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LAKE POYGAN
CANE BED RESTORATION
Boaters,
anglers, snowmobilers, and waterfowl hunters using Lake Poygan
in the vicinity of the “West Bay Canes” cane beds (Figure 1)
during the next two years will see warning buoys and flashing
amber lights at the west end of these beds. These lights (which
flash only at night) and buoys warn of 54 partially submerged
concrete dunage blocks each measuring 2’x2’x6’. The blocks are
set in a curving line, 300 feet in length, adjacent to the cane
beds (Figure 2). The blocks are acting as temporary wave
barriers to protect a restoration project within the cane beds.
The blocks will be removed no later that October 1st,
2013.
Why restore the
cane beds?
Cane, or giant reed grass (scientific name Phragmites
australis), is a perennial grass typically found in very
shallow marshes. The cane beds on Lakes Butte des Morts,
Winneconne and Poygan (the upriver lakes of the Winnebago Pool)
are remnants of the vast marshes that existed on these lakes
before the construction of the Neenah and Menasha dams in the
1850’s. These cane beds provide a suitable environment for a
number of aquatic plant species that otherwise would not be
present in the open waters of these lakes. This is especially
true of the West Bay Canes. This plant diversity attracts a
diverse assemblage of desirable fish and wildlife, some of which
would not be found in the mostly open, featureless lake basins.
Twenty-nine species of fish, including walleye, northern pike,
largemouth bass, and panfish, have been recorded at the major
Lake Poygan cane beds. The West Bay Canes on Lake Poygan are
also home to Wisconsin’s largest nesting colony of the
endangered Forster’s tern. Cumulatively, offshore cane beds are
a significant component of the upriver lakes ecosystem. Most
anglers and waterfowl hunters are already aware of the value of
the cane beds.
Why are the
cane beds in trouble?
Analysis of aerial photos from 1937 to 1997 indicated
significant losses in area for some cane beds during this
period. Researchers have concluded that the pattern of decline
in offshore cane beds is likely due to a number of stresses, but
primarily to a seasonal pattern of water level management that
has remained largely unchanged over the last several decades.
The canes grew and thrived in water that was almost three feet
shallower than it is now; basically they are slowly drowning,
and have been for decades. Other stresses include wave and ice
attack, poor water clarity, carp, and even insects such as
aphids. Damage can also result from boating in or thru the cane
beds, especially during the growing season.
How is
restoration of the
West
Bay cane beds
being done? In
2004, the Lake Poygan Sportsmen’s Club acquired ownership of
almost 900 acres of the bottom of Lake Poygan from a private
hunting club. This acreage includes most of the West Bay
Canes. The Lake Poygan Sportsmen’s Club had previously funded
research, conducted by the University of Wisconsin-Oshkosh,
which concluded that significant water level manipulation (i.e.
lower water levels) and/or protection on the windward sides
(i.e. wave barriers) are needed to protect and restore offshore
cane beds. Because lower water levels are unlikely to be
tolerated by most Winnebago pool users, the Department of
Natural Resources developed a plan to raise the profile of the
bottom of the cane beds by dredging sediments, consisting mostly
of sand, from the lake bottom adjacent to the West Bay Canes,
and depositing them in openings within the cane beds. So
instead of lowering water levels, parts of the cane beds are
made shallower by adding sediment as needed. A pilot dredging
project conducted in 2010 successfully increased cane density by
up to 600%.
The
restoration project is sponsored by the Wisconsin Department of
Natural Resources in cooperation with the Lake Poygan
Sportsmen’s Club. Funding is provided by the Fox River/Green
Bay Natural Resources Trustee Council as part of restoration of
natural resources negatively impacted by PCBs in the lower Fox
River and Green Bay. The specific, targeted resource for
restoration at the West Bay Canes is the endangered Forster’s
tern. Current project funding is $182,000, provided from the
Fox River PCB Natural Resources Damage Assessment funds. These
funds are acquired through settlements with those companies
responsible for past releases of PCBs into the lower Fox River.
For more
information contact:
Art Techlow,
Wisconsin DNR at (920) 424-3001
Dan Rudebeck,
Lake Poygan Sportsmen’s Club at (920) 836-3643
Figure 1
Map of West Bay Canes
Figure 2
Dunage Blocks with warning buoy and lights
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