HOME ON THE BIG RIVER: ASSESSING HABITAT CONDITION IN THE GREAT RIVERS OF THE 
CENTRAL UNITED STATES

Debra L. Taylor, Theodore R. Angradi, David W. Bolgrien, Brian H. Hill, Terri M. 
Jicha, Mark S. Pearson, Sharon L. Batterman, and Mary F. Moffett

USEPA, ORD, NHEERL, Mid-Continent Ecology Division, 6201 Congdon Blvd., Duluth, 
MN 55804.

      The Great Rivers of the mid-North American continent represent significant 
wildlife habitat, and are important human recreational destinations and 
transportation corridors.  To assess the condition of the habitat along the 
mainstems of the Great Rivers of the central U.S., the EPA Environmental 
Monitoring and Assessment Program began sampling the Upper Mississippi, Missouri 
and Ohio Rivers in 2004.  Principal Components Analysis (PCA) was used to 
identify influential habitat variables. On the Mississippi River, PCA axis 1 
divided reaches with forested riparian zones from highly revetted sites with 
little riparian vegetation.  Axis 2 separated sites with varying amounts of 
large woody debris and other fish cover.  PCA axes 1 and 2 accounted for 43 
percent of the variation between sites on the Missouri River, with axis 1 again 
dividing well-vegetated from unvegetated riparian zones and axis 2 sorting 
reaches by degree of bank revetment, and by littoral slope and depth.  PCA axis 
1 on the Ohio river also separated sites by extent riparian vegetation while 
axis 2 divided sites with ample in-river woody debris from sites in heavily 
agricultural areas.  Data will be used to identify human-induced stressors and 
integrated into indices that express the habitat requirements of 
macroinvertebrate and fish communities.

Keywords:  Great River, habitat, revetment, riparian, woody debris