Data from: The origin of the serpentine endemic Minuartia laricifolia subsp. ophiolitica by vicariance and competitive exclusion

Serpentine soils harbour a unique flora that is rich in endemics. We examined the evolution of serpentine endemism in Minuartia laricifolia, which has two ecologically distinct subspecies with disjunct distributions: subsp. laricifolia on siliceous rocks in the western Alps and eastern Pyrenees and subsp. ophiolitica on serpentine in the northern Apennines. We analysed AFLPs and chloroplast sequences from 30 populations to examine their relationships and how their current distributions and ecologies were influenced by Quaternary climatic changes. Minuartia laricifolia was divided into four groups with a BAPS cluster analysis of the AFLP data, one group consisted only of subsp. ophiolitica, while three groups were found within subsp. laricifolia: Maritime Alps, north-western Alps and central Alps. The same groups were recovered in a neighbour-joining tree, although subsp. ophiolitica was nested within the Maritime Alps group of subsp. laricifolia. Subspecies ophiolitica contained three different chloroplast haplotypes, which were also found in the Maritime Alps group of subsp. laricifolia. Given its high genetic diversity, subsp. ophiolitica appears to have arisen from subsp. laricifolia by vicariance instead of by long-distance dispersal. Genetic and geographic evidence point to the Maritime Alps populations of subsp. laricifolia as the closest relatives of subsp. ophiolitica. We hypothesize that M. laricifolia was also able to grow on nonserpentine rocks in the northern Apennines during glacial periods when the vegetation was more open, but that only the serpentine-adapted populations were able to persist until the present due to their competitive exclusion from more favourable habitats.

蛇纹岩土壤（serpentine soils）孕育着一类富含特有种的独特植物区系。本研究以laricifolia漆姑（Minuartia laricifolia）为研究对象，探讨其蛇纹岩特有性状的演化历程。该物种包含两个生态特征迥异且分布间断的亚种：分布于西阿尔卑斯山脉与东比利牛斯山脉硅质岩（siliceous rocks）上的laricifolia亚种（subsp. laricifolia），以及栖息于北亚平宁山脉蛇纹岩土壤中的ophiolitica亚种（subsp. ophiolitica）。研究人员对30个种群的扩增片段长度多态性（AFLPs）与叶绿体序列进行了分析，以揭示其亲缘关系，以及第四纪气候变化（Quaternary climatic changes）如何影响其当前分布与生态特征。基于AFLP数据的贝叶斯群体结构聚类分析（BAPS）将laricifolia漆姑划分为4个类群：其中1个类群仅包含ophiolitica亚种，而laricifolia亚种内部可分为3个类群，分别为滨海阿尔卑斯类群、西北阿尔卑斯类群与中阿尔卑斯类群。邻接进化树（neighbour-joining tree）分析得到了一致的类群划分结果，但ophiolitica亚种嵌套于laricifolia亚种的滨海阿尔卑斯类群中。ophiolitica亚种包含3种不同的叶绿体单倍型（chloroplast haplotypes），这些单倍型同样存在于laricifolia亚种的滨海阿尔卑斯类群中。鉴于ophiolitica亚种具有较高的遗传多样性，其大概率是通过异域分化（vicariance）而非长距离扩散（long-distance dispersal）从laricifolia亚种演化而来。遗传与地理学证据均表明，laricifolia亚种的滨海阿尔卑斯种群是ophiolitica亚种的最近缘类群。本研究提出假说：在冰期植被更为开阔的时期，laricifolia漆姑也可在北亚平宁山脉的非蛇纹岩岩石上生长，但由于在更适宜的生境中受到竞争排斥（competitive exclusion），仅适应蛇纹岩土壤的种群得以存续至今。