Abstract
in the American Geophysical Union
Transactions (EOS), 80 (17)
Soil and geochemical conditions
on Phragmites growth and their implications in controlling
the spreading of Phragmites
Hongbing Sun, Allison Brown
Department of Geological and Marine Sciences, Department of
Biology
Rider University
Kelly Hogan and Paul Steblein
Edwin B. Forsthe National Wildlife Refuge, Oceanville, NJ 08231
Soil and hydrogeochemical conditions are examined in the freshwater marsh
impoundment at Edwin B. Forsthe National Wildlife Refuge to study the factors
that favor the widespread monoculture of Phragmites. The organic
layers of the soil profile in the impoundment indicate a better aeration
condition for patches dominated by Phragmites than for patches dominated
by non- Phragmites plants. The aeration condition is reflected by the color
of hydric soils. A darker organic soil layer indicates a poorer degradation
of organic matter and more reduced conditions. The better aeration condition
around Phragmites’s roots might result from its large hollow stems
and deep rooting systems which facilitate the transport of air to the hydric
soil underneath. Examination of the soil in a nearby saltwater marsh dominated
by Spartina also shows a much darker organic layer in the soil profile
with strong H2S smell. This better aeration condition near the roots of
Phragmites facilitated by its stem implicates that controlling of
Phragmites with solely flooding by the management agencies may not be very
effective. Controlling of Phragmites by burning, which reduce
the stem elevation, coupled with long-term flooding might reduce the aeration
ability of Phragmites temporarily. But burning and long-term
flooding also suffocate the potential growth of freshwater plants all together.
Initial geochemical analysis of pore water shows a similar conditions
for the Phragmites and non- Phragmites dominated islands in the freshwater
impoundment. Based on the general zonation of Spartina and
Phragmites in the coastal marsh and our previous study in Stone Harbor,
NJ, it is our initial impression that saltwater tidal enhancement,
might be better in controlling Phragmite spreading in Edwin Wildlife Refuge.
But the complex fresh water resources in the freshwater impoundment might
compromise the saltwater tidal treatment. Further study will be needed
to examine the hydro-geochemical condition with the tidal enhancement.
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