Abstract：
The ability of non-native species to successfully invade new ecosystems sometimes involves evolutionary processes such as hybridization. Hybridization can produce individuals with superior traits that give them a competitive advantage over their parent species, allowing for rapid spread. Here we assess growth, functional morphology, and species interactions between two non-native beachgrass species (Ammophila arenaria and A. breviligulata) and their recently discovered hybrid (A. arenaria × A. breviligulata) on the U.S. Pacific Northwest coast. We asked whether the hybrid beachgrass differs from its parent species in morphology and growth, whether it competes with its parent species, and, if so, what are the potential mechanisms of competition. Plant taxa were grown in low- and high-density monocultures and in two-way interactions in a common garden environment. We show that the hybrid grew taller and more densely, with greater total biomass, than either parent species. The hybrid was also the better competitor, resulting in the model prediction of competitive exclusion against A. breviligulata and, depending on its relative abundance, A. arenaria. The hybrid displays a mixed \'guerilla-phalanx\' growth form that allows it to spread laterally and achieve high shoot densities, giving it a competitive advantage. Given the current dominance of A. breviligulata compared to A. arenaria in most of the region where these taxa co-occur, we suggest that the hybrid will grow, compete, and spread quickly with potentially widespread consequences for the two non-native Ammophila congeners and the dunes they build.
摘要：
非本地物种成功入侵新生态系统的能力有时涉及进化过程，例如杂交。杂交可以产生具有优异性状的个体，使其具有相对于其亲本物种的竞争优势，允许快速传播。在这里，我们评估增长，功能形态学，以及两种非本地沙滩草物种（Ammophilaarenaria和A.breviligulata）与它们最近发现的杂种之间的物种相互作用（A.arenaria×A.breviligulata）在美国太平洋西北海岸。我们询问杂种海滩草在形态和生长上是否与其亲本物种不同，无论它是否与它的亲本物种竞争，and,如果是,潜在的竞争机制是什么。植物类群在低密度和高密度单种培养中生长，并在共同的花园环境中进行双向相互作用。我们表明，杂种长得更高，更密，总生物量更大，比任何一个亲本物种都多。混合动力车也是更好的竞争对手，从而实现了对A.breviligulata的竞争性排除模型预测，取决于它的相对丰度，A.竞技场。混合动力表现出混合的“游击-方骨”生长形式，使其能够横向传播并实现高的射击密度，给它一个竞争优势。鉴于在这些类群共同出现的大多数地区，与A.arenaria相比，A.breviligulata目前占主导地位，我们建议杂种会生长，竞争,并迅速传播，对两个非本地Ammophila同源物和他们建造的沙丘产生潜在的广泛影响。
