Data from: Genetic diversity and divergence in populations of the threatened grassland perennial Vincetoxicum atratum (Apocynaceae-Asclepiadoideae) in Japan

We examined the genetic diversity and structure in populations of the endangered grassland herb Vincetoxicum atratum using 11 polymorphic microsatellite loci. Although the populations were small and disconnected, our molecular data indicated that the species maintains relatively high levels of genetic diversity and connectivity among populations. Population clustering analyses detected two to three clusters and most of the populations of V. atratum comprised admixture of these genetic clusters. These admixtures likely formed during the process of colonizing habitats that had been disturbed by human activities. However, STRUCTURE clustering detected low-admixtures in populations occurring in rocky maritime sites, which may not be suitable for agriculture/rangeland activities. High genetic diversity and population connectivity suggested that loss of the remaining populations by grassland reduction might be an immediate threat for this species. Small grasslands populations managed by local farmers need appropriate conservation practices. Although our results showed genetic diversity and gene flow among populations of V. atratum were high, it is possible that this resulted from the historical continuous distribution of the species. To examine this hypothesis, further periodical monitoring of the genetic diversity and the genetic differentiation for the species is needed for a conservation action of the species.

本研究采用11个多态性微卫星位点（microsatellite loci），对濒危草原草本植物黑花徐长卿（Vincetoxicum atratum）的种群遗传多样性与种群遗传结构进行了分析。尽管该物种种群规模狭小且生境片段化，本研究的分子数据却显示，该物种仍维持着较高水平的遗传多样性与种群间连通性。种群聚类分析（population clustering analyses）结果显示，该物种可划分为2至3个遗传聚类组，且多数黑花徐长卿种群均呈现这些遗传聚类组的遗传混合特征。此类遗传混合现象大概率形成于该物种定植受人类活动干扰生境的过程中。不过，STRUCTURE聚类分析发现，生长在岩质滨海生境（此类生境通常不适宜农业或牧场活动）的种群遗传混合程度较低。较高的遗传多样性与种群连通性表明，草地缩减导致的现存种群丧失可能是该物种面临的直接威胁。由当地农户管护的小型草原种群亟需针对性的保护措施。尽管本研究结果显示黑花徐长卿种群间的遗传多样性与基因流水平较高，但该现象可能源于该物种历史上的连续分布格局。为验证这一假说，后续需对该物种的遗传多样性与遗传分化开展周期性监测，以制定科学的物种保护方案。