Epiphyte-phorophyte relationships: assessing the differences between Seasonal Semideciduous and Swamp Forests in Southeastern Brazil1

ABSTRACT Vascular epiphytes are responsible for a considerable portion of tropical biodiversity; however, the variation of epiphytes-phorophytes relationships in different vegetation types are still poorly understood. In this study, we aimed to assess the presence, abundance, vertical distribution, and life cycle (holoepiphyte and hemiepiphyte) of vascular epiphytes in two vegetation types [Seasonal Semideciduous Forest (- SSF), and Swamp Forest (- SF)] in order to determine any correlation with phorophyte size (diameter and height) and the specificity of phorophyte species to the epiphytic colonization. There was a higher number of phorophytes in SF; however, epiphytes density did not differ between the vegetation types. The recorded vertical distribution also showed different patterns: in the SSF, most epiphytes were found in the canopy, while in the SF they occurred mainly on the trunks of the trees. The abundance of epiphytes was positively correlated with the phorophyte size in the two vegetation types. In the SSF, colonization of phorophytes by epiphytes appeared to be less species-specific than in the SF, where trees density is likely to be a more significant factor to epiphytic colonization. The results showed the importance of the forest heterogeneity in the conservation and maintenance of vascular epiphytes assemblage, demonstrated by differences in the abundance and distribution of the epiphytes, even in contiguous forests.摘要 维管附生植物（vascular epiphytes）构成了热带生物多样性的重要组成部分，但不同植被类型中附生植物与宿主植物（phorophytes）的相互关系变异仍未得到充分阐明。本研究旨在评估两种植被类型——季节性半落叶林（Seasonal Semideciduous Forest，SSF）与沼泽林（Swamp Forest，SF）中维管附生植物的存在情况、丰度、垂直分布格局以及生活史类型（全附生植物（holoepiphyte）与半附生植物（hemiepiphyte）），以此探究其与宿主植物尺寸（胸径与树高）的相关性，以及宿主植物物种对附生定植的特异性。本次调查中，沼泽林的宿主植物个体数更多，但两种植被类型的附生植物密度并无显著差异。记录到的垂直分布格局也存在显著差异：在季节性半落叶林中，多数附生植物分布于林冠层；而在沼泽林中，附生植物主要集中于树干区域。两种植被类型中，附生植物的丰度均与宿主植物尺寸呈正相关。相较于沼泽林，季节性半落叶林中附生植物对宿主植物的定植表现出更低的物种特异性，而沼泽林中树木密度可能是影响附生定植的更关键因素。本研究结果揭示了森林异质性在维管附生植物群落组合的保护与维持中的重要性：即便在连片森林中，附生植物的丰度与分布仍存在显著差异，这也印证了森林异质性的关键作用。