Ecological research on hydropower impacts in lakes is falling behind that in rivers

Hydropower is expected to play an important role in future energy systems by helping balance variable wind and solar energy production. While hydropower impacts on river ecosystems have been extensively studied, far less attention has been given to lakes. It remains unclear whether the current knowledge base is sufficient to enable biodiversity conservation. We performed a bibliometric study comparing lake- and river-focused research to assess existing knowledge of the ecological effects of hydropower on lakes and the relative maturity of lake-focused research. We conducted a structured literature search on “freshwater ecology and hydropower” using two bibliographic databases. Studies were classified as lake ( n = 929) or river ( n = 7210) studies. Article co-citation analysis showed limited overlap in foundational literature (18%), suggesting limited knowledge transfer between fields. Recent river studies (2019–2024) more frequently used approaches such as meta-analysis, eco-engineering, and optimization, whereas lake studies more commonly consisted of smaller-scale observational or experimental studies. Our results revealed clear differences in scientific structure between lake- and river-focused research, consistent with a lower level of scientific maturity in lake-focused research. Existing knowledge gaps may limit opportunities for conserving lake ecosystems, including the development and implementation of effective mitigation measures.