Habitat Loss & Alteration
- An estimated 60% of the world's river basins are affected
- There are around 50,000 large dams worldwide
- China, Brazil, Canada and the USA make up about 50% of the world's hydropower
Agricultural practices, infrastructure development—in particular construction of dams and reservoirs (see our work with FFI)—and urbanisation have led to the rapid reduction and alteration of freshwater habitats.
Dams and reservoirs in particular dramatically change the structure and function of freshwater ecosystems changing the water flows, temperature and sedimentation processes. This poses serious challenges to habitats, leading to the reduction of species diversity and changes in migratory behaviour and spawning patterns. Dams alone have an estimated 10,000 cubic kilometers of water trapped behind them—five times the volume of all the world’s rivers. In the Northern Hemisphere, the proliferation of dams has even led to changes in the Earth’s gravitational field.