The properties of ecological networks help to understand the patterns of commensal interactions between epiphytes and phorophytes as well as the importance of each species in the structure of the interactions in the community. Consequently, understanding how these interactions occur is extremely important, especially on inselbergs, one of the most threatened ecosystems in the world. In this study, we used connectivity, specialization, nestedness and robustness to investigate the horizontal structure and modularity of the vertical structure in the epiphyte–phorophyte networks in woody vegetation on two inselbergs in the Atlantic Forest in south-eastern Brazil. We found 113 phorophyte individuals in 13 species interacting with 4412 epiphyte individuals in 30 species, with a predominance of bromeliads, orchids and cactus. The networks had a nested horizontal structure, poor connectivity and low specialization. Using a modelling approach, these systems had low robustness when the phorophytes with more interactions were eliminated, being a fragile system in regard to local species loss, with 67% of the species restricted to Pseudobombax, a generalist phorophyte. There was little vertical modularity since many species of epiphytes were found in two or more modules, that we used to describe the vertical phorophyte zones. Highest species richness was found in the lower crown and on surface roots (mainly accidental epiphytes) while abundance had a different pattern, being highest in the upper crown, especially for the bromeliad Tillandsia loliacea. Our results suggest that both size (measured as DBH) as well as the species of phorophyte are important factors in the structuring of epiphyte–phorophyte networks on neotropical inselbergs woody vegetation.

中文翻译：

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热带岛屿木本植被中的共生附生植物-藻类网络：组织和结构模式

生态网络的特性有助于了解附生植物和带生植物之间共生相互作用的模式，以及每个物种在群落相互作用结构中的重要性。因此，了解这些相互作用是如何发生的非常重要，尤其是对于世界上最受威胁的生态系统之一的岛礁。在这项研究中，我们使用连通性、专业化、嵌套性和鲁棒性来研究巴西东南部大西洋森林两个岛内木本植被附生植物 - 浮生植物网络中垂直结构的水平结构和模块性。我们发现 13 个物种的 113 个带生植物个体与 30 个物种的 4412 个附生植物个体相互作用，其中以凤梨科植物、兰花和仙人掌为主。网络具有嵌套的水平结构，连通性差，专业化程度低。使用建模方法，当消除具有更多相互作用的藻类植物时，这些系统的鲁棒性较低，在局部物种损失方面是一个脆弱的系统，67% 的物种仅限于Pseudobombax，一种通才的藻类植物。由于在两个或更多模块中发现了许多附生植物种类，因此几乎没有垂直模块性，我们用它们来描述垂直的带生植物区。下冠和表层根系（主要是偶然的附生植物）的物种丰富度最高，而丰度的模式不同，上冠最高，尤其是凤梨花凤梨。我们的研究结果表明，大小（以 DBH 测量）以及藻类植物的种类都是构建新热带岛木本植物附生植物-藻类网络的重要因素。