Data from: Woody climbers show greater population genetic differentiation than trees: insights into the link between ecological traits and diversification

The climbing habit is a key innovation in plants: climbing taxa have higher species richness than non-climbing sister groups. We evaluated the hypothesis that climbing plant species show greater among-population genetic differentiation than non-climber species. We compared the among-population genetic distance in woody climbers (8 species, 30 populations) and trees (7 species, 29 populations) coexisting in 9 communities in a temperate rainforest. We also compared within-population genetic diversity in co-occurring woody climbers and trees in two communities. Mean genetic distance between populations of climbers was twice that of trees. Isolation by distance (increase in genetic distance with geographic distance) was greater for climbers. Climbers and trees showed similar within-population genetic diversity. Our longevity estimate suggested that climbers had shorter generation times, while other biological features often associated with diversification (dispersal and pollination syndromes, mating system, size and metabolic rate) did not show significant differences between groups. We hypothesize that the greater population differentiation in climbers could result from greater evolutionary responses to local selection acting on initially higher within-population genetic diversity, which could be driven by neutral processes associated with shorter generation times. Increased population genetic differentiation could be incorporated as another line of evidence when testing for key innovations.

攀援习性是植物的一项关键创新（key innovation）：攀援类群的物种丰富度高于非攀援的姊妹类群（sister groups）。我们验证了“攀援植物的种群间遗传分化程度高于非攀援植物”这一假说。我们比较了温带雨林9个共存群落中木质藤本（woody climbers，8个物种、30个种群）与乔木（trees，7个物种、29个种群）的种群间遗传距离。此外，我们还在两个群落中比较了共存的木质藤本与乔木的种群内遗传多样性。藤本种群间的平均遗传距离为乔木的两倍。距离隔离（isolation by distance，即遗传距离随地理距离增加而升高）效应在藤本中更为显著。藤本与乔木的种群内遗传多样性水平相近。我们的寿命估算结果显示，藤本的世代时长更短；而其他通常与物种多样化相关的生物学特征——包括扩散与传粉综合征（dispersal and pollination syndromes）、交配系统（mating system）、体型与代谢速率——在两类群间未表现出显著差异。我们推测，藤本更高的种群分化程度，可能源于其对局部选择的更强演化响应：该响应最初依托于较高的种群内遗传多样性，而该多样性可由与更短世代时长相关的中性过程驱动。在验证关键创新类群时，种群遗传分化程度的提升可作为又一项证据维度。