WETLAND VALUES AND
THREATS
What’s so special about your
wetland?
Perhaps it is the chorus of frogs on a warm
summer evening or the satisfaction of seeing the
same waterbirds returning year after year to
build nests and raise their young. As every
wetland is unique let’s investigate what
particular things you value about your wetland.
Animals (fauna)
What animals rely on your wetland? Animals
include water-bugs (macro-invertebrates) which
are at the bottom of the food chain, fish, frogs,
turtles, water-dependent birds, migratory birds
(such as Latham’s Snipe which comes from
Japan) and animals which live on the edge of
wetlands such as the Swamp Antechinus or the
secretive Australasian Bittern. Kangaroos and
wallabies passing through will also use wetlands
as a source of food and water.
Scenic
Do you appreciate your wetland as a natural
wonderland, a place of beauty? Maybe it’s your
favourite place to take photos or to view a
spectacular sunset.
Recreation
Wetlands are often used for recreational
purposes depending on their size and depth.
Do you use your wetland for fishing, yabbying,
boating, swimming or perhaps bird-watching?
Cultural heritage
Many wetlands were used by indigenous people
as a source of food and water. There may be
some visible signs of a past use in and around
your wetland. Examples include: shell middens,
oven mounds, scatters of stone artefacts, fish
traps and scarred trees (particularly red gum,
box trees).
Agricultural production
Wetlands can help agricultural production.
Perhaps your wetland performs some of the
following services:
 Improved water quality as wetlands are
a natural filter of sediments/nutrients
 Water supply for emergency use
 Provision of forage by controlled stock
grazing
 Control of agricultural pests by
waterbirds (eg ibis), dragonflies and
frogs which rely on wetlands for
breeding and refuge.
 Natural firebreak
 Ability to slow and absorb flood waters
Plants (flora)
Each wetland has developed over many, many
years its very own plant community. The type of
plants which are present depend on the water’s
depth, the length of time that water remains in
the wetland and whether that water is fresh,
slightly salty (brackish) or salty (saline).
What’s the problem?
Generally there are three zones within a
wetland:
Land zone – this zone is above the highest
water level. Plants occupying this zone cannot
tolerate flooding.
Edge zone – this is a wet/dry zone which
changes according to the water level. Plants are
able to tolerate both drying and flooding.
Submerged zone – this zone is usually under
water. Plants do not tolerate drying out.
Only healthy and intact wetlands can provide all
their wonderful benefits to the landholder.
Activities which threaten the services of
wetlands include:
 Drainage
 Impoundment
 rubbish dumping
 uncontrolled grazing
 clearance of wetland vegetation
Prepared February 2010
Corangamite Catchment Management Authority ABN: 60 355 974 029
PO Box 159, 64 Dennis Street, Colac, Victoria, 3250
t: 03 5232 9100 f: 03 5232 2759
e: info@ccma.vic.gov.au w.www.ccma.vic.gov.au
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WETLAND VALUES AND
THREATS
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wetland plants and this prevents their
regeneration.
weed invasion
pest animals
excess nutrients
salinity
competition for limited water resources
Clearance of wetland vegetation
Wetland plants (and algae) form the basis of
complex food webs which sustain a large variety
of life including frogs, fish and waterbirds.
Plants within the wetland and on its edges:
 provide a home both above and below
the water for animals as well as nesting
material
 help to bind the soil, preventing erosion
of soil and suspended sediment in the
water
 filter the water
Drainage
The biggest threat to wetlands throughout the
world is full or partial drainage. There is a loss
of all the vital services which only a wetland can
provide – natural water filtration, flood control,
alternative water source – as well as a loss of
habitat for the plants and animals which call that
wetland home.
Impoundment
Keeping your wetland permanently full of water
is harmful to the healthy functioning of your
wetland. Wetlands should be allowed to
fluctuate naturally with the seasons as
constantly impounded water may encourage the
growth of blue-green algae, pest species such
as carp and mosquito fish, saltier water
(salinisation), and less variety in plants and
animals. The drying out of wetlands allows
collected sediment to disperse with the wind
preventing the wetland from silting up.
