are 29 species of large aquatic vegetation located in the Old
Ausable River Channel. Six
of these species dominate certain sections of the river. The six species include: Chara vulgaris, Elodea canadensis,
Myriophyllum spicatum, Vallisneria americana, Wolffia spp. and Lemna
Wiklund (2001) showed that there are differences in aquatic vegetation above
and below the dam in the Pinery.
Chara vulgaris meadow
Looking down upon a stand
|Above the dam, the dominant species is
a plant species that creates a dense mat on the bottom of the river. This species is present due to the low turbidity and
bicarbonate rich groundwater that feeds the system in this section
of the river.
sp and Lemna minor
bloom covering water surface
the dam, closest to Grand Bend two species, Wolfia spp. and
Lemna minor become very abundant later in summer and cover the
water surface (looks like algae bloom on surface).
photos © Johan Wiklund
the dam in the Pinery, the turbidity of the water in the channel
increases. As well, the water conditions in this section of the channel
are heavily influenced by the Ausable River Cut. The water from the “Cut” is higher in nutrients primarily
because of inputs from agricultural land base.
Therefore, we observe two plant species that thrive under
seen up close growing in shallow water
|Elodea canadensis is dominant where
sediments are rich in nutrients.
forming a floating canopy
|Myriophyllum spicatum becomes abundant where sediments have low to moderate ammonium
|Vallisneria americana dominates near the confluence
with the Ausable River Cut due to the increased velocity and
turbidity of the water in this area.
research on the sediments of the Old Ausable River Channel concluded
that the centre of the channel is filling in with sediment. This is expected due to the slow flowing nature of the
present channel. When
there is no flow to carry the particles, they fall out of suspension
and settle at the bottom of the river.