Thermal tolerance and vulnerability to climate warming in the freshwater shrimp Atyaephyra desmarestii and Caridina multidentata.

Freshwater shrimp play crucial roles in aquatic ecosystems, yet their vulnerability to climate change remains poorly understood. This study investigates the thermal tolerance and vulnerability to climate warming of two important freshwater shrimp species with contrasting ecological preferences, Atyaephyra desmarestii and Caridina multidentata. Critical thermal maximum (CTMax) was assessed for different acclimation temperatures that cover the current summer range for both species, as well as for populations from different geographical origins for A. desmarestii. Both species demonstrated an excess of thermal tolerance in all conditions, as calculated with the thermal safety margins (TSM). However, the decrease of TSM with increasing acclimation temperatures suggested potential limitations in their ability to cope with future warming, particularly for the southern populations of A. desmarestii. Furthermore, while C. multidentata showed a high tolerance to extreme temperature fluctuations, it may face challenges in maintaining viable populations under projected climate change scenarios. The present study also provides a survey of the thermal limits of Caridea, thereby highlighting the necessity for further research on the thermal tolerance of shrimp to inform effective conservation strategies and mitigate the impacts of climate change.