The creation of the Three Gorges Dam has lead to the endangerment and extinction of many plant and animals. The Three Gorges region is considered a biodiversity hotspot. It is home to over 6,400 plant species, 3,400 insect species, 300 fish species, and more than 500 terrestrial vertebrate species. The disruption of the river’s natural flow dynamics due to blockage will affect the migratory paths of fish. Due to the increase of ocean vessels in the river channel, physical injuries such as collisions and noise disturbances have greatly accelerated the demise of local aquatic animals. The Chinese river dolphin which is native to the Yangtze River, and the Yangtze finless porpoise have now become two of the most endangered cetaceans in the world.
The hydrological alternations also affect fauna and flora downstream. Sediment build-up in the reservoir has altered or destroyed floodplains, river deltas, ocean estuaries, beaches, and wetlands, which provide habitation for spawning animals. Other industrial processes, such as the release of toxic substances into the water also compromise the biodiversity of the region. Because the water flow is slowed due to the reservoir impoundment, the pollution will not be diluted and flushed to the sea in the same manner as before the damming. Additionally, by filling the reservoir, thousands of factories, mines, hospitals, garbage dumping sites and graveyards have been flooded. These facilities can subsequently release certain toxins such as arsenic, sulfides, cyanides, and mercury into the water system.
It should be no surprise that the river system downstream has also been affected. A decrease in freshwater flow has meant that more saltwater is creeping up the Yangtze, endangering fish populations already threatened by overfishing.
Dams block access to tributaries and lakes where certain animals once caught food and where some created a place to live.
Major changes in fish