Bivalve mortality and burrowing behavior under compound stress of salinity and temperature: Data from a mesocosm experiment

The frequency of extreme weather events, such as heatwaves and flash
floods, is increasing due to global climate change. While many studies
have investigated the potential impact of high temperature and salinity
fluctuations on benthic animals in tidal flats, few have explored how
these stressors affect the relationship between native and introduced
species, including the potential establishment of introduced species in
response to extreme short-term events. This study investigates the
compound effects of heatwaves and salinity changes on the survival and
burrowing behaviors of native and introduced bivalve species.
Specifically, the introduced species Ruditapes philippinarum and the
native species Cerastoderma edule were cultivated in four salinity
settings under five temperature blocks using a mesocosm experiment. The
results show that R. philippinarum exhibits lower mortality than C. edule
under temperatures exceeding 35 °C, especially those in lower salinity
levels of 10 and 20 PSU. Interestingly, the burrowing behaviors of the two
species did not differ significantly, indicating that they share similar
ecological functions under future climate change. However, if heatwaves
coincide with other stressors, like strong freshwater inputs, as shown in
this study, a potential widening of the establishment window for
introduced species may occur in future climate change scenarios. These
findings provide valuable insights into how compound extreme weather
events may drive species shift on tidal flats, with important implications
for understanding population dynamics under future climate change.