The plant communities associated with iron-rich outcrops are still little known about to their genetic structure and diversity. Outcrops are often considered to be ‘terrestrial islands’, and gene flow among populations on different outcrops is presumed to be hampered by the isolation effect provided by the surrounding matrix. Here, we studied the genetic diversity and structure of populations of Dyckia excelsa to test the hypothesis that the disjunction of the ironstone outcrops where this species occurs promotes its highly structured genetic variability. Seven nuclear microsatellite markers and two plastid DNA intergenic spacers (rps16-trnK and rpl32-trnL) were used to characterize individuals from seven locations in the region of Urucum Residual Plateau, Mato Grosso do Sul State, Brazil. These markers low haplotype and allelic diversity and high levels of genetic divergence among outcrops, indicating prolonged genetic isolation, with diversification of haplotypes dating from the Pleistocene (1.0 Mya). Pollen movement may occur between neighbouring populations, resulting in a pattern of isolation-by-distance. For conservation purposes, it is recommended that D. excelsa be preserved in situ in each specific location given the low levels of gene flow and the high degree of genetic uniqueness in each group of populations investigated.

中文翻译：

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Dyckia excelsa（凤梨科）是巴西潘塔纳尔铁矿露头上发现的一种濒危物种，具有强大的遗传结构。

与富铁露头有关的植物群落的遗传结构和多样性仍然鲜为人知。露头经常被认为是“陆地岛屿”，而周围露头所提供的隔离效应可能会阻碍不同露头人群之间的基因流动。在这里，我们研究了Dyckia excelsa种群的遗传多样性和结构，以检验以下假设：该物种发生的铁矿露头的分离促进了其高度结构化的遗传变异性。七个核微卫星标记和两个质体DNA基因间隔子（rps16-trnK和rpl32-trnL）用于表征巴西南马托格罗索州南乌鲁库姆残存高原地区七个地点的个体。这些标记物的单倍型和等位基因多样性低，而露头之间的遗传多样性水平高，表明遗传隔离时间延长，并且具有更新世（1.0 Mya）的单倍型。花粉运动可能会在相邻种群之间发生，从而形成距离隔离的模式。为了保护起见，建议在每个特定种群中在每个特定位置就地保存卓越的D. excel，因为它们的基因流动水平较低且遗传独特性很高。