Weed invasion
If weeds are not controlled in your wetland they
will gradually replace the native plants which
should be there.
 Common weeds around wetland edges
include Yorkshire Fog-grass, Tall wheatgrass and Phalaris.
 Willows compete with native plants for
space, water, light and nutrients.
Willows can dry out a wetland as they
use more water than native plants. As
willows spread by wind-borne seed and
offshoots, a willow by your wetland has
the ability to spread not only throughout
your wetland, but into neighbouring
creeks and rivers.
 Dry wetlands give the opportunity for dry
land weeds to spread throughout the
bed of the wetland. It is not necessary
to manage these weeds as they will be
naturally controlled with the return of
water to the wetland.
 A native plant which is sometimes
considered to be a weed – but isn’t – is
Azolla, a free-floating fern which
sometimes forms a dense layer over the
water. See Excess nutrients below.
Pest animals
Rubbish dumping
Wetlands in the past have often wrongly been
considered a good place to dispose of all kinds
of rubbish - household, garden, farm, chemical.
The answer lies in disposing of waste properly rubbish doesn’t belong in a wetland.
Uncontrolled grazing
Grazing wetlands at the wrong time and in an
uncontrolled way can severely damage the soil
and plants and add manure to the wetland.
Animals can easily trample (pug) wet soil,
destroying both plants and the soil structure
(pugging also creates the perfect micro-habitat
for breeding mosquitoes)
Some wetland plant species are very palatable
to stock – particularly young tender plant shoots.
Animals can also eat the seeding heads of
Prepared February 2010
Corangamite Catchment Management Authority ABN: 60 355 974 029
PO Box 159, 64 Dennis Street, Colac, Victoria, 3250
t: 03 5232 9100 f: 03 5232 2759
e: info@ccma.vic.gov.au w.www.ccma.vic.gov.au
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WETLAND VALUES AND
THREATS
Foxes, cats, rabbits, carp and mosquito fish are
the most common feral animals posing a threat
to wetlands.
The water found within a wetland can vary from
fresh, brackish (slightly salty) to salty (saline).
A wetland may be naturally salty – there are
many wetlands like this throughout our region –
and plants and animals have adapted to these
conditions.
Pest animals destroy native plants and compete
with and/or eat our native species. So even if
your wetland provides a valuable nesting site for
an endangered wetland bird, the chances of its
chicks being raised successfully may depend on
how well you are controlling the foxes.
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A brackish wetland may become more saline as
it dries and this too is a natural process which
will be remedied by sufficient rain diluting the
salt concentrations.
An integrated approach is always the
best method for pest animals. See your
Department of Primary Industries
website for further information.
The natural drying cycle of a wetland
controls carp and mosquito fish. Think
about how you may prevent pest fish
from re-entering your wetland
High salinity in a freshwater wetland may be the
result of saline groundwater entering the wetland.
Competition for limited water resources
As water resources become more limited
collecting water run-off before it enters the
wetland or extracting water from the wetland can
result in poor water quality, salinity and loss of
habitat.
Excess nutrients
Water runoff received from the land surrounding
a wetland can contain:
 residues from fertilisers/herbicides
 erosion/sediment
 animal manures
During times of drought wetlands provide an
emergency water supply for stock however it is
important to consider that wetlands also provide
water and habitat for a range of threatened
plants and animals which may be already
stressed by the current conditions.
Nutrient-rich water can cause a reduction in
water quality and algal blooms.
If the small wetland plant Azolla is flourishing in
your wetland it can be an indication that excess
nutrients are present. In the short-term, Azolla
can be used to clean up the excess nutrients
and then the Azolla can be removed by using a
garden rake (you can use the Azolla on your
garden/compost).
In the long term, run-off containing nutrients
should be managed through good landmanagement practices and by maintaining, or
increasing, the buffer zone around your wetland
to act as a filter.
Salinity
Prepared February 2010
Corangamite Catchment Management Authority ABN: 60 355 974 029
PO Box 159, 64 Dennis Street, Colac, Victoria, 3250
t: 03 5232 9100 f: 03 5232 2759
e: info@ccma.vic.gov.au w.www.ccma.vic.gov.au
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