Long-term forecast of thermal mortality with climate warming in amphipods from a temperate river

Abstract

Abstract: Forecasting the long-time consequences of global warming requires knowledge not just on thermal mortality but also how heat stress interacts with other environmental stressors1,2. Here we describe an analytical framework that combines laboratory measurements and high resolution field temperature records to forecast mortality risks over the next century. As a proof of concept, we study amphipods Dikerogammarus villosus and Echinogammarus trichiatus from river Waal, Netherlands, acclimated to different temperatures and oxygen levels. We predicted daily and annual heat mortality in the river under different oxygen levels for current temperatures and for 1 ºC and 2 ºC warming . Given the p rojected increases in summer temperatures, annual mortality is forecasted to increase substantially during the next decades, varying with acclimation status and water oxygenation. Both acclimation to elevated water temperatures and adequate oxygenation are crucial for persistence under current temperatures. However, even in the best case scenario, mortality in D. villosus is expected to approach 100 % by 2100, while E. trichiatus appears to be less vulnerable. Overall, this framework generates forecasts in unprecedented detail on short- and long-term temporal impacts of rising temperatures in ecological communities, and also the contribution of other environmental stressors.