Epifitismo vascular em uma floresta de estinga do Brasil subtropical

A phytosociological survey of vascular epiphytes was performed in a sand-dune forest (restinga) of northeastern Rio Grande do Sul, Southern Brazil. A total of 60 host trees (phorophytes) were sampled according to the point-centered quarter method, including trees with at least 10cm of diameter at breast height. The recorded vascular epiphytes belong to 8 families, 20 genera and 31 species, the Orchidaceae and Bromeliaceae being the most diversified. Several additional species were recorded in the whole forest stand with ca. one hectare. Frequency values of vascular epiphytes formed a gradually decreasing sequence of species, the most important being Microgramma vacciniifolia (Polypodiaceae) and Tillandsia eerenthos (Bromeliaceae). The Shannon index of diversity was estimated (H'= 2,990), using frequency on individual phorophytes as a measure of quantitative participation (pi). The number of vascular epiphytes on individual phorophytes ranged from 4 to 16 species, showing a polymodal distribution and a highest modal value of 8 species.