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Whitford, Philip; Whitford, Kathryn (ed.) / Transactions of the Wisconsin Academy of Sciences, Arts and Letters
volume 74 (1986)

Keough, Janet R.
The Mink River- a freshwater estuary,   pp. 1-11 PDF (4.8 MB)

Page 7

1986] Keough—Mink River Estuary 7 
sampled, and observations were made of submergent species (species are listed
in Table 1). Estimates of biomass were made using samples of above- and below-ground
material harvested in each community every month during the two growing seasons.
Peak biomass values from that period are presented in Table 2, and each community
is described below. 
Deep Marsh 
 The deep marsh complex occurs adjacent to channels of the Mink River. Several
species form this community type, but seldom do more than two or three occur
together. For example, Sparganium eurycarpum forms monotypic stands near
the river mouth and in patches on mud flats in "Rogers Lake." Occasionally,
a few individuals of Sagittaria latifolia are intermixed with Sparganium.
Zizania aquatica is found in monotypic stands on mudflats. 
Zizania populations fluctuate widely from year to year; dense populations
are found only during years when mudflats are exposed or near the water surface.
For example, in 1982, the level of Lake Michigan was 6 inches lower than
in 1981. Mud flats were exposed in Rogers Lake, and supported more numerous
and dense Zizania populations than the previous year. 
 Scirpus validus occurs over a wide range of water level conditions. This
species forms monotypic stands on shallow organic mudflats around Rogers
Lake. With Sagittaria latifolia, it forms two-species stands along the Mink
River channel. A tall form, probably a hybrid with S. acutus (Galen Smith,
pers. comm), grows with Eleocharis smallii around the edge of Rowley Bay.
Scirpus americanus also forms monotypic stands in deep water in the open
bay, where the populations are exposed to wind and waves. Typha angustifolia
also forms single species 
TABLE 2. Peak biomass of emergent herbaceous communities of the Mink River
estuary in 1981. 
Month of peak biomass occurrence is indicated. 
Community Type 
Above Ground g/m2 (month) 
Below Ground g/m2 (month) 
Areal Extent km2 
Deep Marsh 
Scirpus validus Community 
in Rowleys Bay 
595.4 (Aug) 
1373.6 (Aug) 
along Mink R. channel 
204.1 (Aug) 
268.6 (Sept) 
shallow marsh edge 
194.9 (Aug) 
336.6 (Sept) 
edge of Rogers Lake 
410.1 (Aug) 
493.6 (Sept) 
Sparganium eurycarpum Community 
at river mouth 
512.7 (Aug) 
704.0 (Sept) 
Rogers Lake islands 
628.2 (Aug) 
400.3 (Aug) 
Zizania aquatica Community 
Rogers Lake islands 
545.5 (Sept) 
207.7 (Sept) 
Typha angustifolia Community 
at river mouth 
880.6 (Aug) 
1626.4 (Sept) 
Shallow Marsh 
Carex aquatilis/C. prairea Community 
between headw. creeks 
327.1 (Aug) 
806.0 (Sept) 
Phragmites communis Community 
between headw. creeks 
686.1 (Sept) 
1867.6 (Sept) 
Wet Meadow 
Calamagrostis canadensis/Carex stricta Community 
along river 
779.7 (Sept) 
6486.8 (Sept) 

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