Download Protecting Riparian Environments

FACT SHEET Protecting Riparian Environments
Working for our future – today
Protecting Riparian Environments
Riparian environments are important sources of life that play a major role in maintaining
waterway health and supporting recreational activities, such as fishing and swimming.
However, all processes within a riparian ecosystem are inter-related and can therefore be easily
disturbed if not maintained.
What are riparian environments?
Riparian (stream-side) environments encompass aquatic (water-based) and terrestrial (land-based) plants
and animals, as well as many abiotic (non-living) factors, such as temperature and humidity, that are
associated with a body of water.
Why are riparian environments important?
Riparian environments commonly host a greater diversity of plants and animals than adjacent upland
areas, primarily due to the higher moisture and nutrient content of the soils that adjoin water bodies. Once
established, riparian environments create a different climate within the local area (micro-climate) with
higher humidity and lower air temperature than surrounding areas. This provides an ideal environment for
many plant and animal species with specific habitat requirements. Riparian environments are considered
vital to the long-term sustainability of a catchment system, particularly relating to waterway health.
An example of a healthy riparian environment.
Threats to riparian environments
Development – Housing estates and commercial development
along the water’s edge commonly involve the removal of riparian
vegetation to provide better views and access to the water.
Sedimentation – Poor control of sediment on building sites
and insufficient vegetation to stabilise riverbanks result in
excess sediment being washed into our waterways. This creates
turbid (muddy) water with reduced light penetration, which has
impacts on aquatic plants and animals.
discharged from urban areas and industrial effluent can
heavily impact on the health of a waterway. High nutrient
loads commonly result in accelerated growth of plant species,
including aquatic weeds and algae, which can disrupt the
natural aquatic ecosystem and have a negative impact on water
quality. Furthermore, bacteria within the water that help break
down nutrients use oxygen during the process. High nutrient
loads therefore deplete dissolved oxygen levels in the water
column and can lead to fish kills.
Boat Wash – The wash from passing boats causes erosion of
the stream banks, increasing sediment load and depleting the
riparian landscape.
Dredging – Deepening waterways to allow navigation of boats
changes the stream hydrology, commonly resulting in stream
widening, which erodes the riverbanks, increases sediment loads
and impacts on the aquatic environment.
High nutrient loads – Unnatural pollutants in stormwater
Weeds– Sparse and fragmented riparian vegetation results in
greater light penetration and the opportunity for weed plant
species to thrive and out-compete native species. Riparian areas
that are dominated by weeds have decreased plant and animal
diversity. Weed species often have shallower root systems,
which compromise their role in bank stabilisation. (Note: Existing
weeds may be providing some bank stability and habitat, and it
therefore is important that appropriate weed control methods
are used.)
Benefits of riparian environments
Shading – Vegetation creates a natural buffer that
controls daily fluctuations in air temperature and minimises
evaporation of water. Reduced light intensity minimises
excessive growth of nuisance plants and algae. Shading
also alters the in-stream ecology, providing habitat for both
predators and prey.
Erosion control – Established riparian vegetation, including
a range of mature trees and understorey plants provide a
strong network of roots that help to stabilise soils and provide
strength to the stream bank. This prevents bank erosion
during high stream flows and therefore reduces sediment
loads entering the waterway.
Habitat – The diversity of vegetation that commonly exists
within riparian environments provides critical habitat for a
range of animals with specific requirements. The platypus,
for example, feeds on aquatic insects that live among the
dead leaves, woody stems and branches that accumulate
in established riparian areas. In a broader context, riparian
environments also provide wildlife corridors that enable the
movement of native wildlife and plants between remnant
habitats.
Natural filtration of runoff waters – Riparian vegetation
assists in removing a significant proportion of particulate
pollutants from runoff water via natural filtration through the
understorey, leaf litter and soil.
Flood and sediment control – Riparian vegetation helps
to reduce stream velocities and sediment transport during
high rainfall by creating greater friction along the stream
bank. This natural regulation of stream velocities allows for
controlled discharge of greater volumes of water without
flooding.
In-stream nutrient source – Native riparian vegetation is
an essential food source for many aquatic plants and animals
that rely on flowers, insects, leaf litter and other organic
debris that fall into the water. This helps to sustain complex
food webs by providing the basic nutrients for plant growth,
which ultimately form a major part of the diets of many
native fish and other aquatic fauna, such as turtles.
High water quality – The health of waterways usually
is reflected in the quality of the water. Established riparian
areas help to clean the water through physical and chemical
means. Aquatic bacteria, for example, are major contributors
to maintaining high water quality through the breakdown of
various nutrients.
Pest fauna – Degraded riparian vegetation results in poor
habitat for native fauna. Pest fauna, commonly with less specific
food and habitat requirements, out-compete native species
and dominate the riparian environment, resulting in reduced
biodiversity.
Livestock grazing – When stock access is not restricted,
substantial damage can be caused by overgrazing, weed
dispersal, formation of tracks, physical degradation of the
stream bank and water contamination through the high nutrient
content of dung and urine. Stock also can dislodge river rocks,
submerged or protruding logs and branches that provide habitat
and reduce water velocity.
Source: Healthy Waterways (South East Queensland Healthy Waterways Partnership).
FACT SHEET Protecting Riparian Environments
An example of native riparian vegetation impacted by weeds.
What you can do to improve the health
of riparian environments?
■■
If you live on a waterway, plant local, native species along
the stream bank and control weeds. More information on
environmental weeds is available online at: goldcoastcity.
com.au.weeds
■■
Reduce boat speed on the water to minimise boat wash.
■■
Restrict stock access by erecting fences at an appropriate
distance from the waterway.
■■
Get involved with local community catchment and
Bushcare groups. They are located throughout the Gold
Coast and help to preserve and improve the health of our
waterways.
■■
Stormwater pollution is a major factor affecting the
health of our waterways, and has a direct impact on
the health of riparian ecosystems. Learn how you can
reduce your contribution to stormwater pollution at
the household level by visiting: goldcoastcity.com.au/
stormwaterpollution.
Educate friends and family on the importance of riparian
environments and how they can help improve our
waterways.
Restoring established riparian vegetation is a long-term
process that may require initial tree planting and an
ongoing, long-term, weed control program to encourage
a rich diversity of native species. The Council is continually
undertaking works to restore and preserve riparian
vegetation throughout the Gold Coast.
The Council also is developing catchment-based
management plans for all major catchments within the
Gold Coast. They identify the issues that are impacting on
the health of our waterways, including degraded riparian
environments. These plans take into account all components
of the catchment system to make sure the management
approach is appropriate. Part of these management plans
is the identification of priority areas for restoration. This will
ensure the most effective use of labour and resources.
Community education programs and events provided by the
Council increase the community’s knowledge about the need
to protect our waterways and their supporting environments.
The long-term viability of waterways requires an integrated
approach, with concerted efforts by government, industry
groups and the general public. Please help to protect our
waterways. They are our future.
For more information
For more information on waterway health and community catchment groups, please
contact Council on (07) 5581 6722.
GCCC H9 080403
■■
Riparian restoration by Gold Coast
City Council