Alsophila setosa Kaulf. is a tree fern occurring in the primary and secondary forest formations in South and Southeastern Brazil. The present study discusses population structure, architecture of the underground parts as well as herbivory of fronds and epiphytic species. Fieldwork was performed in two secondary forest tracts in the municipalities of Morro Reuter and Sapiranga in the state of Rio Grande do Sul, Brazil. Contiguous 100 m² plots were surveyed as to the occurrence of A. setosa and plants sizes. Two samples, of 45 plants in Morro Reuter and 48 in Sapiranga, were examined throughout a full year cycle as to herbivory on their fronds. Five plants were uprooted for the study of the underground structures. The epiphytic plants on the caudexes were recorded and sampled. The underground structure is complex, with caulinar branches that may form new plants, leading to an increase of the number of individuals in a stand and to an aggregate spatial distribution. A larger number of smaller plants was recorded. Herbivory damage was observed on 28.88% of the plants in Morro Reuter and 35.41% in Sapiranga. As to vascular epiphytes, 16 species were found, with a predominance of holoepiphytes. This role as phorophyte is of special importance for the conservation of some the epiphytic species.
Ecology; epiphytic pteridophytes; population structure; herbivory; tree fern
