The Long Term Resource Monitoring Program conducted monitoring of submersed
aquatic vegetation in Pool 8 of the Upper Mississippi River System in 1995. A rapid
assessment technique was used to sample 45 transects in eight backwaters during two
sampling windows (spring and summer). Sixteen species from 10 families were recorded.
The number of species increased from spring (13) to summer (15). Zannichellia palustris
L. was found only during the spring sampling period, while Vallisneria americana L.,
Heteranthera dubia (Jacq.) MacM., and Najas flexilis (Willd.) Rostk. & Schmidt were
found only in summer. Lawrence Lake had the most species (15), and the Boomerang
Island area had the least (6). Frequency of vegetated sites increased from spring to
summer in Pool 8. The two isolated backwater areas had the highest percentage of
submersed, vegetated sites. The most frequently recorded submersed species during
transect sampling were Ceratophyllum demersum L. and Potamogeton pectinatus L. An
informal survey of Pool 8 was conducted between the two transect sampling windows.
Two hundred forty-three submersed plant beds were located. One species, Myriophyllum
sibiricum Komarov, was found only during the informal survey in an isolated backwater
area. Potamogeton pectinatus and P. nodosus Poir. were the most frequently recorded
species.
