其在南非本土的植物与其他三个地区的植物进行了比较，其中 C. edulis 已被引入。植物在一个共同的花园中繁殖。然后在添加或不添加营养的情况下单独培育后代，并与另一种 Carpobrotus 或草 Ammophila arearia（欧洲同时存在的本地物种）一起生长，而不添加营养。重要发现 Carpobrotus 物种之间对营养物质的反应没有差异，更具入侵性的物种的竞争反应也没有那么负面。然而，响应添加的营养物质的生长增加在引入的比在天然的 C. edulis 中更大。此外，两种入侵物种在处理开始时每分株的新鲜质量高于两种非入侵物种。