SUMMARY AND CONCLUSIONS 



Overall, gravel removal from floodplalns frequently had a detrimental 

 long-term effect upon local terrestrial biota. Specific site locations 

 coupled with the depth of scraping proved to be the most influencing fac- 

 tors. 



VEGETATIVE REMOVAL 



At 18 of the 25 study sites gravel removal operations cleared signif- 

 icant quantities of riparian vegetated habitat. This loss most significantly 

 affected passerines and small mammals which rely upon these riparian zones 

 for primary feeding, nesting and cover habitats. At most of these sites this 

 habitat reduction led to long-term changes in fauna utilization and com- 

 mun i t y structure. 



At 4 of the 25 sites, gravel removal operations did not alter existing 

 vegetative communities, and consequently did not lead to changes in local 

 faunal communities. Three of these sites were located in floodplains with 

 large and medium width channels that flowed in a braided pattern. At all 

 three sites large quantities of gravel were removed by shal low scraping of 

 surface layers over a broad area. The fourth occurred on a sinuous to mean- 

 dering river. At this site a large quantity of gravel also was removed by 

 shallow scraping unvegetated portions of lateral bars and point bars. This 

 scraping maintained natural point bar profiles and subsequently did not 

 induce any channel changes. 



MINING DEPTH AND LOCATION 



Gravel removal operations that scraped to within or slightly below the 

 water table and that occurred at inside bends or immediately adjacent to, or 



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