Conservation management can be aided by knowledge of genetic diversity and evolutionary history, so that ecological and evolutionary processes can be preserved. The Button Wrinklewort daisy (Rutidosis leptorrhynchoides) was a common component of grassy ecosystems in south-eastern Australia. It is now endangered due to extensive habitat loss and the impacts of livestock grazing, and is currently restricted to a few small populations in two regions >500 km apart, one in Victoria, the other in the Australian Capital Territory and nearby New South Wales (ACT/NSW). Using a genome-wide SNP dataset, we assessed patterns of genetic structure and genetic differentiation of 12 natural diploid populations. We estimated intrapopulation genetic diversity to scope sources for genetic management. Bayesian clustering and principal coordinate analyses showed strong population genetic differentiation between the two regions, and substantial substructure within ACT/NSW. A coalescent tree-building approach implemented in SNAPP indicated evolutionary divergence between the two distant regions. Among the populations screened, the last two known remaining Victorian populations had the highest genetic diversity, despite having among the lowest recent census sizes. A maximum likelihood population tree method implemented in TreeMix suggested little or no recent gene flow except potentially between very close neighbours. Populations that were more genetically distinctive had lower genetic diversity, suggesting that drift in isolation is likely driving population differentiation though loss of diversity, hence re-establishing gene flow among them is desirable. These results provide background knowledge for evidence-based conservation and support genetic rescue within and between regions to elevate genetic diversity and alleviate inbreeding.

遗传多样性和进化史的知识可以帮助保护管理，从而保护生态和进化过程。Button Wrinklewort 雏菊 ( Rutidosis leptorrhynchoides) 是澳大利亚东南部草地生态系统的常见组成部分。由于广泛的栖息地丧失和牲畜放牧的影响，它现在濒临灭绝，目前仅限于相距 >500 公里的两个地区的少数小种群，一个在维多利亚，另一个在澳大利亚首都地区和附近的新南威尔士州（行动/新南威尔士州）。使用全基因组 SNP 数据集，我们评估了 12 个自然二倍体种群的遗传结构和遗传分化模式。我们估计了种群内的遗传多样性，以确定遗传管理的来源。贝叶斯聚类和主坐标分析显示这两个地区之间存在强烈的种群遗传分化，并且 ACT/NSW 内有大量子结构。在 SNAPP 中实施的合并树构建方法表明两个遥远区域之间存在进化差异。在筛选的人群中，尽管最近的人口普查规模最小，但最后两个已知的维多利亚人口具有最高的遗传多样性。在 TreeMix 中实施的最大似然种群树方法表明最近的基因流动很少或没有，除非可能在非常近的邻居之间。在遗传上更具差异性的种群具有较低的遗传多样性，这表明孤立漂移可能通过多样性的丧失来推动种群分化，因此在它们之间重建基因流动是可取的。