Figure 4.8 



Status of Wetlands in the United States 



Alaska 



Wetlands facing greatest ttireat of drainage y^^Q Waterfowl wintering tiabitat needing protection ^ Destroyed by fiigtiway construction 



and water facilities 

 Waterfowl breeding fiabitat needing protection A Urban or industrial encroactiment 



States resulted when the price of wheat accelerated 

 after large sales to the Communist bloc nations in the 

 early 1970's. 



Riparian habitats on rangelands are very suscepti- 

 ble to damage from overgrazing by livestock. Re- 

 moval of tree cover in the understory is of special 

 concern, particularly in the Southwest where this rel- 

 atively limited habitat is vital to the native fauna. Its 

 removal reduces wildlife population levels and uUi- 

 mately the variety of wildlife that can be supported. 

 When riparian lands are grazed too heavily, stream- 

 banks are damaged, movement of sediment into the 

 stream channel is accelerated, stream channels tend 

 to become wider and shallower, and the water 

 becomes warmer. These physical changes may adver- 

 sely affect aquatic organisms. To some degree, down- 

 stream habitats are also affected. 



Modifications of Aquatic Ecosystems 



The relative importance of current water-related 

 activities and conditions that have major implications 

 for wildlife and fish is shown by section in table 4.18. 



The problems of major concern include reductions in 

 streamflows, physical changes to free-flowing streams 

 and rivers, pollution, and sedimentation. 3"* 



The consumptive use of water for urban, agricul- 

 tural, and industrial purposes and the consequent 

 reductions in streamflows is great enough in some 

 areas to threaten the existence of aquatic organisms. 

 This is particularly true in the Southwest and in the 

 southern portions of the Rocky Mountains and Great 

 Plains. In especially dry years, problems also com- 

 monly occur in central California, as far north in the 

 Great Plains as Kansas, and in the south central por- 

 tion of Oregon and in southern Florida. ^^ 



^■•This discussion is primarily drawn from U.S. Water Resource 

 Council. The Nation's water resources — Part III, functional water 

 uses, Chapter 10: water requirements for fish and wildlife and 

 related instream flows (review draft), p. 232-270. 1978. 



'5 An inference from the Supreme Court decision in the Rio 

 Mimbres case of 1978 is that the Forest Service has no legal right 

 to divert water solely for wildlife or fishery purposes in the western 

 States; the applicability to other Federal land-managing agencies 

 has not yet been tested. See Wengert, N. Reserved rights and Fed- 

 eral claims to waters. In Proc, Legal, institutional, and social 

 aspects of irrigation and drainage and water resources planning 

 and management. Amer. Soc. Civil Engineers. (NYC), p. 93-107. 

 1979. 



137 



