Moyano Jaime, Chiuffo Mariana C, Nuñez Martín A, Rodriguez-Cabal Mariano A
Grupo de Ecología de Invasiones, INIBIOMA, Universidad Nacional del Comahue, CONICET, Avenida de los Pioneros 2350, San Carlos de Bariloche, Río Negro, Argentina.
Oecologia. 2019 Apr;189(4):981-991. doi: 10.1007/s00442-019-04354-8. Epub 2019 Mar 13.
Why some non-native plant species invade, and others fail remains an elusive question. Plant invasion success has been associated with specific species traits. Yet, we have limited knowledge of the mechanisms relating these traits to invasion potential. General patterns of biotic resistance by seed predation may provide a mechanism that helps separate invasive from non-invasive plants. Seed predation is an important barrier against plant establishment for many plant species. It may, therefore, create a selective filter against non-native plant establishment based on plant traits related to seed predation rate. In two cafeteria-style seed predation experiments in a steppe ecosystem in Patagonia (Argentina) we provided seeds of 16 non-native Pinaceae covering a 300-fold variation in seed mass, a 200-fold variation in seed volume and 75-fold variation in seed toughness. Seed removal decreased with seed mass and seed volume. Seed toughness was not a significant predictor while seed volume was the best predictor of predators' preference. However, for species of this family small seed size is the most important predictor of species invasiveness. Our results show that seed predation does not explain Pinaceae invasive success. In our system, species that have smaller seeds (i.e., more invasive) are preferentially consumed by seed predators. Seed mass was not the best predictor of granivory rates, despite being the seed trait on which most studies have been focused. Our ability to predict future invasion and understand invasion success could benefit from other studies that focus on the mechanisms behind invasive traits.
为何一些非本地植物物种能够成功入侵，而另一些却失败了，这仍然是一个难以捉摸的问题。植物入侵的成功与特定的物种特性相关。然而，我们对于将这些特性与入侵潜力联系起来的机制了解有限。种子捕食导致的生物抗性的一般模式可能提供了一种有助于区分入侵植物和非入侵植物的机制。对于许多植物物种而言，种子捕食是阻止植物定居的重要障碍。因此，它可能基于与种子捕食率相关的植物特性，对非本地植物的定居形成一种选择性筛选。在巴塔哥尼亚（阿根廷）一个草原生态系统中进行的两项自助式种子捕食实验里，我们提供了16种非本地松科植物的种子，这些种子在种子质量上有300倍的差异，种子体积有200倍的差异，种子韧性有75倍的差异。种子被移除的比例随种子质量和种子体积的增加而降低。种子韧性不是一个显著的预测指标，而种子体积是捕食者偏好的最佳预测指标。然而，对于这个科的物种来说，小种子大小是物种入侵性的最重要预测指标。我们的结果表明，种子捕食并不能解释松科植物的入侵成功。在我们的系统中，种子较小（即更具入侵性）的物种更容易被种子捕食者消耗。尽管种子质量是大多数研究关注的种子特性，但它并不是种子被食率的最佳预测指标。我们预测未来入侵和理解入侵成功的能力可能会受益于其他关注入侵特性背后机制的研究。
