Future large hydropower dams impact global freshwater megafauna

Christiane Zarfl,Klement Tockner,Jürgen Berlekamp,William Darwall,Fengzhi He,Sonja C Jähnig

doi:10.1038/s41598-019-54980-8

Abstract

Dam construction comes with severe social, economic and ecological impacts. From an ecological point of view, habitat types are altered and biodiversity is lost. Thus, to identify areas that deserve major attention for conservation, existing and planned locations for (hydropower) dams were overlapped, at global extent, with the contemporary distribution of freshwater megafauna species with consideration of their respective threat status. Hydropower development will disproportionately impact areas of high freshwater megafauna richness in South America, South and East Asia, and the Balkan region. Sub-catchments with a high share of threatened species are considered to be most vulnerable; these are located in Central America, Southeast Asia and in the regions of the Black and Caspian Sea. Based on this approach, planned dam locations are classified according to their potential impact on freshwater megafauna species at different spatial scales, attention to potential conflicts between climate mitigation and biodiversity conservation are highlighted, and priorities for freshwater management are recommended.

Highlights

Dam construction comes with severe social, economic and ecological impacts
This study focuses on three main research questions: (1) To what extent may future hydropower dams affect the distribution ranges of freshwater megafauna on the global scale? (2) In which river basins will the threat to megafauna species by future dams be greatest? (3) Will those sub-catchments supporting the highest species richness and share of threatened megafauna species be disproportionately affected by future hydropower construction? The results of these analyses will highlight any potential conflicts between climate mitigation and biodiversity conservation, and help set priorities for future management of freshwater ecosystems
This can be attributed to the large hydropower potential still available in emerging economies to support industry and development, while much of the respective and accessible hydropower potential is already exploited in industrialized countries[24]

Summary

Introduction

Dam construction comes with severe social, economic and ecological impacts. From an ecological point of view, habitat types are altered and biodiversity is lost. Hydropower development will disproportionately impact areas of high freshwater megafauna richness in South America, South and East Asia, and the Balkan region. Dam construction is an established technology to generate hydropower, which is a renewable albeit not climate-neutral electricity source: Currently, 22% of the world’s electricity is provided by renewable resources, 73% of which by hydropower[1]. The global boom in hydropower dam construction will mainly take place in South America (Amazon and La Plata River basins) and in South and East Asia (Ganges-Brahmaputra and Yangtze basins) as well as in Africa, which will be experiencing a strong relative increase due to its high remaining technical hydropower potential. Since hydropower reservoirs can be used to store energy and generate it when required, the increase in hydropower capacity can, at the same time, support the expansion of further renewable energy technologies when installed in combination with hydropower. The expansion of hydropower is considered a potential solution to multiple challenges

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Conclusion