Ecological impacts of invasive bivalves feeding: influence of hydrological fluctuations and anthropic stressors.

Abstract

Invasive bivalves are among the most detrimental organisms to aquatic environments. Limnoperna fortunei (Dunker, 1857) and Corbicula fluminea (Müller, 1774) are two Asian-origin species whose filtration activity significantly alters ecosystem structure and functioning. Despite their prevalence worldwide, important literature knowledge gaps remain regarding the trophic dynamics of L. fortunei in floodplain systems, as well as the role of climate-related stressors in modulating the ecological impacts of C. fluminea on phytoplankton communities. Therefore, the objective of this work was to identify the resources assimilated by L. fortunei using stable isotopes analysis across floodplain systems with varying degrees of human influence (Paraná and Baía rivers) and during different hydrological phases (drought, rising water, and flood), and to evaluate, using an experiment, how anthropogenic eutrophication and CO₂-induced acidification influence the filtration impacts of C. fluminea on phytoplankton density, richness, community composition, and temporal beta diversity. Both bivalves showed high trophic and environmental plasticity. L. fortunei used different resources between rivers and throughout the hydrological cycle, replacing resources according to their abundance. C. fluminea reduced phytoplankton density and led the community to a dominance of taxa resistant to filtration, despite differences in trophic status and CO2 acidification. Between the stressors, CO2 acidification was the main factor responsible for changes in the composition of the phytoplankton community. Understanding the ecological niche of L. fortunei under contrasting hydrological and anthropogenic conditions, together with the impacts of C. fluminea under multiple stressors, is essential for anticipating ecosystem changes and managing ecosystems to preserve biodiversity.