Many steppe species reach their (north)westernmost distribution limit in western Central Europe. This also applies to Poa badensis, a rare steppe plant of calcareous rock/sand vegetation. To explore potential differences in reproductive success and genetic composition of peripheral populations, we analysed the absolute (north)westernmost occurrences in Western Germany and populations at the western margin (Eastern Austria) and the centre (Central Hungary) of the Pannonicum, representing a part of the continuous range. Specifically, we discuss the genetic and reproductive constitution of the (north)westernmost exclave and draw conclusions on the species' biogeographical and conservation history in this region. Therefore, we used two independent molecular marker systems (AFLPs, cpDNA sequences) and a set of performance parameters. Overall, lowest regional genetic diversity was found in Western Germany, which is mainly a result of the specific history of two populations. However, this low genetic diversity was not accompanied by reduced reproductive success. The Eastern Austrian populations showed reduced genetic diversity and predominantly reduced performance, interpreted as a consequence of small population sizes. Central Hungarian populations showed the overall highest genetic diversity and comparatively high performance values. We observed high admixture and haplotype sharing between Austrian and Hungarian populations, indicating gene flow among these regions. In contrast, we interpreted the increased population differentiation within, and the clear distinctiveness of the German exclave as a long-term isolation of these (north)westernmost occurrences. Our results, overall, prove the good constitution of these populations and, together with their particular biogeographical history, highlight their conservation value.

中文翻译：

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长期生存和成功保护？遗传多样性较低，但没有证据表明中欧早熟禾（禾本科）最西北分布区边缘的繁殖成功率降低。


许多草原物种在中欧西部达到了最（北）西分布极限。这也适用于早熟禾，一种稀有的钙质岩石/沙植被草原植物。为了探索外围种群繁殖成功率和遗传组成的潜在差异，我们分析了德国西部绝对（西北）最西端的种群以及帕诺尼库姆西缘（奥地利东部）和中心（匈牙利中部）的种群，代表了一部分的连续范围。具体来说，我们讨论了最西（北）飞地的遗传和繁殖构成，并对该地区该物种的生物地理和保护历史得出结论。因此，我们使用了两个独立的分子标记系统（AFLP、cpDNA 序列）和一组性能参数。总体而言，德国西部地区的区域遗传多样性最低，这主要是两个种群特定历史的结果。然而，这种低遗传多样性并没有伴随着繁殖成功率的降低。东奥地利种群表现出遗传多样性减少和性能显着下降，这被解释为种群规模较小的结果。匈牙利中部种群总体上表现出最高的遗传多样性和相对较高的性能值。我们观察到奥地利和匈牙利人群之间存在高度混合和单倍型共享，表明这些地区之间存在基因流动。相比之下，我们将德国飞地内部日益增加的人口分化和明显的独特性解释为这些（北部）最西地区的长期隔离。 总体而言，我们的结果证明了这些种群的良好体质，并结合其特定的生物地理历史，凸显了它们的保护价值。