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（serpentine soil）孕育着一类富含特有物种的独特植物区系。本研究以长蕊漆姑草（Minuartia laricifolia）为研究对象，探讨其蛇纹岩特有性的演化历程。该物种具有两个生态特征迥异且分布间断的亚种：原亚种（subsp. laricifolia）分布于西阿尔卑斯山与东比利牛斯山的硅质岩生境，蛇纹岩亚种（subsp. ophiolitica）则仅见于北亚平宁山脉的蛇纹岩土生境。我们对30个种群的扩增片段长度多态性（AFLP）标记与叶绿体序列进行分析，解析该类群的系统发育关系，以及第四纪气候变化对其当前分布格局与生态适应性的影响。基于AFLP数据的贝叶斯种群结构聚类分析（BAPS）将长蕊漆姑草划分为4个类群：其中1个类群仅包含蛇纹岩亚种，而原亚种内部可进一步划分为3个类群，即滨海阿尔卑斯类群、西北阿尔卑斯类群与中央阿尔卑斯类群。邻接进化树（neighbour-joining tree）分析得到了与之一致的类群划分结果，但蛇纹岩亚种嵌套于原亚种的滨海阿尔卑斯类群之中。蛇纹岩亚种共携带3种不同的叶绿体单倍型（chloroplast haplotype），且这些单倍型同样存在于原亚种的滨海阿尔卑斯类群中。鉴于蛇纹岩亚种具有较高的遗传多样性，其起源更可能源于原亚种的异域分化（vicariance），而非长距离扩散（long-distance dispersal）事件。遗传与地理证据均表明，原亚种的滨海阿尔卑斯种群是蛇纹岩亚种的最近缘类群。我们提出如下假说：在冰川期植被覆盖更为开阔的时期，长蕊漆姑草亦可在北亚平宁山脉的非蛇纹岩生境中存活；但由于在更适宜的生境中受到竞争排除（competitive exclusion），仅适应蛇纹岩土的种群得以延续至今。