Data from: Fine partitioning of epiphyte habitat within Johansson zones in tropical Australian rainforest trees

For over three decades, the Johansson zones have been widely used in epiphyte studies as a way of stratifying the host tree into habitat zones, however, the usefulness of this system has been questioned. We test the effectiveness of the Johansson zones by grouping epiphyte species by the substrate and microclimatic attributes of their individual occurrences and assessing the fidelity of these groups to the Johansson zones. Habitat characteristics were recorded for every individual epiphyte on 30 trees in the lower montane rainforests of north-eastern Australia. Twenty-four epiphyte species were agglomerated into four groups using Ward’s method. Group 4 was highly distinct and included shade loving species and nomadic vines from the lower zones of the host trees. Group 3 contained species from the most exposed habitats. Group 1 had higher light levels and lower substrate thickness than Group 2, yet both groups had close to identical distributions over the Johansson zones. This suggests that groups of epiphyte species may utilise different micro-sites within the same zone. While the Johansson zones are a useful tool in epiphyte studies, finer partitioning of habitat within the host tree may be missed.三十余年来，约翰松分区(Johansson zones)作为将宿主树划分为生境分区的常用方法，被广泛应用于附生植物(epiphyte)研究领域，不过该分区系统的实用性近年来受到了质疑。本研究通过将附生植物按其个体出现位置的基质与微气候属性进行聚类，并评估这些聚类类群与约翰松分区的契合程度，以此检验约翰松分区的有效性。研究人员对澳大利亚东北部低山雨林中30棵宿主树上的每一株附生植物的生境特征进行了详细记录。本研究采用沃德法(Ward’s method)将24种附生植物划分为4个类群：类群4特征极为鲜明，涵盖喜阴物种与源自宿主树下部分区的蔓生藤本；类群3包含来自光照最充足生境的物种；类群1的光照水平高于类群2，但基质厚度更低，然而两类群在约翰松分区中的分布几乎完全一致。这表明，同一约翰松分区内的附生植物类群可能利用了不同的微生境。尽管约翰松分区仍是附生植物研究中的实用工具，但该系统或会遗漏宿主树内生境的更精细划分。