Habitat trees, which provide roosting, foraging and nesting for multiple taxa, are retained in managed forests to support biodiversity conservation. To what extent their spatial distribution influences provisioning of habitats has rarely been addressed. In this study, we investigated whether abundance and richness of tree-related microhabitats (TreMs) differ between habitat trees in clumped and dispersed distributions and whether the abundance of fifteen groups of TreMs is related to tree distribution patterns. To identify habitat trees, we quantified TreMs in temperate mountain forests of Germany. We determined clumping (the Clark–Evans index), size of the convex hull, diameter at breast height, as well as altitude, slope and aspect of sites for their possible influence on TreMs. We additionally determined the difference in TreM abundance and richness among four options of selecting five habitat trees per ha from 15 candidates: (a) the most clumped trees, (b) five randomly selected and dispersed trees, (c) the single tree with highest abundance or richness of TreMs and its four closest neighbors and (d) a “reference selection” of five trees with known highest abundance or richness of TreMs irrespective of their distribution. The degree of clumping and the size of the convex hull influenced neither the abundance nor richness of TreMs. The reference selection, option (d), contained more than twice the number of TreMs compared to the most clumped, (a), or random distributions, (b), of five habitat trees, while option (c) assumed an intermediate position. If the goal of habitat tree retention is to maximize stand-level abundance and richness of TreMs, then it is clearly more important to select habitat trees irrespective of their spatial pattern.

中文翻译：

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与树木相关的微型栖息地的保留更多地取决于栖息地树木的选择，而不是它们的空间分布

栖息地树木为多种分类群提供栖息、觅食和筑巢，被保留在受管理的森林中，以支持生物多样性保护。它们的空间分布在多大程度上影响了栖息地的供应，很少有人讨论。在这项研究中，我们调查了树木相关微生境 (TreM) 的丰度和丰富度在丛生和分散分布的栖息地树木之间是否不同，以及十五组 TreM 的丰度是否与树木分布模式有关。为了识别栖息地树木，我们量化了德国温带山林中的 TreM。我们确定了结块（Clark-Evans 指数）、凸包的大小、胸高直径，以及海拔、坡度和场地方面，以了解它们对 TreM 的可能影响。我们还确定了从 15 个候选树中每公顷选择 5 棵栖息地树的四个选项之间 TreM 丰度和丰富度的差异：（a）最丛生的树，（b）随机选择和分散的 5 棵树，（c） TreMs 及其四个最近邻居的丰度或丰富度，以及 (d) 已知最高 TreMs 丰度或丰富度的五棵树的“参考选择”，而不管它们的分布如何。结块的程度和凸包的大小既不影响 TreMs 的丰度，也不影响 TreM 的丰富度。参考选择选项 (d) 包含的 TreM 数量是五棵栖息地树中最密集的 (a) 或随机分布 (b) 的两倍多，而选项 (c) 则处于中间位置。