EFFECTS OF FLUCTUATING FLOW RATES 



151 



5000 



3000 



Z 

 Q 



1000 



> 



CO 



z 



Q 



MAR. MAY JUNE JULY 

 MONTH 



(a) 



MAR. MAY JUNE JULY 

 MONTH 



(b) 



Fig. 7 Density values for stations C-1 (a) and C-2 (b), based on 

 averages of triplicate samples, except for use of duplicates in March. 



G-3; June at C-2, P-2, and G-2; July at C-1 and P-1; and August at 

 G-1. Thus the station with relatively slower and more uniform flow 

 had earlier peak densities. 



Chironomid diversity (d) was relatively low throughout the 

 sampling period; values ranged from 0.34 to 2.67. Only at station 

 G-1 did diversity remain relatively uniform, but these values were 

 strongly influenced by the relatively low densities of chironomids 

 collected at this station. 



The patterns of generic distributions resemble those of chiron- 

 omid density. The exposed Grand River sites generally contained 

 fewer taxa (G-1 and G-3 both had only 14 genera) than did the more 

 protected station (G-2 had 16 genera) and most of the tributary 

 stations. The stations on Chouteau Creek had high generic 

 diversity, with the maximum number (21 genera) occurring at 

 C-2. Again, as for most values of density and biomass, the 

 numbers of taxa were lower at the upstream stations in both 

 Pryor and Chouteau creeks. 



DISCUSSION 



The high density of Glyptotendipes at most sampling stations is 

 not surprising when we consider the ecological distribution of the 



