The evolutionary split between gymnosperms and angiosperms has far‐reaching implications for the current communities colonizing trees. The inherent characteristics of dead wood include its role as a spatially scattered habitat of plant tissue, transient in time. Thus, local assemblages in deadwood forming a food web in a necrobiome should be affected not only by dispersal ability but also by host tree identity, the decay stage and local abiotic conditions. However, experiments simultaneously manipulating these potential community drivers in deadwood are lacking. To disentangle the importance of spatial distance and microclimate, as well as host identity and decay stage as drivers of local assemblages, we conducted two consecutive experiments, a 2‐tree species and 6‐tree species experiment with 80 and 72 tree logs, respectively, located in canopy openings and under closed canopies of a montane and a lowland forest. We sampled saproxylic beetles, spiders, fungi and bacterial assemblages from logs. Variation partitioning for community metrics based on a unified framework of Hill numbers showed consistent results for both studies: host identity was most important for sporocarp‐detected fungal assemblages, decay stage and host tree for DNA‐detected fungal assemblages, microclimate and decay stage for beetles and spiders and decay stage for bacteria. Spatial distance was of minor importance for most taxa but showed the strongest effects for arthropods. The contrasting patterns among the taxa highlight the need for multi‐taxon analyses in identifying the importance of abiotic and biotic drivers of community composition. Moreover, the consistent finding of microclimate as the primary driver for saproxylic beetles compared to host identity shows, for the first time that existing evolutionary host adaptions can be outcompeted by local climate conditions in deadwood.

中文翻译：

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各分类单元中枯木社区的主要决定因素不同，但在区域上是一致的

裸子植物和被子植物之间的进化分裂对目前树木定居的社区具有深远的影响。枯木的固有特性包括其作为植物组织在空间上分散的栖息地的作用，随时间变化。因此，在坏死生物组中形成食物网的枯木中的局部集合不仅应受到散布能力的影响，而且还应受到寄主树身份，腐烂阶段和局部非生物条件的影响。然而，缺乏同时操纵这些潜在的社区推动者的实验。为了弄清空间距离和微气候的重要性，以及宿主身份和衰退阶段作为局部集合驱动力的重要性，我们进行了两个连续的实验，分别是80棵和72棵原木的2树种和6树种实验，位于树冠开口处以及山地和低地森林的闭合树冠下。我们从原木中取样了甲虫，蜘蛛，真菌和细菌组合。基于希尔数的统一框架进行的社区指标变异划分显示出两项研究的结果一致：寄主身份对于由果皮检测到的真菌组合，腐烂期和寄主树对于DNA检测到的真菌组合，甲虫的小气候和腐烂期最为重要和蜘蛛和细菌的腐烂阶段。空间距离对于大多数分类单元而言次要的并不重要，但对节肢动物的影响最强。在分类单元之间形成鲜明对比的模式凸显了在确定非生物和生物驱动社区组成的重要性时，需要进行多分类单元分析。此外，