Aquatic vegetation of the Upper Mississippi River System is monitored as part of the
Long Term Resource Monitoring Program. This report summarizes the 1993 effort of
monitoring submersed aquatic vegetation (SAV) along permanently established transects
in vegetated locations within certain LTRMP study reaches, specifically Pools 4, 8, 13,
and 26 of the Upper Mississippi River and La Grange Pool of the Illinois River. Data are
collected during two sampling windows, mid-May through mid-June, and mid-July
through August. Fifteen species of SAV were found along transects during the 1993
season. The greatest number of species found (12) was in Pool 4 and the fewest number
found (2) was in Pool 26. Coon's tail and sago pondweed were the only species found in
every study pool during both spring and summer sampling. In all study reaches except
La Grange Pool, the frequency of several species of SAV changed between sampling
periods, with decreases especially common among several species of pondweeds. Several
other species also decreased in Pools 13 and 26 between sampling periods. Conversely,
several species increased in frequencies in Pool 8 between periods. The proportion of
sites containing SAV declined during the season in Pools 4, 13, and 26, but not in Pool 8
or La Grange Pool.
