Authors: Altanov, Vassil; He, Fengzhi ;Bremerich, Vanessa ;Jähnig, Sonja;

Hydropower has been developed globally, supposedly providing reliably renewable energy, increase water supply, and help with flood control. However, the impacts of hydropower dams on freshwater biodiversity have been widely documented. Most existing studies have focused on the impacts on migratory fish such as the sturgeons and salmonids, with less attention being paid to semi-aquatic species including crocodilians, turtles, and mammals which are also susceptible to hydropower development, for example, through the impairment of their breeding and feeding habitats. We conducted a systematic literature review and synthesized the effects of hydropower dams on 61 semi-aquatic megafauna species (i.e., animals that depend on both freshwater and terrestrial habitats and can reach a body mass of 30 kg). We found that the impacts of hydropower dams vary among taxonomic groups and regions. By combining the data extracted from identified studies with global distribution data of semi-aquatic megafauna and hydropower dams (i.e., existing and proposed dams), our study highlights the gaps in current assessments and emphasizes the regions of priority for monitoring and conservation actions in the future. It provides insights into the development of effective strategies that may support balancing biodiversity conservation with hydropower development.