4 Species Impacted by Dams

Free-flowing rivers are the freshwater equivalent of wilderness areas. They’re home to a diverse array of species, and provide food and water for animals and people.

Many freshwater species depend on free-flowing rivers to complete their life cycles and, in some systems, those species make up critical parts of people’s diets. WWF wants to protect these rivers—and the species and people that depend on them—by helping governments and communities make smart decisions about infrastructure.

We promote sustainable dam projects in certain areas, and encourage an understanding of all the positive and negative impacts of specific dams before their construction and operation.

Here’s a look at four important species impacted by dams.

Judy Takats, Senior Program Officer, WWF, helps release a sturgeon into the wild.

1. Sturgeon
Dams divide rivers, creating upstream and downstream habitats. But migratory fish, such as sturgeon, depend on the whole river. Dams block their ability to travel back upstream. Sturgeon also rely on temperature triggers and shallow areas for reproduction. Because dams change how rivers flow, the water temperature and natural conditions also change. This prevents sturgeon from mating and/or hinders the development of fish larval.


2. Egrets
Egrets, along with other wetland birds, depend on healthy river systems for food and shelter. They make their nests in the steep banks of rivers or floodplain thickets. Dams prevent the natural highs and lows of rivers They can also reduce the breeding ground of migratory fish—a key food source for egrets—and cloud the waters, making it harder for egrets to spot their prey.


3. Irrawaddy Dolphins
All river dolphins need freshwater fish, quality water and safe migratory routes to survive. Poorly planned dams often reduce dolphins’ food supply, change water quality and destroy habitats. As dams are constructed, the dynamite and noise can harm river dolphins. Once the dam is up, increased boat traffic can lead to more injuries and deaths from collisions.


4. People
Just like all the previously listed animals affected by dams, we depend on natural river flows to purify water, fuel floodplain forests, and nurture fish. While we also depend on dams for hydropower, we need to ensure dams are necessary, properly located, and outfitted to have as minimal impact on the environment as possible.