Friday, March 1, 2013

Be Kind to Canes

Reprinted from the Oshkosh Scene newspaper with additional photos of cane beds and birds that nest  in them.

The East Channel Canes on Lake Poygan may seem to have a strange name, but once upon a time there was a corresponding West Channel Canes, and even more surprising is this is the place where the Wolf River used to empty into Lake Poygan. Now these few scattered cane beds are all that remain of a huge wetland complex destroyed by flooding, waves and ice. Without restoration these too will be lost.

On the Lake Winnebago Upper Pool lakes there is a rare habitat called cane beds that are popular fish, wildlife, and the human enthusiasts that follow them.  These beds are composed of a native strain of Common Reed (Phragmites australis).  Our native strain is an important part of Wisconsin’s wetland ecosystems, but there is a variety originating from Europe that is highly invasive.  These aquatic plants are the remains of wetlands lost since the damming of the Fox River in the 1850’s.  Where it was firmly rooted it survived the breakup of the surrounding marsh and the near permanent flooding.   Although they are tough plants, and survived the high water, they too have been slowly fading away. 

Forster's Tern chick hiding in reeds
Historically several of the cane beds have been used by colonies of the endangered Forster’s Tern.  If you have never seen a Forster’s tern, picture a gull and cross it with a jet fighter.  These birds are fun to watch.  Terns will cruise around the lakes searching for small fish, and when a bird spots one it begins to hover.  Then locked on its prey, the tern drops from the sky, wings partially folded back, and plunges into the water.  The bird briefly disappears and then flies up and away.  Depending on the time of year the tern may give the fish to its mate, or one of its chicks.  These terns are endangered because their nesting habitat, floating mats of vegetation, are no longer that common.  On the Winnebago Upper Pool Lakes, the cane beds have shrunken and so has the Forster’s Tern population.

click below to see more of the cane beds

Why are the cane beds disappearing?  The main reason is they really don’t belong where they are.  Common reed grows best on wet, but not flooded wetland soils, not in standing water year after year.  In such waters they are vulnerable to ice, wave and flood damage.  It is obviously important not to break off living stems of these plants in deep water, but what is far less obvious is that it is equally important not to break off dead stems.  The dead stems act as breathing tubes and drive oxygen down into the roots were it is especially needed in early spring before the plants send out green shoots.  Driving a snowmobile through the beds in winter or a boat in spring breaks off the stems at or below the waterline and the lack of oxygen to the roots stresses or kills the plants. 
If you enjoy fishing the canes, stay out, motor around and fish the edges.  If you duck hunt, never run your motor through the canes, and take care to damage as few stems as possible while concealing yourself.  If you enjoy swimming near the canes, never tie your boat up to or throw an anchor among them.  If we take care of them they will last longer, but they require management beyond individuals being kind.  Water level management needs to be changed to allow for better growth, and sediment that has washed away over the last 160 years may need to be returned.  Only with proper management and respectful use will they last another 160 years.  

Photos of bird nests in the cane beds:

Ground nester
American Bittern Nest and Eggs
Endangered Species
Injured Forster's Tern, this tern was taken to a wildlife rehabilitator but later died.  
wetland birds
Yellow-headed Blackbird nest and chicks, tipping over as cattails bend
Bird Colony
Forster's Tern Nest and Eggs

native Phragmites australis
Lake Butte des Morts cane bed east of Terrell's Island

No comments:

Post a Comment