Funk Jennifer L, Vitousek Peter M
Department of Biological Sciences, Stanford University, Stanford, California 94305-5020, USA.
Nature. 2007 Apr 26;446(7139):1079-81. doi: 10.1038/nature05719.
No species can maximize growth, reproduction and competitive ability across all environments, so the success of invasive species is habitat-dependent. Nutrient-rich habitats often experience more invasion than resource-poor habitats, a pattern consistent with traits generally associated with successful invaders (high growth rates, early reproduction and many offspring). However, invaders do colonize resource-poor environments, and the mechanisms that allow their success in these systems are poorly understood. Traits associated with resource conservation are widespread among species adapted to resource-poor environments, and invasive species may succeed in low-resource environments by employing resource conservation traits such as high resource-use efficiency (RUE; carbon assimilation per unit of resource). We investigated RUE in invasive and native species from three habitats in Hawaii where light, water or nutrient availability was limiting to plant growth. Here we show that across multiple growth forms and broad taxonomic diversity invasive species were generally more efficient than native species at using limiting resources on short timescales and were similarly efficient when RUE measures were integrated over leaf lifespans. Our data challenge the idea that native species generally outperform invasive species under conditions of low resource availability, and suggest that managing resource levels is not always an effective strategy for invasive species control.
没有哪个物种能在所有环境中都实现生长、繁殖和竞争能力的最大化，因此入侵物种的成功与否取决于栖息地。营养丰富的栖息地通常比资源匮乏的栖息地遭受更多的入侵，这种模式与通常与成功入侵者相关的特征（高生长率、早期繁殖和众多后代）一致。然而，入侵者确实会在资源匮乏的环境中定殖，而它们在这些系统中取得成功的机制却鲜为人知。与资源保护相关的特征在适应资源匮乏环境的物种中广泛存在，入侵物种可能通过采用资源保护特征，如高资源利用效率（RUE；单位资源的碳同化量），在低资源环境中取得成功。我们研究了来自夏威夷三个栖息地的入侵物种和本地物种的资源利用效率，在这些栖息地中，光照、水分或养分的可利用性限制了植物生长。我们在此表明，在多种生长形式和广泛的分类多样性中，入侵物种在短时间尺度上利用有限资源通常比本地物种更有效，并且当在叶片寿命期间综合资源利用效率测量值时，它们同样有效。我们的数据挑战了在低资源可利用条件下本地物种通常优于入侵物种的观点，并表明管理资源水平并不总是控制入侵物种的有效策略。
