The great heterogeneity of tropical systems challenges our understanding of how niche and neutral processes structure epiphyte communities. Dispersal, phorophyte identity and the environmental conditions created by phorophytes are the main determinants of vascular epiphyte structure and diversity. However, these forces comprise multiple causal factors that need to be decomposed to address the complex patterns of independent and confounded effects acting upon epiphyte communities. We tested the hypothesis that the environment created by phorophytes (size, bark characteristics, microenvironmental conditions, and substrate type) is more important than phorophyte species identity and space in determining the structure of epiphyte communities, with phorophyte size being a major determinant within the environmental component. We also expected larger phorophytes to exhibit greater epiphyte richness and diversity. The study was carried out on an inselberg within a semi-deciduous montane forest and a cloud forest in southeastern Brazil. Partial redundancy analysis was used to hierarchically decompose the relative abundances of vascular epiphytes into three components: association with particular phorophyte species, the environment created by phorophytes, and space (Moran’s eigenvector maps). Linear models were used to analyze the relationship between epiphytic diversity and richness with size descriptors. We show that neutral and niche-based processes act simultaneously on the dynamics of vascular epiphyte species, but distinctly on the inselberg and cloud forest. The potential for an epiphyte to occupy all favorable phorophytes was larger in the cloud forest due to the higher connectivity offered by trees. Abundance, richness and diversity of epiphytes increased with phorophyte size, probably due to an increase in the area, time of colonization or increase in microhabitat heterogeneity within phorophytes. Larger phorophytes are a major determinant of local environmental conditions and the spatial organization of epiphytes, as they promote their abundance and maintain their diversity in tropical systems.

热带系统的巨大异质性挑战了我们对生态位和中性过程如何构建附生植物群落的理解。散布、叶状植物身份和叶状植物创造的环境条件是维管附生植物结构和多样性的主要决定因素。然而，这些力量包括多个因果因素，需要分解这些因素以解决作用于附生植物群落的独立和混杂影响的复杂模式。我们检验了以下假设：在确定附生植物群落的结构方面，由叶状植物创造的环境（大小、树皮特征、微环境条件和基质类型）比叶状植物物种身份和空间更重要，其中叶状植物的大小是环境中的主要决定因素。成分。我们还预计较大的叶生植物会表现出更大的附生植物丰富度和多样性。该研究是在巴西东南部半落叶山地森林和云雾林内的一个山上进行的。部分冗余分析用于将维管附生植物的相对丰度分层分解为三个组成部分：与特定植物种类的关联、由植物创造的环境和空间（莫兰的特征向量图）。线性模型用于分析附生多样性和丰富度与大小描述符之间的关系。我们表明，中性和基于生态位的过程同时作用于维管附生物种的动态，但明显作用于岛礁和云雾林。由于树木提供更高的连通性，附生植物占据所有有利的叶状植物的潜力在云林中更大。附生植物的丰度、丰富度和多样性随着叶状植物的大小而增加，这可能是由于面积、定植时间的增加或叶状植物内微生境异质性的增加。较大的叶生植物是当地环境条件和附生植物空间组织的主要决定因素，因为它们在热带系统中促进了它们的丰度并保持了它们的多样性。