The above photograph of the marsh across from the North East town park shows how much the invasive Phragmites have taken over the native cattail - the below article discusses this in some detail
Phragmites,
an invasive species of reed introduced to North America from England,
is often seen as a monster because the grass stalks grow up to 18 feet
tall and drive out native plants and wildlife.
But some scientists suggest the plant is more of a Dr. Jekyll and Mr.
Hyde, because while it is bad for plant and wildlife diversity it may
be good at protecting shorelines from erosion caused by rising sea
levels and climate change.
Patrick Megonigal, Deputy Director of the Smithsonian Environmental
Research Center, is studying the effects of rising carbon dioxide levels
on marshland plants, including phragmites.
“On the one hand, phragmites is very poor habitat for a lot of
animals –- birds, and even fish. But on the other hand, it is a
champion soil builder,” Megonigal said among the reeds and measuring
equipment at his wetlands research site, outside Edgewater, Maryland.
“And so we find places where the plant is dominant that the soil
elevation rises very rapidly, and that could be a good thing from the
point of view of preventing these marshes from drowning due to sea level
rise.”
This is not to say that Megonigal or anyone else is advocating the
intentional spreading of phragmites for erosion control purposes –-
first, because the rapidly-growing grasses don’t need any help
spreading; and second, because their roots emit a toxin
(trihydroxybenzoic acid) that kills other plants nearby, according to
research by the
Delaware Technology Institute.
Phragmites also crowds out wild rice, cattails, goldenrod, and other
native plants that wildfowl, muskrats, and other marsh dwellers need to
survive.
The
reeds, thought to have been brought to the Americas in the ballast of
ships by English colonists, have proliferated across the Chesapeake Bay
region and elsewhere in recent decades, because they thrive in disturbed
soil caused by development.
Over the last three decades, the invasive plant has multiplied
perhaps 10 fold to cover roughly 100,000 acres or about 10 percent of
Maryland marshes, according to an estimate by the Maryland Department of
Natural Resources. It has also spread widely across Virginia,
Pennsylvania and other states.
Jonathan McKnight, a biologist at the Maryland Department of Natural
Resources, said that phragmites roots form thick masses that hold soil
together. But he said that it would be wrong to plant phragmites to
protect shorelines, because the plant does not play well with other
forms of life.
“It would be great to find a silver lining in our phragmites
infestation,” McKnight said. “But it would be a lot better for us to
find a way to preserve marshes or maintain marshes with the native
material. Because even if you are protecting a phragmites marsh, a
phragmites marsh is not as good as the real native Maryland marsh.”
The
Maryland Department of Natural Resources, with help from the U.S. Fish
and Wildlife Service, spends about $30,000 a year spraying an herbicide
(glyphosate, the active ingredient in Round Up) from helicopters onto
selected stands of phragmites that are monopolizing the landscape in
important wildlife areas. Other states also conduct similar spraying.
Webster said glyphosate, which is used widely on farms and elsewhere,
dissipates quickly and does not pose a threat to fish or wildlife.
On a recent morning, Webster directed a helicopter with a tank full
of glyphosate as it launched from the top of a truck beside the
Nanticoke River. The helicopter swooped over green and gold marshlands,
then released the herbicides when over a stand of phragmites, which are
very tall reeds with fluffy seed heads.
“A
lot of homeowners on the Bay simply do not like phragmites just because
they do not have a view of the water” when the reeds are in the way,
Webster said. “But typically that’s not what we are out here to
achieve. We are doing this (spraying) to help wildlife.”
Webster said the state’s spraying of the weed from helicopters is
limited and not intended to totally eradicate the invasive species,
which he said would be impossible. Webster said Maryland is simply
trying to keep the phragmites in check in a few selected feeding grounds
for migrating waterfowl.
Dr. J. Court Stevenson, a professor at the University of Maryland
Center for Environmental Science who studies marshes, said in an email
that he is not opposed to spraying phragmites with Round-Up, as long as
it is done carefully, so the herbicide does not drift into other areas
and kill endangered plants.
Dr. Stevenson added, however, that over-use of Round-Up is creating
herbicide-resistant weeds that make farming more difficult. And he also
noted that spraying phragmites in some waterfront areas can increase
erosion, because of the reeds’ ability to hold shorelines together with
their dense roots.
“An example of where helicopter use appears to have been a problem is
at the Cove Point (Liquid Natural Gas) plant property on the Western
Shore, where the Phragmites rhizomes were holding the beach and
protecting it from excessive erosion,” Dr. Stevenson wrote. “After
extensive spraying over several years, the beach was breached causing
many the freshwater marsh plant populations behind the beach strand to
suffer.”
Officials with the Maryland Department of Natural Resources say they
try to be careful about where they spray phragmites, to avoid erosion
problems like this.
But the big picture is that sometimes it may be bad to kill
the monstrous Mr. Hyde of the marshes, because you will also lose the
good Dr. Jekyll.
By Tom Pelton
Chesapeake Bay Foundation