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  • Print publication year: 2020
  • Online publication date: June 2020

7 - How Will Climate Change Affect Freshwater Biodiversity?

Summary

Flow regulation and water abstraction from rivers have devastating effects on receiving lakes. The most egregious example is the Aral ‘Sea’: from the 1960s, water for irrigation was diverted from influent rivers; 40 years later, the Aral had dwindled to tiny remnants - fisheries had long since collapsed. Shrinkage of lakes and wetlands across central Asia demonstrate the consequences of expanding irrigation, and highlight conflicts among human water users. Lake Chad in Africa has virtually disappeared as a result of water mismanagement, as has Lake Poopó in Bolivia; Yangtze floodplain lakes have diminished also. All such cases have had serious consequences for migratory waterbirds. In a few instances (Mono Lake in the US, the Mesopotamian marshes), the damage caused can be partially reversed by restoring water supplies, but the causes and drivers of ecosystem degradation are particular to each lake. Even the world’s largest water body, Lake Baikal, is subject to anthropogenic insult. Here, as is typical of lakes globally, a variety of factors – most often eutrophication, land-use change and alien species – contribute to habitat degradation and declines of endemic species.