The great plasticity and diverse reproductive strategies of invasive alien plants are widely assumed to contribute to invasion success, even in extreme areas, often displacing native species. In this context, climate change creates new opportunities for biological invasions. Environmental variability and global warming are two of the climatic processes that may promote invasiveness, since alien species modulate their phenology to succeed under these circumstances. We monitored the phenological development (phenological stage advancement) of the two main invasive alien species: Poa annua L. and Cerastium fontanum Baumg. in the sub‐Antarctic Macquarie Island during the austral summer period along an altitudinal gradient. We found that higher temperatures lead to increased plant height and accelerated phenological development than lower temperatures in P. annua but found no direct evidence of the latter in C. fontanum. However, increased temperature variability negatively affected the phenological development of both species. Interestingly, despite their different reproductive strategy (rapid and impromptu in P. annua, and more synchronic and gradual in C. fontanum), both species prolifically succeeded in producing seeds at all sites showing the great acclimation of these two alien species even in limiting conditions. Since both alien species in Macquarie Island showed larger size and faster phenology at lower altitudes (i.e. milder conditions), this would indicate a great influence of ameliorating abiotic extremes on alien plant invasive capabilities at environmental extremes. Thus, our results warn of the increasing capabilities under climatic warming scenarios for alien plants to reproduce even at such remote ranges. This highlights the need to reinforce calls for special attention to prevent the spread of these kinds of species to other similar sub‐polar areas, where intensive post‐introduction management may be difficult or expensive.

中文翻译：

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变暖和温度变化较小有利于南极麦格理岛上两种入侵杂草的加速植物物候学

外来入侵植物的巨大可塑性和多样化的繁殖策略被广泛认为有助于入侵成功，即使在极端地区，通常会取代本地物种。在这种情况下，气候变化为生物入侵创造了新的机会。环境变化和全球变暖是可能促进入侵的两个气候过程，因为外来物种调节其物候以在这种情况下获得成功。我们监测了两种主要入侵外来物种：Poa annua L.和Cerastium fontanum的物候发展（物候阶段进展）鲍姆 在南极夏季的南极麦格理岛沿高度梯度。我们发现，较高的温度导致增加的植物高度，加快物候的发展比在较低温度下P.青蒿却发现后者的直接证据C. fontanum。但是，温度变异性的增加对这两个物种的物候发展均产生负面影响。有趣的是，尽管它们的繁殖策略不同（在P. annua中迅速而即兴，而在C. fontanum中则更为共时和渐进。），这两个物种都在所有地点成功繁殖了种子，即使在有限的条件下，也显示出这两个外来物种的高度适应。由于麦格理岛上的两种外来物种在较低的高度（即较温和的条件）下均表现出较大的大小和更快的物候学特征，因此这表明改善非生物极端性对极端环境中外来植物的入侵能力具有很大影响。因此，我们的结果警告了在气候变暖情况下外来植物即使在如此遥远的范围内繁殖的能力也不断增强。这凸显了需要加强呼吁的特别注意，以防止这类物种扩散到其他类似的亚极地区，在这些地区，加强引进后的管理可能是困难或昂贵的。