Department of Conservation Ecology and Entomology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa.
Sci Rep. 2020 Nov 16;10(1):19905. doi: 10.1038/s41598-020-76868-8.
Biodiversity studies on forest canopies often have narrow arthropod taxonomic focus, or refer to a single species of tree. In response, and to better understand the wide range of drivers of arthropod diversity in tree canopies, we conducted a large-scale, multi-taxon study which (a) included effect of immediate surroundings of an individual tree on plant physiological features, and (b), how these features affect compositional and functional arthropod diversity, in a warm, southern Afro-temperate forest. We found that tree species differed significantly in plant physiological features and arthropod diversity patterns. Surprisingly, we found negative correlation between surrounding canopy cover, and both foliar carbon and arthropod diversity in host trees, regardless of tree species. Subtle, tree intraspecific variation in physiological features correlated significantly with arthropod diversity measures, but direction and strength of correlations differed among tree species. These findings illustrate great complexity in how canopy arthropods respond to specific tree species, to immediate surroundings of host trees, and to tree physiological features. We conclude that in natural forests, loss of even one tree species, as well as homogenization of the crown layer and/or human-induced environmental change, could lead to profound and unpredictable canopy arthropod biodiversity responses, threatening forest integrity.
森林冠层的生物多样性研究通常对节肢动物的分类关注范围较窄，或者仅针对某一种树。有鉴于此，为了更好地理解树冠层中节肢动物多样性的广泛驱动因素，我们进行了一项大规模的多分类群研究，该研究（a）包括个体树周围环境对植物生理特征的影响，以及（b）这些特征如何影响组成和功能上的节肢动物多样性，研究地点在温暖的南部非洲温带森林。我们发现，树种在植物生理特征和节肢动物多样性模式上存在显著差异。令人惊讶的是，我们发现无论树种如何，周围树冠覆盖度与寄主树木的叶片碳和节肢动物多样性均呈负相关。树木种内生理特征的细微差异与节肢动物多样性指标显著相关，但相关性的方向和强度在树种之间存在差异。这些发现表明，树冠节肢动物对特定树种、寄主树木周围环境以及树木生理特征的响应具有很大的复杂性。我们的结论是，在自然森林中，即使失去一种树种，以及树冠层的同质化和/或人为引起的环境变化，都可能导致树冠节肢动物生物多样性产生深远且不可预测的响应，从而威胁到森林的完整性。
