The aquatic organisms in braided systems are adapted to the seasonal 

 dynamics of the channels and, therefore, any channel changes resulting from 

 gravel removal operations provide situations for which the organisms are 

 already adapted. An exception to this generalization occurs where a pit is 

 separated from the active channel (Tanana River-Downstream) or is within the 

 floodplain (Dietrich R i ver-Upstream) and connected to an active channel. In 

 these cases, organisms that are more adapted to lentic environments become 

 established. Also, certain fish species may use the calmer waters of these 

 pits for spawning, rearing, and feeding areas. These pit sites are the excep- 

 tion, because scraping is the usual procedure selected to excavate sites in 

 braided systems. Excavating aspects are discussed further in the following 

 section on Types of Gravel Removal. 



Terrestrial species that utilize braided river systems similarly are 

 little affected by the usual scraping operation. Since non-vegetated bars 

 are favored gravel removal sites, few sma I I mammals or passerines are af- 

 fected. The water-associated birds that use the various channels and back- 

 waters for feeding are also little affected by the material sites because 

 the usual result of these operations is to provide habitats already present. 



Due to the dependence of sma I I mammals and passerines on vegetated 

 islands, gravel bars, and banks present in braided systems, any removal of 

 vegetation to expose a gravel deposit would total ly displace birds and 

 eliminate small mammals from the disturbed site. Similarly, these areas, 

 which often have associated dense shrub thickets, are used by moose and 

 ptarmigan, especially during winter. Loss of this habitat would cause lo- 

 calized displacement of these animals. 



Maintenance of the scenic quality of an area can be achieved by de- 

 signing a material site to complement the natural setting. Material sites in 

 braided systems did not detract from the visual quality of the floodplain 

 where gravel removal was restricted to unvegetated gravel bars. The ex- 

 pansive floodplains typical of these systems are somewhat uniform in ap- 

 pearance, yet the numerous channels and gravel bars endow these areas with a 

 complexity that permits material sites to be located with little effect. 



336 



