Multibiomarker response shows how native and non‐native freshwater bivalves differentially cope with heat‐wave events

Abstract

Abstract Temperature has a key impact on the physiology, food acquisition, metabolic rate, growth, and reproduction of organisms. Thus, exploring the effects of climate change on species physiology is important for the conservation and management of native and non‐native bivalve species. In this work, an integrative laboratory approach was used to compare the physiological, cellular, and molecular responses of the native Unio delphinus and the invasive non‐native Corbicula fluminea under a natural heat‐wave event. Whereas the filtration rate in C. fluminea was clearly affected throughout the whole heat‐wave event (from the heat peak onwards), it was only significantly affected during the heat‐wave climax in U. delphinus, and recovered afterwards. At the cellular level, lysosomal membrane stability was affected during the heat‐wave climax, but recovered afterwards, in both native and non‐native bivalve species. At the molecular level, hsp70 and hsp90 gene expression were increased and decreased (respectively) in C. fluminea after the heat wave. In contrast, only hsp90 gene expression decreased in U. delphinus during the climax and after the heat wave. The present work demonstrates that accurate monitoring of native and non‐native species using an integrated biomarker approach provides new insights into how both species might cope with the expected increase in frequency and intensity of heat events in a global warming context. Direct and indirect impacts of heat waves have been associated with massive mortalities of both native and non‐native species. Despite present results showing that C. fluminea are more sensitive to heat waves than U. delphinus, massive mortality events might act in favour of C. fluminea as it has a higher reproductive capacity. Although native freshwater mussel species conservation is already threatened by overexploitation, flow regulation and diversions, habitat destruction, and pollution, it is probably also adversely affected by global warming and the presence of invasive non‐native species, such as C. fluminea.