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for adults prior to spawning, preferred rearing areas for 

 juveniles, and refuges from drought or winter freeze-up. While 

 the quality of spawning and rearing habitat on managed lands has 

 diminished, anadromous fish habitat in wilderness areas remained 

 relatively constant or improved during the same time period. 



The most important of the activities which affect fish habitat 

 are: 



Timber harvest and road construction - These activities can cause 

 loss of riparian zone vegetation, change stream temperatures and 

 light regimes, cause loss of rearing cover due to a loss of large 

 woody debris, reduce oxygen levels, alter stream flows and 

 increase fine sediments in the channels. Sedimentation can lead 

 to a loss of large pools (rearing habitat) and degradation of 

 spawning habitat, resulting in reduced survival of eggs and fry. 

 Improperly designed stream road crossings may limit access, 

 resulting in the elimination of tributary habitat. 



Livestock grazing - This activity may damage riparian habitats 

 and has the potential to reduce anadromous fish production 

 through stream bank instability and accelerated sediment 

 production. Cattle trailing across spawning riffles may cause 

 direct mortality of incubating eggs and alevins in the redd. 

 Studies comparing grazed and ungrazed watersheds have shown that 



