Future large hydropower dams impact global freshwater megafauna

Area of Science:

• Ecology
• Conservation Biology
• Environmental Science

Background:

• Dam construction significantly alters habitats and reduces biodiversity.
• Freshwater ecosystems face increasing pressure from human activities like hydropower development.

Purpose of the Study:

• To identify global areas of high conservation concern for freshwater megafauna impacted by existing and planned hydropower dams.
• To highlight potential conflicts between climate change mitigation goals and biodiversity conservation.

Main Methods:

• Overlaying global data on existing and planned hydropower dam locations with freshwater megafauna distribution.
• Incorporating species threat status to assess vulnerability of different sub-catchments.
• Classifying planned dam impacts on freshwater megafauna at various spatial scales.

Main Results:

• Hydropower development disproportionately threatens megafauna-rich regions in South America, South/East Asia, and the Balkans.
• Sub-catchments with high proportions of threatened species are most vulnerable, found in Central America, Southeast Asia, and near the Black/Caspian Seas.
• Planned dams pose significant risks to freshwater biodiversity, necessitating careful management.

Conclusions:

• Urgent conservation priorities for freshwater megafauna are identified in regions with high hydropower development potential.
• Balancing climate change mitigation with biodiversity conservation is crucial for sustainable freshwater management.
• Strategic planning is needed to minimize the ecological footprint of hydropower projects.