resource managers may wish to exercise other options. Any site character- 

 istics or methods that facilitated rapid recovery to pred i sturbance con- 

 ditions were considered for implementation as guidelines. 



The presupposition that all changes due to gravel removal are undesir- 

 able does not, by necessity, cause the data analyses and recommendations 

 to be impractical. It is a foregone conclusion that changes will occur 

 when gravel is removed from a floodplain. To note that changes from the 

 natural state were less at one site than another suggests that the former 

 site was operated more consistently with characteristics of the system 

 than the latter, thereby reducing the magnitude of change. The floodplain 

 and gravel removal characteristics at sites that produced these minor 

 changes formed the primary basis for development of constructive guidelines 

 to minimize change. Conversely, the floodplain and gravel removal character- 

 istics at sites with major changes supported development of guidelines 

 primarily of a precautionary nature. 



The analyses in succeeding chapters treat the changes that were meas- 

 ured at individual study sites. There are sites, for example, where species 

 diversity increased as a result of site disturbance. In some contexts, 

 this increased diversity would be considered a beneficial effect of gravel 

 removal. However, in the context of this project, this effect initially was 

 evaluated equal to one which caused an equivalent decrease in species diver- 

 sity because it reflected a change from the naturally evolved condition. 



This project treats al I changes consistently and objectively as a 

 change from the natural, and special interest perspectives are neither 

 recommended nor encouraged. However, it is recognized that a resource man- 

 ager in certain circumstances may be greatly influenced by the need to 

 consider a site from a multiple or optimal use standpoint. For example, 

 subsequent to gravel removal a deeply dug site might be considered as a 

 water source in areas where winter supplies of water are minimal. Several 

 study sites were deep pits that contained water throughout the year. For- 

 mation of a pit represents a major change from the natural situation and the 

 site will not revert back to a natural situation for many years, if at all. 



