Abstract
Plants from the family Podostemaceae grow on rocks in running water. This study was done in the Paraná River aiming to record the occurrence of Podostemum rutifolium Warm. subsp. rutifolium and to analyze composition, richness and density of the periphytic algae community on this macrophyte. We used a square rubber sampler (25 cm2) and dives in apnea to remove plants attached to the rocks using a putty knife. Later we proceeded to remove and fix, identify and count the algae attached to this substrate. One hundred thirty-seven species of algae were identified and included in nine classes. The highest number of taxa was recorded for Bacillariophyceae, followed by Cyanophyceae. This pattern is found in the majority of lotic environments from the Paraná River floodplain. In spite of being a fouling species, the architecture of P. rutifolium provides microhabitats for many algal species. We strongly suggest that this macrophyte is a key species in periphytic algal community structure, whereas its removal could lead to a decline in periphyton diversity mainly due to the unique presence of P. rutifolium as plant substrate in the sampling area.
Key-words:
Colonization; habitat structure; running water