South East Queensland Floods: Tidal Riverbank Recovery
There are eleven major river systems that form the estuaries that lead out into Moreton Bay and the open coast of South East Queensland (SEQ). Healthy riverbank vegetation in the tidal zone is essential to maintain the quality of this coastal environment. With a growing population, it will become increasingly important that we all do our part to protect and maintain our local estuaries. Healthy tidal riverbank vegetation, which includes mangroves, provides a number of benefits to you, the wider community of SEQ, and our environment.
A time for action
The January 2011 floods had dramatic impacts on the property and lives of hundreds of people across SEQ. Flooding also had dramatic impacts on Brisbane River habitats. As a result of the floods around 90% of the mangrove vegetation along the upper reaches of the Brisbane River is now dead, dying or damaged.
Mangrove seedlings are often washed in on the tide, and given the opportunity, new mangroves will become established along the river. You can help the mangroves recover by leaving the standing dead trees on the shoreline, as these provide protection for the new seedlings while they become established. Remember, mangroves are protected from disturbance under Queensland law.
Benefits to you
Shoreline Protection – Trees are great bank defenders
January 2011 floods caused widespread river and creek bank erosion throughout SEQ. Trees and shrubs growing along the river are one of the cheapest and most effective ways to protect your property from erosion. Tree roots reinforce the soil, while trunks and branches break up the water flow and reduce surface erosion.
Mangroves in particular are excellent at holding the riverbank together and protecting your property from erosion during floods. Boat wave wash and tidal water movements can contribute to bank erosion in areas unprotected by mangroves or hardened walls. Growing with their feet in the water, mangroves work to hold sediment amongst their roots and reduce erosion from waves and tidal currents. Without the mangroves, banks are exposed to fast flowing water which can cause serious erosion.
Visual amenity – Vibrant vegetation in your backyard is visually appealing
With careful landscape design you can have great views of the river, attractive gardens, and healthy riverbank vegetation. We all enjoy greenspace, and riverbank vegetation provides a visually appealing shoreline throughout urban centres.
Benefits to the environment
Habitat – The river is a wildlife highway
SEQ is home to literally thousands of different plants, animals and birds. Some of these species are found nowhere else in Australia, making it important that we protect them here in SEQ. Riverbank vegetation, including mangroves, provides both land and water based animals with food and protection from predators, and acts as a ‘corridor’ for wildlife to pass from one area to another. In urban centres, this fringing strip of trees along the river is commonly one of the few remaining continuous green corridors through which wildlife can confidently move through the city.
Benefits to the community
Fisheries production – If you like seafood, you like mangroves
Australia’s mangroves provide important shelter, nursery and feeding areas for commercial fish, crabs and prawns. Many species targeted by recreational fishers need mangroves to survive. Mangrove jack, bream, whiting and flathead rely on mangroves to complete their lifecycles.
Kidneys of the coast – A healthy Moreton Bay needs healthy riverbank vegetation
The health of Moreton Bay relies on good water quality. One of the most important roles of riverbank vegetation is as a buffer between activities which happen on land and the health of the water. The vegetation filters out particles of sediment which can contain toxins and nutrients from our roads and backyards. Mangroves are particularly efficient ‘filters’, which is why they have been coined the ‘kidneys of the coast’. Mangroves take up excess nutrients coming off the land, protecting dugong, sea turtle and fisheries habitats throughout Moreton Bay.
Mangroves store carbon
Forested riverbanks, like all forests, work to remove carbon from the atmosphere and store it as woody material. Mangroves are particularly efficient at storing carbon. Mangrove trees accumulate up to five times the carbon stored in tropical forests due to their ability to store large amounts of carbon in the muddy sediments surrounding them.