Plants have evolved resource-conservative and resource-acquisitive strategies to deal with variability in rainfall, but interactions with dominant invasive species may undermine these adaptations. To investigate the relative effect of invaders on species with these two strategies, we manipulated rainfall and invasive grass presence and measured demographic rates in three resource-acquisitive and three resource-conservative native annual forbs. We found that invasive grasses were harmful to all of the target species, but especially the resource-acquisitive ones, and that these effects were stronger under experimental drought. Invasive grass presence under drought lowered per capita population growth rates of acquisitive natives through increased mortality and decreased seed set. While invasive grasses also decreased per capita growth rates of resource-conservative natives, they did so by increasing mortality under experimental watering and by limiting the production of seed under experimental drought. Invasive species can thus interact with climatic fluctuations to make bad years worse for resource-acquisitive natives and good years less good for resource-conservative natives, and they may generally tend to undermine the acquisitive strategy more than the conservative one.

中文翻译：

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入侵物种与气候变化相互作用以减少本地人的成功

植物已经进化出资源节约和资源获取策略来应对降雨量的变化，但与主要入侵物种的相互作用可能会破坏这些适应性。为了使用这两种策略研究入侵者对物种的相对影响，我们操纵了降雨和入侵草的存在，并测量了三种资源获取型和三种资源保守型本地一年生杂草的人口统计率。我们发现入侵草对所有目标物种都是有害的，尤其是对资源获取的物种，并且这些影响在实验性干旱下更强。干旱下的入侵草的存在通过增加死亡率和减少种子结实降低了贪婪的本地人的人均人口增长率。虽然侵入性草也降低了资源保守型本地人的人均增长率，但它们是通过在实验性浇水下增加死亡率和在实验性干旱下限制种子产量来实现的。因此，入侵物种可以与气候波动相互作用，使资源获取型本地人的坏年变得更糟，而资源保守型本地人的好年头则不那么好，并且它们通常比保守策略更倾向于破坏获取策略。