Hybridisation increases invasive knotweed success

Hybridization is one of the fundamental mechanisms by which rapid evolution can occur in exotic species. If hybrids show increased vigour, this could significantly contribute to invasion success. Here, we compared the success of the two invasive knotweeds, Fallopia japonica and F. sachalinensis, and their hybrid, F. × bohemica, in competing against experimental communities of native plants. Using plant material from multiple clones of each taxon collected across a latitudinal gradient in Central Europe, we found that knotweed hybrids performed significantly better in competition with a native community, and that they more strongly reduced the growth of the native plants. One of the parental species, F. sachalinensis, regenerated significantly less well from rhizomes, and this difference disappeared if activated carbon was added to the substrate, which suggests allelopathic inhibition of F. sachalinensis regeneration by native plants. We found substantial within-taxon variation in compet...杂交是外来物种快速演化的核心机制之一。若杂交个体表现出更强的活力，则可显著提升其入侵成功率。本研究对比了两种入侵虎杖——日本虎杖（Fallopia japonica）、萨哈林虎杖（Fallopia sachalinensis）及其杂交种波西米亚虎杖（F. × bohemica）与本土植物实验群落的竞争能力。我们使用采自中欧纬度梯度下各分类群的多个克隆株系作为实验材料，结果发现：虎杖杂交种在与本土群落的竞争中表现显著更优，且对本土植物生长的抑制作用更强。其中一个亲本物种萨哈林虎杖的根状茎再生能力显著更弱；若向培养基质中添加活性炭，该差异便会消失，这表明本土植物通过化感作用抑制了萨哈林虎杖的再生。本研究发现各分类群内部存在显著的竞争相关变异……