Forest canopies host an abundant but often neglected diversity of arthropods, which requires careful attention in times of ongoing biodiversity loss. Yet, how tree species composition interacts with canopy structure in shaping arthropod communities remains largely unknown. Here, by combining mobile laser scanning and insecticidal fogging with a machine learning algorithm, we studied which canopy architectural properties affect canopy arthropod communities in monospecific and mixed stands of broadleaved European beech and the coniferous Norway spruce and non-native Douglas fir in Germany. Evaluating the abundances and ecological guild diversity of ∼ 90,000 arthropods and 27 partly novel high-resolution structural variables, we identified vegetation volume and tree species identity as weak predictors of arthropod abundance and ecological guild diversity. In contrast, structural heterogeneity, i.e. structural complexity, vertical layering and variability of canopy gaps—which were highest in coniferous stands—were strong positive drivers. Despite this, arthropod ecological guild diversity was lower in non-native Douglas fir. Mixed stands had intermediate arthropod abundance and ecological guild diversity. Our study shows that habitat heterogeneity and tree species-identity are closely interlinked in shaping associated canopy arthropod communities. Positive effects of habitat heterogeneity on arthropod ecological guild diversity were often uncoupled from resource availability, and the key role of our novel intra-canopy gap indices suggests that they should be considered as indicators in future research on forest heterogeneity-diversity relationships. Broadleaf-conifer mixtures may be suitable to mediate negative tree-species identity effects when adapting forests to global change.

中文翻译：

---

冠层结构影响树木身份效应内外的节肢动物群落：结合激光雷达数据、杀虫雾化和机器学习回归模型的见解

森林树冠拥有丰富但经常被忽视的节肢动物多样性，在生物多样性持续丧失的时期需要密切关注。然而，树种组成如何与树冠结构相互作用以塑造节肢动物群落仍然很大程度上未知。在这里，通过将移动激光扫描和杀虫雾化与机器学习算法相结合，我们研究了哪些树冠结构特性影响欧洲阔叶山毛榉、挪威针叶云杉和德国非本土花旗松的单种和混合林中的树冠节肢动物群落。通过评估约 90,000 种节肢动物的丰度和生态群多样性和 27 个部分新颖的高分辨率结构变量，我们确定植被体积和树种身份是节肢动物丰度和生态群多样性的弱预测因子。相比之下，结构异质性，即结构复杂性、垂直分层和冠层间隙的变异性（在针叶林中最高）是强有力的积极驱动因素。尽管如此，非本地花旗松的节肢动物生态群多样性较低。混合林具有中等节肢动物丰度和生态群多样性。我们的研究表明，栖息地异质性和树种同一性在塑造相关的冠层节肢动物群落方面密切相关。栖息地异质性对节肢动物生态群落多样性的积极影响往往与资源可用性无关，我们新颖的冠层内差距指数的关键作用表明，它们应被视为未来森林异质性-多样性关系研究的指标。当森林适应全球变化时，阔叶-针叶树混合物可能适合调节树种特性的负面影响。