In 1990, vegetation distribution and abundance were studied along
five belt transects in Pool 13 of the Upper Mississippi River as
part of the Long Term Resource Monitoring Program, with 162
individual site plots sampled on five transects. Using
quantitative sampling techniques, 72 plant species were
identified. Floodplain forest communities exhibited the highest
species diversity, with 61 species represented. Shallow open
water communities exhibited the lowest species diversity, with
three species represented. Species richness in aquatic habitats
was significantly less than in terrestrial habitats. Of the 72
taxa cataloged in 1990 sampling, Acer saccharinum, Vitis riparia,
Toxicodendron radicans, and Laportea canadensis were the dominant
tree, shrub, vine, and ground layer species in floodplain forest
communities. Cephalanthus occidentalis and Leersia oryzoides were
the dominant shrub and ground layer species in wet meadow
communities. In shallow marsh communities, Sagittaria latifolia,
Nelumbo lutea, and Lemna minor were the dominant emergent, rooted
floating, and non-rooted floating species present. Nelumbo lutea,
Ceratophyllum demersum, Lemna minor, and Wolffia columbiana were
the dominant emergent, submergent, and floating species in deep
marsh communities. In shallow open water communities, non-rooted
Myriophyllum spicatum, Ceratophyllum demersum, and Lemna minor
were the dominant submergent and non-rooted floating species. A
large number of floodplain forest communities was observed in the
upper pool. This number was greatly reduced in the lower pool,
where open water communities prevail. The highest species
richness was observed in the Running Slough transect, which was
characterized by many habitats such as narrow islands and sloughs.
The lowest numbers of both terrestrial and aquatic species were
observed on transects in the lower pool, which consisted primarily
of large expanses of open water.
