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The Five
Subsystems of Wetlands
MARINE
WETLANDS
Saltwater wetlands along coasts.
Water
levels rise and fall with the daily tides; can be subject to the
force of waves and storms, and to ocean currents. Characteristics
of marine wetlands vary with the level of tidal, wave, and current
affects. Salt-tolerant plants called halophytes are dominant. Common
halophytes include grasses such as the Spartina species. Subtidal
marine wetlands are submerged continuously; intertidal marine wetlands
are periodically exposed.
ESTUARINE
WETLANDS
Coastal wetlands within estuaries (where fresh & salt water
mix).
Estuarine
wetlands usually have some access to oceans, with significant inflows
of freshwater. Water levels rise and fall with the daily tides;
can be subject to the force of waves and storms. Characteristics
vary with the level of tidal, wave, and amount of salinity, which
can vary with location and interactions with oceans and freshwater
sources. Salt-tolerant plants called halophytes are dominant. Common
halophytes include grasses such as the Spartina species. Subtidal
estuarine wetlands are submerged continuously; intertidal estuarine
wetlands are periodically exposed. Mangrove swamps are considered
estuarine wetlands. The mangrove trees feature distinctive roots
known as prop roots, which at low tide look like intricate lacework
of branches reaching into the water. When exposed, prop roots absorb
oxygen from the atmosphere. Mangrove seeds disperse by floating,
and can live more than one hundred days.
RIVERINE
WETLANDS
Wetlands in the channels of rivers and streams.
They may develop upstream where the water velocity is faster and
the dominant bottom surface is rocky; these riverine wetlands
feature animals associated with fast-moving water, such as caddisflies.
Riverine wetlands also form along slower-moving streams and rivers;
their bottom is often muddy, and they support more vegetation
and animals adapted to slow-moving water. Riverine wetlands are
part of the riparian, or streamside, habitat. Riverine
wetlands are usually inland wetlands.
LACUSTRINE
Wetlands around lakes and reservoirs.
These freshwater wetlands form around the perimeter of lakes and
reservoirs. They are larger than 20 acres or contain water depths
in excess of 6 feet. Like marine and estuarine wetlands, lacustrine
wetlands are exposed to wave action.
PALUSTRINE
Isolated, inland wetlands not associated
with lakes or reservoirs. Smaller and shallower than lacustrine
wetlands, palustrine wetlands include wet meadows, bogs, potholes,
and playas.
Find
out what species live in wetlands ...
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