Abstract

Seventy-seven percent of the total water discharge of the 139 largest river systems in North America north of Mexico, in Europe, and in the republics of the former Soviet Union is strongly or moderately affected by fragmentation of the river channels by dams and by water regulation resulting from reservoir operation, interbasin diversion, and irrigation. The remaining free-flowing large river systems are relatively small and nearly all situated in the far north, as are the 59 medium-sized river systems of Norway, Sweden, Finland, and Denmark. These conditions indicate that many types of river ecosystems have been lost and that the populations of many riverine species have become highly fragmented. To improve the conservation of biodiversity and the sustainable use of biological resources, immediate action is called for to create an international preservation network of free-flowing river systems and to rehabilitate exploited rivers in areas that lack unaffected watercourses.

Keywords

BiodiversityInterbasin transferFragmentation (computing)Drainage basinGeographyStreamflowEcosystemEnvironmental scienceWater resourcesHydrology (agriculture)IrrigationEnvironmental protectionWater resource managementEcologyFisheryGeologyBiology

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Publication Info

Year
1994
Type
article
Volume
266
Issue
5186
Pages
753-762
Citations
1709
Access
Closed

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Mats Dynesius, Christer Nilsson (1994). Fragmentation and Flow Regulation of River Systems in the Northern Third of the World. Science , 266 (5186) , 753-762. https://doi.org/10.1126/science.266.5186.753

Identifiers

DOI
10.1126/science.266.5186.753