Periphytic algal community structure in relation to seasonal variation and macrophyte richness in a shallow tropical reservoir

Abstract

The macrophyte structure can influence the development of periphytic algal community in a shallow ecosystem. We investigated the interrelationship between periphytic algal community on artificial substrate and macrophyte species richness during four seasons in a tropical shallow reservoir. The periphyton was evaluated by biomass (as AFDM), algal abundance, species composition, and species richness. Limnological variables and macrophyte coverage were determined at sites with different macrophytes richness in littoral zone. Glass slides were used as the substrate and colonization time was 30 days. Periphytic algal structure was significantly influenced by seasonality and macrophyte richness, as well as the interaction of two factors. Periphytic algal density on natural and artificial substrates was negatively correlated with macrophyte richness and coverage. High biomass, algal biovolume and dominance of Zygnemaphyceae occurred when there was an increase of Utricularia foliosa coverage (summer). Our results showed that the seasonality, and to a lesser extent macrophyte species richness, explained significant portion of the variability of periphyton biomass, algal abundance, and taxonomic composition on artificial substrate. The changes in macrophyte community may have direct consequences on the periphyton structure in a shallow tropical reservoir.