Wetlands reborn a reward in sustainability
From the magpie geese to the mighty Barramundi and even a few crocodiles, the rehabilitation of a wetland adjacent to the Great Barrier Reef has also brought with it recognition for the traditional owners who bought back their land.
Mungalla Aboriginal Business Corporation recently won the 2016 Minister’s Award for Leadership in Sustainability as part of the Queensland Premier’s Awards. They were also finalists in the prestigious Banksia Sustainability Awards.
They’ve been responsible for restoring the Mungalla wetland, a vital ecosystem near Ingham, north of Townsville, adjacent to the Great Barrier Reef and a nursery for reef fish.
Wetlands make way for ponded pastures
When the Nywaigi people bought Mungalla Station in 1999, they knew their battle to truly reclaim and restore the land was only just beginning.
Around one quarter of the 880 hectare station is covered by wetlands, but these wetlands were choked by invasive weeds such as water hyacinth, hymenachne and aleman grass. The waters were so starved of oxygen that they were nearly barren of fish and bird life.
It wasn’t always this way. Older members of the Nywaigi people could recall when the wetlands were so full of life that the sky was black with magpie geese. The wetlands also hold great cultural value to the Nywaigi, but when Mungulla became a cattle station in the 1940s, an earth wall was built which blocked tidal flows into the wetlands and which turned them into freshwater which allowed for ponded pastures for the cattle.
After unsuccessfully tackling the weeds with herbicide, the traditional owners asked CSIRO to help them develop a weed management and water quality plan that would restore the wetlands to their natural state.
A simple fix brings startling results
For a complex problem, the answer turned out to be remarkably simple: remove the wall and let the salt water do the rest.
CSIRO landscape ecologist Brett Abbott and hydrological modeller Fazlul Karim said their hydrological modelling suggested that removing the earth wall – called a bund – would allow the salt water to reach around 500 metres inland on a high tide, while research by a masters student working with the team also showed that salt water immersion was likely to kill many of the weeds.
So the wall came down, and the results stunned everyone involved.
“After the first year, it was all open water and we thought a few more birds would come in, particularly wading birds, but by the following year the amazing thing was the native Bulkuru sedge and the native lily pad just came and filled the place,” Abbott says.
Extreme weather events worked to their advantage: not only were 2014 and 2015 both quite dry, which allowed the salt water to sit around in the wetlands for longer than usual, but two offshore cyclones ended up driving the sea water up to 1.2 kilometres inland.
Even the scientists involved were amazed at how quickly the wetlands were restored. Mike Nicholas and Tony Grice began work on the project at CSIRO in 2006. Mike is now a national resource management consultant, was surprised by its early success.
“My history is working in rangelands, and the pace of change in rangelands is a lot slower; if you destocked a paddock in the rangelands and kept it destocked for 15 years you might see change,” he said. “We got change within the first tidal inundation – it was just startling.”
Fish nursery reborn
Within just two years, all the weeds were dead and the wildlife – including a crocodile or two – had returned.
“It’s now healing itself, as the salinity flows back into that wetland,” said Jacob Cassady, director of the
Mungalla Aboriginal Business Corporation that now owns the station. “It’s killing all the noxious weeds that have propagated there and it’s beginning to regenerate; the fish have come back, the bird life has come back.”
The magpie geese have returned, along with nearly 280 other species of native bird. The waters are now home to at least nine species of fish, and serve as nursery grounds for some commercially and recreationally important reef fish such as barramundi and mangrove jack.
Education and investment opportunity
It’s an environmental success story that is also serving as a valuable educational opportunity, Cassady says.
“People are coming from all over the world to see our wetlands now,” he says. “It’s all about educating people about the importance of having an environmental conscience in terms of looking after country.”
The flourishing wetlands have also attracted tourists, and there are plans for an elevated walkway through the wetlands that would help to bring in tourist dollars to be reinvested into ongoing rehabilitation efforts.
What does it mean for the reef?
Cassady also stresses the importance of raising awareness not just about the coastal wetlands, but about the health of the Great Barrier Reef in general.
It’s possibly the first time that a bund has been removed to rehabilitate a wetland, despite the fact that there are well over a thousand similar barriers up and down the Great Barrier Reef coastline.
“Two-thirds of the Great Barrier Reef is under significant bleaching, and that should be alarming, every Australia should be alarmed,” he says. “Have they forgotten that this is one of the seven wonders of the natural world and we just take what we’ve got in our backyard for granted?”
The project’s success has also been recognised with a 2014 Queensland Premier’s Reconciliation Award, at the 2016 Queensland Premier’s Sustainability Awards received the Minister’s Award for Leadership in Sustainability, and was a finalist in this year’s national Banksia Sustainability Awards.
For Nicholas, the rewards of the project are as much social as they are scientific.
“The wetland that we’re working in has a traditional story, and to restore the balance in that wetland is significantly important to the traditional owners,” he says. “When we had our workshops, one of the traditional owners said ‘healthy country, healthy people’.”