Diversidade e distribuição de epífitas vasculares sobre Cyatheaceae em gradiente altitudinal da floresta ombrófila mista no Paraná, Brasil

Abstract

This study was conducted in a area of approximately 1,877,689 ha in Montana and Alluvial Araucaria Forest, located in the Francisco Paschoetto and Corredor das Águas Conservation Units, at Reserva do Iguaçu, Paraná, in order to present the distribution, frequency and diversity of epiphyte species on Cyatheaceae family phorophytes, verifying the influence of altitude and epiphyte coverage of phorophyte species. Expeditions were carried out at at four different elevations within the study area, and for each elevation a minimum of 20 phorophytes of the Cyatheaceae family were randomly selected and the epiphytic species on them were recorded and analyzed for frequency and coverage. A total of 109 phorophytes were sampled, two belonging to Cyathea feeana and two to Cyathea phalerata, while the remaining majority was represented by Alsophila setosa. A total of 20 species of vascular epiphytes were observed on these phorophytes, belonging to 17 genera and 12 families. The families with the highest species richness were Polypodiaceae with four species and Blechnaceae with three species, followed by Bromeliaceae, Melastomataceae and Piperaceae with two species each, the rest of the families had a single species. Anemochory was found in 65% of species and 40% of species were classified as accidental holoepiphytes. Of the epiphytic species recorded, those with the highest absolute frequency values on the caudices were Philodendron missionum and Polyphlebium angustatum, with 16,97% and 16,06% respectively. The Shannon diversity index estimated for the four altitudinal ranges was H’ = 1,0665 and the evenness J = 0,3560. Philodendron missionum had the highest importance value of the entire sample area, with 21,92. Little significant values of diversity were observed, as well as low influence of altitude and percentage of epiphyte coverage by phorophyte. In addition to the influence of aspects such as the characteristics of phorophytes and epiphytes, the suppression of this vegetation, with the extraction and exploration that previously occurred in the area, may have affected the local conditions of plant development, impacting the diversity of these species. Therefore, it is essential to protect these environments, as they are centers for the dissemination of important species in the biodiversity of the Conservation Units.