756 



BECKETT 



5 6 7 8 

 STATIONS 



Fig. 3 Total number of macroinvertebrate taxa (S/station) for June 

 (O), August (A), and September (n) 1976 collection dates, Great 

 Miami River system, Ohio. 



downstream stations did not show recovery to Tait power-plant 

 intake S levels. 



Modifications of the Great Miami's flow (modifications made in 

 the early 1920s for flood-control purposes) and the river's passage 

 through Dayton did not preclude relatively high levels of diversity or 

 species richness below Dayton. The community at the intake of the 

 Tait power plant, located approximately 6 km below the downtoAvn 

 area, had diversity values above 3.0 for all three sampling periods. 

 This station consistently supported the highest or near highest 

 number of macroinvertebrate taxa. Higher diversity and total taxa 

 values at station 4 (in comparison to stations 1 to 3) may be partially 

 due to an increase of stream order (Hynes, 1970; Harrell and Dorris, 

 1968) with the confluence of the Mad, Stillwater, and Miami rivers. 

 Biotic compositional changes due to longitudinal zonation along my 

 study area were not apparent, however. The CC index values between 

 stations 3 and 4 were quite high in both June (0.72) and September 

 (0.78). No increase in stream order occurred in the remainder of the 

 study area (stations 4 to 14). 



