Changes in the taxonomic structure of periphytic algae on a free-floating macrophyte (Utricularia foliosa L.) in relation to macrophyte richness over seasons

ABSTRACT Periphyton has a strong relationship with aquatic macrophytes, which are key components of spatial heterogeneity in the littoral zone. We evaluated the relationship between the community structure of periphytic algae on Utricularia foliosa and macrophyte richness and coverage and limnological variables in a shallow reservoir. Water sampling for physical, chemical and biological analyses was performed at sites with contrasting macrophyte coverage and richness in each of the four main seasons of the year. Periphytic algae were evaluated for density and species composition. High densities of diatoms and filamentous cyanobacteria in the periphyton were observed at sites with high macrophyte coverage and richness, while high abundances of flagellates of Chrysophyceae and Chlorophyceae were found at sites with low macrophyte richness. Light and nutrient availability were determining factors of the temporal variability of the periphytic algae community. We concluded that the interaction between seasonality and spatial heterogeneity (macrophyte community structure and limnological variables), explained the variability in species composition and algal density of the periphyton. Therefore, seasonality and spatial heterogeneity acted as determining factors for periphyton structure on a free-floating macrophyte with high structural complexity