Abstract Woodland nature reserves must be scientifically assessed so that subsequent management leads to optimal conservation of biodiversity. This entails knowledge of the species composition, the genetics of the local populations and their ecology. Here we assess Tilia species in the Bavarian Forest National Park (BFNP), a large mixed coniferous and deciduous forest in South-Eastern Germany. Tilia occurs here at low density, as in many other mixed forests in Central and Northern Europe. Therefore, results are not only relevant to BFNP but also to other areas. Exhaustive sampling resulted in the collection of 113 mature trees that were genotyped using 20 microsatellite markers, derived from both T. cordata and T. platyphyllos. For the first time, size and aspect of trees, and their community association were contrasted between the species. Genotyping confirmed that T. platyphyllos, T. cordata and their hybrid (T. x europaea) were present in the BFNP and both species deserve conservation. T. platyphyllos has a higher genetic diversity for both sets of markers than T. cordata, confirming earlier work. Both species showed genetic diversity comparable to other populations in Central Europe, which is likely to be sufficient for the maintenance of the species in the short term. However, increasing the number of trees, ensuring local sources are used, and gene flow from surrounding forests over the next decennia may be crucial for long-term survival. Further, within the T. platyphyllos group there was a set of 11 trees that were distinct from the others: they had a lower genetic diversity and were shorter. We hypothesise that these were planted and should not be used for propagation and augmentation. Most saplings analysed appeared to derive from asexual propagation (36 out of 41), although a few (five out of 41) were novel genotypes. This means that, currently, there is some, but rather limited, regeneration. T. cordata was found at a lower altitude and less steep terrain than T. platyphyllos and the hybrid. The hybrid was taller than the two species, while the diameter at breast height was smallest in T. cordata. T. cordata shows a preference for mixed and coniferous forests, while T. platyphyllos occurs mostly in deciduous forests. Our results indicate that biodiversity at the species and genetic level as well as species’ ecology have to be considered in order to guide informed conservation management. These results form the basis to recommend conservation management improving the long-term viability of Tilia in the BFNP and other mixed forests.

中文翻译：

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珍稀树种的知情保护管理需要了解物种组成、遗传特征和生态位

摘要 林地自然保护区必须进行科学评估，以便后续管理能够实现生物多样性的最佳保护。这需要了解物种组成、当地种群的遗传学及其生态。在这里，我们评估了巴伐利亚森林国家公园 (BFNP) 中的椴树物种，这是德国东南部的一个大型针叶和落叶混交林。这里的椴树密度很低，就像在中欧和北欧的许多其他混交林中一样。因此，结果不仅与 BFNP 相关，而且与其他领域相关。详尽的抽样收集了 113 棵成熟的树木，这些树木使用 20 个微卫星标记进行了基因分型，这些标记来自 T. cordata 和 T. platyphyllos。第一次，树木的大小和方面以及它们的群落关联在物种之间进行了对比。基因分型证实 T. platyphyllos、T. cordata 和它们的杂种 (T. x europaea) 存在于 BFNP 中，这两个物种都值得保护。T. platyphyllos 的两组标记都比 T. cordata 具有更高的遗传多样性，这证实了早期的工作。这两个物种都显示出与中欧其他种群相当的遗传多样性，这可能足以在短期内维持该物种。然而，增加树木数量、确保使用当地资源以及在下一个十年中来自周围森林的基因流动可能对长期生存至关重要。此外，在 T. platyphyllos 组中，有一组 11 棵树与其他树不同：它们的遗传多样性较低且较短。我们假设这些是种植的，不应该用于繁殖和增强。大多数分析的树苗似乎来自无性繁殖（41 个中的 36 个），尽管少数（41 个中的 5 个）是新的基因型。这意味着，目前，有一些但相当有限的再生。与 T. platyphyllos 和杂交种相比，T. cordata 被发现在较低的海拔和较不陡峭的地形。杂种比两个物种高，而胸高直径在 T. cordata 中最小。T. cordata 偏爱混交林和针叶林，而 T. platyphyllos 主要出现在落叶林中。我们的结果表明，必须考虑物种和遗传水平以及物种生态的生物多样性，以指导知情保护管理。