How will climate change affect global amphipod species distributions by the end of the century?

The concern about how climate change affects marine ecosystems is growing, despite the international commitment to reduce the rate of CO2 emissions. Predicting amphipod species responses to ocean warming is critical due to their high abundance and key ecological role in marine ecosystems. We applied Maximum Entropy (MaxEnt) modelling on 17 selected benthic amphipod species across different ocean depths and feeding groups to evaluate their response to different future climate change scenarios. We used SSP 2.6 (low CO2 emission scenario) and SSP 8.5 scenarios (high CO2 emission scenario) on a global scale projected to the years 2050 and 2100. We further employed linear mixed-effects models (LMMs) to reveal differences in feeding groups’ responses across different scenarios and time scales. The projected distributions exhibited the reshaping of amphipod species composition areas, including potential local extinctions and the possibility of invasions into new locations. Multiple environmental variables contributed to the model outputs predicting future distributions across different feeding groups. Chlorophyll concentration and turbidity contributed majorly in predicting the future distribution of deposit feeders, while temperature and O2 were more influential for suspension feeders and herbivorous amphipods. Our findings indicated that trophic ecology mediates climate sensitivity, as a significant interaction between feeding types and two scenarios was observed. These findings highlight that climate change may dramatically alter the functional composition of benthic communities and their ecological roles, beyond simple changes in species distributions, emphasizing the need to consider ecological roles and trophic identity when assessing climate impacts on marine ecosystems.