Vertical explorers: Unraveling vertical and horizontal patterns of vascular epiphyte diversity in a dwarf cloud forest

Abstract

Vascular epiphytes are plants that grow on phorophytes, and their distribution may vary both horizontally and vertically. Understanding the factors shaping epiphyte distribution and their relationship with alpha and beta diversities is crucial for understanding richness and composition patterns. We investigated alpha and beta diversity variation in the vertical and horizontal stratification of epiphyte communities across different vegetation types in a dwarf cloud forest. Twenty-four 20 × 10 m plots were established in three vegetation types defined by distinct soil characteristics, different phorophyte height and differences in tree species composition in Parque Estadual do Ibitipoca, Minas Gerais, Brazil. Phorophytes were divided into four strata: (A) base of the trunk, (B) lower trunk, (C) inner canopy, and (D) outer canopy. Alpha and beta diversity analyses were performed for each site. We found a reduced stratification in the area, indicating minimal composition differences between the strata. However, the canopy exhibited greater species richness than the trunk. Vegetation types F1 and F2 displayed higher richness compared to F3. Orchidaceae was the richest family overall, while Bromeliaceae and Polypodiaceae were more frequent. Holoepiphytes were highly representative, demonstrating consistent patterns of richness, composition, and dispersion, with anemochorous species being the most abundant. This study highlights the unique patterns of epiphyte stratification, emphasizing the importance of biotic and abiotic characteristics in colonization processes. Despite the low canopy of the forest, the non-uniformity in stratification demonstrates that formation characteristics, such as height, play a significant role in shaping epiphyte richness and composition patterns.