Species Diversity and Abundance of Vascular Epiphytes on Vellozia piresiana in Brazil1

Abstract

ABSTRACTThe composition, structure, and ecology of epiphyte communities have been intensely studied in tropical rain forests. Studies involving epiphytes, however, are scarce in other vegetational physiognomies. This study examined the composition of an epiphyte community on Vellozia piresiana (Velloziaceae) in a Brazilian rupestrian field, and investigated the factors influencing their abundance and distribution. In July 1998, 98 individuals of V. piresiana were sampled inside three transects in rocky outcrops of Serra do Cipó, Minas Gerais, and their height were measured. All epiphytes growing on these phorophytes were counted and identified. Height and branch diameter at which each epiphyte individual occurred were recorded. Luminosity intensity was measured in the upper canopy, middle canopy, and 10 cm above ground 100 phorophytes in the same population; 712 epiphytes were found growing on V. piresiana belonging to six species: Vrisea oligantha (Bromeliaceae; 344 individuals), Epidendrum saxatile (251), Constancia ci‐poencis (50), Prosthechea vespa (31) Sophronites brevipedunculata (30; all Orchidaceae), and Tillandsia usneoides (1; Bromeliaceae). A higher abundance of epiphytes occurred at intermediate heights on the phorophytes, probably because of an intermediate light incidence at these positions. We found epiphytic species across different distributions, both in terms of height and branch diameter of V, piresiana, which may have reflected distinct degrees of tolerance to drought and excessive luminosity. These results indicated that despite the low richness observed in this study, the epiphyte community on V. piresiana presented ecological features similar to that observed for tropical rain forests (e.g., phorophyte partitioning and differential vertical distribution).RESUMESThe composition, structure, and ecology of epiphyte communities have been intensely studied in tropical rain forests. Studies involving epiphytes, however, are scarce in other vegetational physiognomies. This study examined the composition of an epiphyte community on Vellozia piresiana (Velloziaceae) in a Brazilian rupestrian field, and investigated the factors influencing their abundance and distribution. In July 1998, 98 individuals of V. piresiana were sampled inside three transects in rocky outcrops of Serra do Cipó, Minas Gerais, and their height were measured. All epiphytes growing on these phorophytes were counted and identified. Height and branch diameter at which each epiphyte individual occurred were recorded. Luminosity intensity was measured in the upper canopy, middle canopy, and 10 cm above ground 100 phorophytes in the same population; 712 epiphytes were found growing on V. piresiana, belonging to six species: Vrisea oligantha (Bromeliaceae; 344 individuals), Epidendrum saxatile (251), Constancia ci‐poencis (50), Prosthechea vespa (31) Sophronites brevipedunculata (30; all Orchidaceae), and Tillandsia usneoides (1; Bromeliaceae). A higher abundance of epiphytes occurred at intermediate heights on the phorophytes, probably because of an intermediate light incidence at these positions. We found epiphytic species across different distributions, both in terms of height and branch diameter of V, piresiana, which may have reflected distinct degrees of tolerance to drought and excessive luminosity. These results indicated that despite the low richness observed in this study, the epiphyte community on V. piresiana presented ecological features similar to that observed for tropical rain forests (e.g., phorophyte partitioning and differential vertical distribution).