Competition is commonly thought to underlie the impact of plant invasions. However, competitive effects of aliens and competitive response of natives may also change over time. Indeed, as with time, the novelty of an invader decreases, the accumulated eco-evolutionary experience of resident species may eventually limit invasion success. We aimed to gain insights on whether directional changes in biotic interactions over time or more general differences between natives and aliens, for instance, resulting from an introduction bias, are relevant in determining competitive ability. We conducted a pairwise competition experiment in a target-neighbour design, using 47 Asteraceae species with residence times between 8 years-12,000 years in Germany. We first tested whether there are differences in performance in intraspecific competition amongst invasion status groups, that is casual and established neophytes, archaeophytes or native species. We then evaluated whether competitive response and effects depend on residence time or invasion status. Lastly, we assessed whether competitive effects influence range sizes. We found only limited evidence that native target species tolerate neighbours with longer potential co-existence times better, whereas differences in competitive ability were mostly better explained by invasion status than residence time. Although casual neophytes produced most biomass in intraspecific competition, they had the weakest per-capita competitive effects on natives. Notably, we did not find differences between established neophytes and natives, both of which ranked highest in interspecific competitive ability. This lack of differences might be explained by a biased selection of highly invasive or rare native species in previous studies or because invasion success may result from mechanisms other than interspecific competitive superiority. Accordingly, interspecific per-capita competitive effects did not influence range sizes. Further studies across a broader range of environmental conditions, involving other biotic interactions that indirectly influence plant-plant interactions, may clarify when eco-evolutionary adaptations to new invaders are a relevant mechanism.

中文翻译：

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本土和外来植物的竞争能力：停留时间和入侵状态的影响

通常认为竞争是植物入侵的基础。但是，外星人的竞争影响和本地人的竞争反应也可能随时间变化。实际上，随着时间的推移，入侵者的新颖性会下降，居民物种积累的生态进化经验最终可能会限制入侵的成功。我们旨在获取有关生物相互作用的方向变化（随时间变化）或本地人与外星人之间更普遍的差异（例如，由于引进偏好而导致的差异）是否与确定竞争能力相关的见解。我们在目标邻域设计中进行了成对竞争实验，使用了47个菊科物种，它们在德国的居住时间在8年至12,000年之间。我们首先测试了入侵状态组之间的种内竞争表现是否存在差异，这些状态是偶然的和已建立的新植物，古植物或本地物种。然后，我们评估了竞争反应和效果是否取决于停留时间或入侵状态。最后，我们评估了竞争效应是否会影响范围大小。我们仅发现了有限的证据，即本土目标物种对邻居的耐受性更好，而其潜在的共存时间更长，而竞争能力的差异大多可以通过入侵状态比停留时间来更好地解释。尽管休闲新手在种内竞争中产生了最多的生物量，但它们对本地人的人均竞争作用最弱。值得注意的是，我们没有发现成熟的新手和本地人之间的差异，两者的种间竞争能力均排名最高。这种差异的缺乏可能是由于先前研究中偏爱高入侵性或稀有本地物种的选择造成的，或者入侵成功可能是由于种间竞争优势以外的其他机制导致的。因此，种间人均竞争效应不会影响范围大小。在更广泛的环境条件下进行的进一步研究，包括间接影响植物与植物相互作用的其他生物相互作用，可能会澄清何时对新入侵者进行生态进化适应是一种相关机制。这种差异的缺乏可能是由于先前研究中偏爱高入侵性或稀有本地物种的选择造成的，或者入侵成功可能是由于种间竞争优势以外的其他机制导致的。因此，种间人均竞争效应不会影响范围大小。在更广泛的环境条件下进行的进一步研究，包括间接影响植物与植物相互作用的其他生物相互作用，可能会澄清何时对新入侵者进行生态进化适应是一种相关机制。这种差异的缺乏可能是由于先前研究中偏爱高入侵性或稀有本地物种的选择造成的，或者入侵成功可能是由于种间竞争优势以外的其他机制导致的。因此，种间人均竞争效应不会影响范围大小。在更广泛的环境条件下进行的进一步研究，包括间接影响植物与植物相互作用的其他生物相互作用，可能会澄清何时对新入侵者进行生态进化适应是一种相关机制。