Controlling Harmful Cyanobacteria: Taxa-Specific Responses of Cyanobacteria to Grazing by Large-Bodied Daphnia in a Biomanipulation Scenario

摘要: Lake restoration practices based on reducing fish predation and promoting the dominance of large-bodied Daphnia grazers (i.e., biomanipulation) have been focus much debate due to inconsistent success in suppressing harmful cyanobacterial blooms. While most studies explored effects growth at community level and/or few dominant species, predictions such demand further understanding taxa-specific responses diverse communities. In order address these questions, we conducted three grazing experiments during summer a eutrophic lake where natural phytoplankton was exposed an increasing gradient biomass magna. This allowed evaluating cyanobacteria throughout growing season desired biomanipulation scenario with limited predation. Total biomasses responded negatively both early late summer, regardless different densities. Large-bodied were capable abundance Aphanizomenon, Dolichospermum, Microcystis Planktothrix bloom-forming cyanobacteria. However, filamentous Dolichospermum crassum positively affected by period when this cyanobacterium dominated community. The subjected since 2005 nineteen years monitoring data (1996-2014) revealed that increased mean (50%) body-size (20%) Daphnia, as well suppressed total amount nutrients taxa, Planktothrix. Altogether our results suggest solely grazer control can be effective, but may not sufficient overgrowth all diversity. Although controlling blooms should preferably include other measures, nutrient reductions, experimental assessment long-term highlights potential biomanipulations enhance ecological societal value water bodies.