FIVE YEARS OF MACROINVERTEBRATE SAMPLING ON THE UPPER
MISSISSIPPI RIVER

Jennifer S. Sauer, Environmental Management Technical Center, 575 Lester
Avenue, Onalaska, WI  54650

The temporal variability in mayflies (Ephemeridae), fingernail clams
(Sphaeriidae), and midges (Chironomidae) in six study reaches of the Upper
Mississippi River System was examined.  Spatial distribution also is discussed for
these organisms along with the Asiatic clam, Corbicula fluminea, and the zebra
mussel (Dreissena polymorpha).  Sample allocation was based on a stratified
random design which was based on aquatic area.  No significant linear trends
across years were determined in estimated mean number of organisms.  However,
the overall test for differences in intercepts among study reaches was statistically
significant (P<0.05) for mayflies, fingernail clams, and midges.  Overall, the
impounded aquatic areas and silt/clay substrates tended to support higher numbers
of the select macroinvertebrates. 

Key words: Mississippi River, mayflies, Ephemeroptera, fingernail clams,
Sphaeriidae,             Chironomidae


Jennifer S. Sauer
Environmental Management Technical Center
575 Lester Avenue
Onalaska, WI  54650
608-783-7550 ext. 64
Fax 608-783-8058
jennie_sauer@nbs.gov

POSTER (Willing to convert to platform)