Disentangling the effects of tree-species and microclimate on multi-trophic diversity in dead-wood

森林拥有全球碳储量的主要部分，并栖息着相当数量的陆地生物多样性。在所有营养级别的所有森林栖息地中，至少有四分之一的分类群直接或间接依赖枯木。决定枯木生物多样性的两个主要因素是小气候和寄主树种，它们对不同营养水平的不同分类群具有不同的重要性。然而，目前尚不清楚寄主树种和小气候的影响是随着营养水平的增加而减少还是增加。拟议的项目将测试a)小气候对物种多样性和网络多样性(即营养级别之间的相互作用的数量)的重要性是否随着营养级别的增加而降低，以及b)寄主树木属性对物种多样性和网络多样性的重要性是否随着营养级别的增加而减少。因此，已经建立了两个独特的实验装置，允许解开树种和阳光照射的影响。在第一次试验中，6个树种的108根原木被暴露在封闭的树冠下、开阔的草地上和人工遮荫下(6块样地18块样地)。在第二次试验中，42个树种的枝束在3个日照小区和3个遮荫小区进行了暴露。下一代测序将用于识别微生物多样性以及微型节肢动物的多样性。所获得的数据将用基于Hill数的前沿网络多样性方法进行分析，以了解小气候和寄主树种对多个营养水平下腐植酸生物多样性的影响。

Forests harbour major parts of global carbon stock and inhabit a significant amount of terrestrial biodiversity. A minimum of one quarter of all forest dwelling-taxa in all trophic levels depend directly or indirectly on deadwood. Two main factors that determine biodiversity in deadwood are microclimate and host tree species with varying importance to different taxonomic groups in different trophic levels. However, it remains unclear if the effect of host tree species and microclimate decrease or increase along with increase in trophic levels. The proposed project will test if a) the importance of microclimate on species diversity and network diversity (i.e. number of interactions between trophic levels) decrease with increasing trophic level, and if b) the importance of host tree properties on species diversity and network diversity decrease with increasing trophic level. Therefore, two unique experimental setups which allow to untangle the effects of tree species and sun exposure have been established. In the first experiment, 108 logs of six tree species have been exposed under closed canopies, on open meadows and under artificial shade (18 subplots arranged in six plots). Branch-bundles of 42 tree species were exposed on three sun-exposed and three shaded plots in the second experiment. Next generation sequencing will be used to identify microbial diversity as well as diversity of micro-arthropods. The obtained data will be analyzed with a cutting-edge network diversity approach based on Hill numbers to untangle the influence of microclimate and host tree species on diversity of saproxylic organisms in multiple trophic levels.