Wetlands are iconic in Australia. Images of birdlife flocking to inland seas as dormant plants spring to life and frogs sing a ridgey-didge chorus could slot right into a QANTAS ad (the true test of Australiana).
You might even say that they bridge the gap between droughts and flooding rains.
But did you know that wetlands are vital for Australian ecosystems? They’re biodiversity hotspots, environmental filters, and even store carbon. Pretty neat for a big ol’ puddle!
But as usual with our most essential places, wetlands exist in a delicate balance that can be upset by human impacts.
Banrock Station is a South Australian winery that knows the importance of wetlands and has seen first hand what can happen to them.
Wetlands make up 75% of the property and since 1993 the station has been actively restoring the wetlands into a healthily functioning ecosystem.
In fact, in 2002 Banrock Station was listed as a Ramsar Wetland, part of an international convention for protection of significant wetland ecosystems.
We spoke to their Wetland Manager Tim Field to learn about how they’ve been restoring wetlands at the station, but first, what exactly is a wetland and why are they so important?
What Makes a Wetland a Wetland?
In the simplest terms wetlands are what they say on the tin – they’re wet land. The water can be fresh, brackish or full on saltwater and importantly, wetlands don’t need to be wet all of the time.
As long as an area gets inundated sometimes, whether regularly or randomly, it could qualify as a wetland.
‘So what?’ you might be thinking, ‘lots of areas get wet sometimes’. You’re not wrong, but the key factor for wetlands is adaptation by the local flora and fauna to the wet soil, which acts kinda differently to regular soil.
Plant roots respire (just like humans!), they take in oxygen and release carbon dioxide. But when soil is soaked the oxygen can’t get through, the soil becomes what’s known as ‘hydric’ soil and the roots have to rely on anaerobic processes to survive (ones without oxygen).
There are other adaptations too.
Waterbird species rely on the abundance of food during floods for breeding events and River Red gums like the ones found on Banrock Station produce seedlings as floodwaters recede.
As Tim says, ‘Each time it dries out new seedlings germinate, you can see the class of 2002, 2005 and 2008’. But the impact of wetlands goes far beyond supporting certain well-adapted species.
Why Wetlands Are Important to The Natural Environment
Wetlands do so much for the natural environment that it’s hard to know where to start, but one of their standout functions is maintaining water quality.
Wetland environments trap sediments that would otherwise flow downstream and they absorb excess nutrients that can upset the balance in our rivers.
‘The wetlands at Banrock Station have a high turnover, large amounts of water are filtered, sediment removed, and nutrients cycled,’ says Tim.
Another benefit is carbon drawdown. Trees can sequester carbon and wetlands are pretty damn efficient at this! Despite only taking up 5-8% of the earth’s surface, wetlands store between 20 and 30% of the earth’s total soil carbon.
The biodiversity found in wetlands is so intense, it’s comparable to rainforests and coral reefs. According to Tim Field, in the Banrock Station wetlands alone over 180 bird species have been recorded, along with over 350 species of plants.
And biodiversity like this isn’t just useful for maintaining healthy ecosystems, it ensures that they’re highly productive, which benefits our natural industries.
Many species of fish and crustacean breed and grow in wetland ecosystems, which then provide catch for our fisheries. Valuable species include Golden perch, Australian smelt, Bony bream, Blue Swimmer crabs, Yabbies, and Eastern King prawns.
Bird species also breed in wetlands, often during major flooding events, and their strong numbers are vital for controlling pest insect species and helping farmers avoid pesticides.
The water that wetlands store and secrete into groundwater is valuable to farmers too, they rely on it for irrigation and without healthy wetlands would struggle to water their crops.
The Banrock Station Wetlands
Situated 2.5 hours north east of Adelaide on the Murray River, Banrock Station is a large wetland complex that has been significantly restored.
The station is on the lands of the Erawirum and Nawait people and has significant cultural value to these groups, with middens and scar trees being found in the area.
Since the early 20th century the wetland had been permanently flooded thanks to weirs and locks on the Murray River, which wreaked havoc on the native species adapted to regular drying events.
In 1993 Banrock Station began restoring the 1,500 ha of wetlands and woodland that can be found on the property.
A vineyard was established, sheep, cattle, and carp were removed and the wheels were set in motion to return the wetlands to their natural state, which included a South Australian first: actively reestablishing the wet and dry phases that native species rely on.
Fast forward a few years and Banrock Station has achieved Ramsar certification (one of only 65 sites in Australia), become the number one bird watching spot in South Australia and in 2013 was chosen as the site for the reintroduction of the Spiny Daisy (Acanthocladium dockeri), an Aussie species that nearly went extinct.
Banrock Station is a great example of both the value of wetlands and how effective restoration projects can be. Somewhat surprisingly, the station is actually owned by Accolade, a large international winemaker, but this hasn’t detracted from the winery’s conservation efforts.
In addition to their work with the wetlands the station is working towards a goal of planting 100,000 trees and turning their wine range 100% vegan, with the goal of becoming Australia’s most sustainable winemaker.
The crew have been planting Mediterranean varieties recently, which in addition to saving water, grow well in the South Australian climate and produce exciting modern flavours.
Wetlands are places worth protecting. They have immense environmental, cultural and even economic value.