In general. Group I parameters either stiowed no response, or displayed 

 a significant decrease resulting from gravel removal induced changes. This 

 was directly related to clearing of significant quantities of vegetation 

 which passerines, moose, and ptarmigan used as primary habitat. 



Group II parameters displayed no response at sites where vegetative 

 habitats were not disturbed. However, all parameters except soil nutrients 

 decreased at sites that were subjected to permanent or frequent hydraulic 

 stresses (aufeis, ponding, and flooding) and did not contain overburden 

 piles. At sites that were subjected to hydraulic stress but which contained 

 overburden piles, small mammals, ground squirrels, and early shrubs increas- 

 ed. Soil nutrients basically displayed no response. 



Group III parameters either displayed no response at sites where the 

 floodplain character was not significantly disturbed, or they increased. 

 Both parameter responses were once again directly related to removal of 

 extensive vegetative cover. Water birds increased in response to the in- 

 crease in aquatic, gravel bar, and mud flat habitats, while soil texture 

 increased due to the removal of organic, silt, and sand overburdens and the 

 exposure and deposition of coarse gravels and cobbles. 



Physical Site Characteristics 



The Physical Site Characteristics that were analyzed are those identi- 

 fied in the Major Variable Matrix Table (Table I). They included: drainage 

 basin size, channel width, channel configuration, channel slope, and stream 

 or i g i n . 



Responses of biotic parameter groups at the 25 study sites displayed 

 five basic combinations. These are labeled Site Response Group A through E 

 on Table 34. Eight sites occurred in Group A, where no significant responses 

 were measured in any of the biotic parameter groups. These sites were mostly 

 of medium to large channel widths, of braided or sinuous configuration, and 

 of mountain or foothill origin. However, these site characteristics were not 

 considered to have significantly contributed to the minimal disturbance at 

 these sites. Of greatest significance was the minimal vegetative disturbance 

 which occurred during the gravel removal operations. 



26 1 



