 Of the 3 @,@ 000 to 4 @,@ 000 remaining critically endangered Siberian crane , a large number currently spend the winter in wetlands that will be destroyed by the Three Gorges Dam . The dam contributed to the functional extinction of the baiji Yangtze river dolphin . Though it was close to this level even at the start of construction , the dam further decreased its habitat and increased ship travel , which are among the factors causing what will be its ultimate demise . In addition , populations of the Yangtze sturgeon are guaranteed to be " negatively affected " by the dam . 
