Mangroves in the Northern Territory - Department of Land Resource ...

Why are Mangroves so Important?
Ecological importance
Coastal Stabilisation
Coastlines and beaches are dynamic. This means that
they are constantly changing as a result of both natural
and anthropogenic (man made) influences (Mastaller
1997).
Plate 57: Rhizophora stylosa (Stilt rooted mangrove - left) and
Bruguiera exaristata (Orange mangrove - right) on Lee Point
Beach
Mastaller (1997) states that natural processes which can influence coastal and
estuarine dynamics include
• longshore currents;
• wave action;
• wind action; and
• storm surges, including tropical cyclones.
Anthropogenic processes which can influence coastal and estuarine dynamics include:
• coastal development; and
• removal and destruction of coastal vegetation including mangroves.
In many cases natural processes are accelerated by human development and
populations. The rate at which coastal change takes place can be quite slow and may
only become evident over a number of years. However even gradual changes can
cause serious environmental and economic problems (Mastaller 1997).
The dense structure of mangrove communities results in a firmly anchored physical
wall of trees linked together through complex interlaced root systems. As a result
mangrove communities provide protection against coastal erosion by creating a buffer
against currents, waves, wind and storm events (Mastaller 1997).
In many regions of the world, including Australia, the removal of mangroves has
resulted in severe erosion and subsequent economic cost. The construction of artificial
barriers is structurally challenging due to the unstable nature of coastal substrates and
as a consequence is very expensive (Mastaller 1997).
Sediment Traps
Mangrove comminutes and their complex root systems trap large quantities of silt
which is carried downstream from rivers and other estuarine systems. By trapping
these tiny particles of silt and soil, mangroves act as a filter and consequently
contribute to the quality of coastal waters (Mastaller 1997).
Northern Territory Mangrove Education Kit
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