Floristic composition and structure of the vascular epiphytical component in a remnant of Araucaria Rainforest in Curitiba, Paraná

Abstract

A survey of the floristic and phytosociological structure of the vascular epiphytic component a fragment of the Araucaria Rainforest in the municipality of Curitiba was carried out. For the phytosociological sampling, 20 phorophytes were selected, which were divided into 6 ecological zones, with scores referring to the dominance and coverage of the species in each zone. The value of ecological importance (VIE) was calculated based on the relative values of frequency, coverage and dominance. 80 vascular species, 51 genera and 22 families were found. Orchidaceae was the richest family with 26 species (32.5%), followed by Polypodiaceae with 12 (15%). The richest genera were Acianthera with 6 species (7.5%) and Pleopeltis with 5 ones (6.3%) each. In the structural analysis, 51 species and 17 families were registered. The Shannon index (H ') estimated for the sampling was 3.63 nats.ind-1 and the equity (J') was 0.92. Most species (75%) are characteristic holoepiphytes, while ephemeral hemiepiphytes and epiphytes were insignificant, with only 11.3% and 5%, respectively. The species with the greatest structural importance accounted for 78.8% of the VIE. Microgramma squamulosa and Lepismium warmingianum were the most important, with VIE greater than 7% each, Campyloneurum nitidum was the most important in the base of the shaft. Four families stood out: Polypodiaceae with VIE of 28.2%, Bromeliaceae with VIE 19.8%, Cactaceae with VIE 19.2% and Orchidaceae with VIE 17.3%, adding 84.6% of VIE. Most of the records occurred in the coverage classes 0-5 and 6- 10%, which account for 94.9% of the records. Regarding dominance, 87.1% of epiphyte records received a score of 1 or 2 (reduced size and biomass) and only 2.8% received a score of 9 or 15 (expressive size and biomass) with emphasis on Heptapleurum arboricola, an invasive exotic species. The middle canopy was the one with the greatest dominance, wealth and diversity. It is concluded that the epiphytic community showed high diversity and richness, in addition to a well-developed phytosociological structure. The middle and inner canopy were the areas of the tree with the greatest diversity and the most developed structure.

Keywords:
Epiphytic flora; Phytosociology; Araucaria Forest