Edge effect in vascular epiphytes in a mixed ombrophilous forest, Rio Grande do Sul, Brazil

DOI: 10.15343/0104-7809.200832.3.8

Abstract

This inquiry had as its aim to characterize the edge effect of edge on vascular epiphytes in a fragment of 53 hectare of a mixed
ombrophilous forest located in Maximiliano de Almeida, Rio Grande do Sul. A quantitative survey of epiphytes was carried out in an area of 0,2
hectare, distributed in four retorts of five meters of width by 100 meters of length, and transects were subdivided in 50 square-meter pieces. We
considered as a local of introduction of vascular epiphytes arboreal phorophytes using as a criterion of inclusion a diameter at breast height or
equal to 4.77 cm and these were divided vertically in four regions: inferior half of the trunk; superior half of the trunk; primary branches and
external branches. For each piece of the sample we collected data related to brightness, moisture and temperature. Each species received a grade
referring to its respective abundance. We used the Total Value (tv – sum of the grades obtained by the species) to analyze the distribution of vascular
epiphytes in the gradient. In the present study there were identified, in 193 phorophytes, 18 species and 7 families distributed in a gradient
edge/interior. Statistical analyses showed a significant correlation between epiphytes total value and brightness. Other abiotic variables did not
present significant correlation with the biological components. Frequency data show that 70% of sampled individuals take place between 10 and
60 meters of distance from the edge and that from 18 considered species, 10 take place exclusively or present more than 70% of the total value
in this passage of the gradient edge/interior. Results obtained indicate that brightness is the main abiotic variable related to the distribution and
the of vascular epiphytic individuals’ frequency in the analyzed gradient.