AQUATIC VEGETATION COMMUNITIES OF POOL 13 OF THE UPPER MISSISSIPPI RIVER SYSTEM

Amy Waterman1, Theresa Blackburn2
1Environmental Science Program, University of Dubuque, Dubuque, IA 52001   2Iowa 
Department of Natural Resources, Long Term Resource Monitoring Program, 
Bellevue, IA 52031 

During the summer of 2001, a study was conducted on pool 13 of the Upper 
Mississippi River System to evaluate the aquatic plant diversity, and to 
correlate diversity with various parameters including Secchi disc transparency, 
substrate type, and amount of detritus.  This study focused on the composition 
of the plant community, utilizing methods employed by the Long Term Resource 
Monitoring Program.  There were five strata types that were sampled which varied 
in substrate type and current velocity: main channel border, side channel, 
impounded, backwater contiguous, and backwater isolated.  All strata types 
contained some aquatic plants.  As the current decreased, and the sites became 
more isolated, the percent of vegetated sites within a stratum increased.  
Substrates such as silt/clay and mostly silt with some sand contained the most 
diverse groups of plants.  Specifically mentioned in this study is Myriophyllum 
spicatum, otherwise commonly known as Eurasian watermilfoil.  This species was 
found in three of the five strata types.  As current diminished and Secchi disc 
transparency increased, plant diversity increased.  Each stratum had a unique 
plant community.

Keywords:  Mississippi River, aquatic vegetation, Eurasian watermilfoil, 
Myriophyllum spicatum, plant diversity