indices, and Shannon-Weaver and Simpson density indices. The indices respond 

 differently to changes in density and diversity and were used primarily to 

 search for changes in the aquatic macro i nvertebrate assemblages vulnerable 

 to Surber samplers. 



Because the level of identification was to the generic level at best 

 and often only to family or order, the indices were applicable only to the 

 present study. Comparison with results of other studies and extensive anal- 

 ysis of the data are not justified. Often multiple species within a genus 

 were recognizable but the absence of suitable taxonomic aids for arctic 

 aquatic macro i nvertebrates inhibited identification. A list of collected 

 taxonomic groups by phyletic classification, with associated common names, 

 is included in Appendix A. 



147 



