May 10, 2010
Restoring an Ocracoke salt marsh
By PAT GARBER
“No
wetlands, no seafood” is the logo on a bumper sticker from the North
Carolina Coastal Federation (NCCF.) It is quite appropriate,
therefore, that one of the group’s latest projects is restoring
wetlands on Ocracoke Island.
The
federation teamed up with the North Carolina Center for the Advancement
of Teaching (NCCAT) to replant an acre of marsh at what was formerly
the Ocracoke Coast Guard Station and is now an NCCAT teaching
campus.
Recognizing
the importance of coastal wetlands not just for producing seafood but
for a number of ecological reasons, the federation wrote a grant for
funding to buy 25,000 marsh grass plants and set aside the last part of
April to work with NCCAT teachers, community volunteers, and students
from Ocracoke School in planting them.
North
Carolina’s coastal wetlands, or salt marshes, edge the soundside shores
of barrier islands and the mainland and may extend for hundreds of
miles along intercoastal waterways, wherever the water is saline.
They filter and clean our ground water, provide flood control, and
provide vital habitat, not only for the permanent marsh dwellers, such
as ribbed mussels and periwinkles, but for many of our ocean and
estuary species as well. Young fish and shrimp find food and
shelter in the creeks that meander through salt marshes.
Coastal
wetlands are comprised for the most part of three kinds of grasses,
each occupying a separate ecological zone in the marsh. The North
Carolina Coastal Federation purchased starts of all three species to be
set out during the week, and volunteers waded in shallow water and
tramped through sand to plant them.
Spartina
alterniflora, or marsh cordgrass, grows in the sub-tidal zone, which is
inundated by estuary water at each high tide. Its root system,
composed of rhizomes, spreads out like a net as it grows. When
marsh plants die, they are caught in this net. As they gradually
decay, they turn into rich alluvial soil, building more salt marsh and
constantly expanding into the sound.
Juncus
roemerianus, or black needlerush, inhabits the upper intertidal zone,
growing in areas that are covered by saltwater only during unusually
high tides. It has needlelike blades which were used by early settlers
for sewing.
Spartina
patens, known also as salt meadow hay, was planted farther inland,
above the high tide line, as it cannot survive regular tidal
inundation. This is the grass that used to provide fodder for
Ocracoke’s wild ponies.
The
project was coordinated with NCCAT’s professional development seminar,
“Planet Wetlands: Living Marshlands of the Outer Banks,” designed to
educate North Carolina teachers about the important part wetlands play
in the ecosystem. The restored wetland will serve as a living
classroom for teachers who come to future seminars. The 22
teachers who attended the April seminar participated in the planting,
getting hands-on experience in wetland restoration, as did the students
from Ocracoke School.
Ocracoke’s
U.S. Coast Guard Station property was transferred to the state of North
Carolina in 2001, and two years later money was allocated to reclaim
the eroded shoreline and provide protection for the property. In
2005, the Moffatt and Nichol engineering firm was engaged to design the
shoreline, after which an environmental assessment was developed and
the permitting process begun.
NCCF
coastkeeper Jan DeBlieu, who helped coordinate the project, said that
the federation had long conversations with NCCAT before deciding how to
stabilize the shoreline and finally decided upon constructing a rock
sill. Construction began in December of 2009, and the rocks
were laid so that water and fish could pass through the structure,
providing a safe zone where fish can feed.
NCCF
educator Sara Hallas worked with the Ocracoke School classes who
participated. Rita Thiel was among the teachers who accompanied
her class to the site. She described an activity, which she
called the rain-drop game, in which her fourth graders acted out the
role marsh grasses play in preventing the runoff of pollutants into the
sound. She said that the planting provided “an enriching and
engaging experience for the students to be involved in, showing how
each individual can have a positive impact for the good of their
island.
“They worked us hard!” she added. “Teachers and students were tired when we got back!”
Some
local Canada geese chopped off the tops of some of the grasses before
they were planted, but the project for the most part went well.
Not
all of the grasses are expected to live until next year. A 50 percent
survival rate is considered a successful planting. NCCF staff
will check back on the wetland next spring and replace grasses that
have died.
It
is hoped that gradually other marsh plants, such as sea oxeye,
glasswort, and marsh mallow, will move in and take hold in the marsh,
as well as marsh crabs, periwinkles, and similar native salt-marsh
inhabitants. Juvenile fish and shrimp have already moved into
some of the pools created by the rock sill, and should find the new
wetland a safe haven.
The
wetland restoration project is a good example of how different
organizations can work together to create positive results on many
levels.