To survive in any habitat an organism must be adapted to the conditions
existing there. In shoreline habitats the chief environmental factors
include climate, water level, salinity, oxygen level, carbon dioxide level,
water and air temperatures, and substrate. Any variations in these
factors can have a profound influence on the plants and animals living
in the shoreline communities.
Water level exerts a strong influence on the shoreline habitats.
As the tide changes the water level alternately exposes and submerges areas
of the shoreline. Habitats along the shoreline are divided into zones
based on tidal changes while elevation and slope of the land determine
how far the zones extend into a habitat.
COASTAL PLAIN FORESTS
Forest types in the coastal plain include upland and lowland hardwood forests,
mixed hardwood and pine forests, natural pine forests and pine plantations.
The coastal plain contains nearly half of the forests in North Carolina.
These forests are in danger of being logged faster than they can grow because
of the growing demand for lumber and wood chips and urban sprawl. More
trees are being cut, thus narrowing the gap between new growth and logging.
Along the water's edge, forests are a mixture of evergreens and deciduous
trees. Their hardy root systems take up large amounts of nitrogen and phosphorus
that would otherwise pollute estuarine waters.
FRESHWATER WETLANDS
Freshwater wetlands recharge groundwater and act as natural filters, trapping
pollutants before they enter the waters. Wetlands cover 4.7 million acres
of North Carolina -- 17 percent of the state. Of those wetlands, 95 percent
are in the eastern part of the state. Estimates are that between 35 percent
and 55 percent of the state's original wetlands have been lost or significantly
degraded during the last 200 years. More than 70 percent of species listed
as endangered, threatened or of special concern in North Carolina depend
on wetlands for survival.
RIVERS
Eight major rivers flow through North Carolina emptying into coastal estuaries.
The headwaters of these rivers once began in forests and wetland bogs.
Rivers contain vital freshwater that mixes with the sea to create productive
estuaries. They also provide food and habitat for fish to spawn and grow.
Today, all the state's rivers are polluted to some extent. The pollution
comes in many forms: storm water runoff from cities, suburbs, agricultural
farms and hog operations, sewage, industrial discharges, and air pollution
from factories and cars. Recent estimates are that nitrogen loads into
the Neuse River have increased 60 percent to 70 percent during the past
century. The 5,000 dams that have been built along North Carolina's rivers,
tributaries, and streams block fish from reaching their nursery grounds.
ESTUARINE SHORELINE
Estuarine shorelines encompass the zone between the upland areas and the
waters that flood the marshes. These lands are the last line of defense
against water-borne pollutants. A forested shoreline can remove as much
as half of the nutrients and bacteria in runoff before it reaches estuarine
waters. Experts believe that hurricanes and other natural processes alter
the growth patterns of shorelines keeping them in a constant state of change.
Common species in these areas include loblolly pine, red maple, sweet gum,
swamp tupelo, and live oak. The understory usually contains red bay and
wax myrtle.
Primary nursery areas are shallow estuarine waters with the highest
abundance and diversity of juvenile fish. These waters are home and spawning
grounds to economically important fish and shellfish. They also offer food
and protection to the young of many species. Only four percent of North
Carolina's 2.1 million acres of estuary are designated as primary nursery
area. These areas are essential to helping produce almost half of the fish
commercially harvested on the east coast of the United States.
SALT MARSHES
Salt marshes are found along 4,500 miles of shoreline along the state's
coastal sounds, creeks and rivers. They filter the water, protect the land
from erosion, and provide food and shelter to countless creatures. Salt
marshes that fringe open waters tend to be much more productive than those
further from the water's edge and less influenced by tides. As sea level
rises, salt marshes maintain themselves by migrating landward. Waterfront
property owners build bulkheads along an estimated 16 miles of shoreline
each year, killing this valuable habitat.
DUNES & BEACHES
Beaches are generally regarded as flat sea shores, but are often a part
of a complex dune and ridge system along an ocean shore. They can be sandy
or rocky. Particularly popular for recreation, short term high densities
of people can have serious effects on nesting animals and vegetation of
beach systems. Pollution (particularly bacteria from sewage and human waste)
and other results of large human populations have resulted in an increasing
number of beach closures in the U.S. and other countries. These pathogens
can cause a wide variety of diseases that threaten the public health.
OPEN WATERS
Open waters encompass the mouths of coastal rivers and the sounds that
lie between the barrier islands and the mainland. North Carolina has approximately
2,032,875 acres of estuarine open water. The salinity is about 35 parts
salt per thousand parts of water (ppt) along the outer coast and drops
to zero ppt up the tributary tidal creeks and rivers. Estuarine water can
become layered, with deeper waters being saltier than surface waters. Nutrients
are relatively scarce in clean estuaries because they are taken up rapidly
by plant life. In normally productive coastal waters too much nitrogen
will cause harmful algae blooms and low oxygen conditions. Nutrients find
their way into estuaries from overland storm water runoff, sewage, and
rainfall. Scientists suggest that 30-50 percent of nitrogen input into
estuaries comes from rain, and much of this comes from sources only 60-100
miles away.
SHELLFISH BEDS
Shellfish beds are areas in tidal creeks, rivers and near-shore estuarine
waters where shellfish such as oysters and clams live. Nearly 5,900 oysters
can grow in an area of one square yard. One of them can purify almost 1.5
gallons of water an hour because they extract nutrients with their gills
as they feed. In 1996, about 95 percent of the oysters and clams caught
in North Carolina came from the waters between Cedar Island and the South
Carolina border. Within the state, 363,733 acres of waters are permanently
closed to shellfishing because of pollution. Most of the remaining high
quality shellfishing areas in the state are also contaminated when only
two inches of rainfall occurs within a 24-hour period.
REFERENCE:
-
North Carolina Federation - State of the Coast Report
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