Cows are not the only animals which produce methane. In central Arnhem Land, water buffalo are causing their share of environmental headaches.
When access roads are flooded during the wet season, the Aboriginal town of Bulman in central Arnhem Land is often cut off from the “big smoke” of Katherine, some 300km to the south-west.
Yet the picturesque community has boasted a buffalo harvesting industry for the past 35 years.
The trade provides not just food for its population of up to 300, but also an income from mustering, by supplying beasts to a $30m-a-year buffalo export industry flourishing in Australia’s North.
But water buffalo – Bubalus bubalis – cause considerable damage to the environment, as Bulman folk well know.
The damage arises from the animals moving and feeding, with the Australian Government labelling them “a major environmental disaster in wetlands of the Top End”.
They also produce methane, and with an estimated 200,000 feral buffalo now wandering the wetter parts of the monsoonal North, that’s both a problem and an opportunity.
On the one hand, modelling published last month in the Journal of Wildlife Research revealed culling the beasts might yield substantial climate change benefits by reducing methane production.
The paper suggests a potential for carbon credits to incentivise culling.
On the other hand, that very idea drew criticism from the NT Buffalo Industry Council, which is keen to consolidate its growing export market.
The question breaks down to a choice between harvesting the buffalo – that is, mustering them to generate food and income – or culling to waste, often by aerial shooting.
The answer is complicated.
What is a water buffalo?
Weighing up to 1200kg, the water buffalo is a large herbivore found on floodplains, woodlands, and sandstone escarpments where rainfall is greater than 1000mm a year.
Between 1825 and 1849, about 80 water buffalo were imported to Melville Island and Cobourg Peninsula as meat for remote settlements.
After the settlements were abandoned in the mid-20th century, the buffalo colonised the Top End, with numbers reaching about 350,000 by the 1980s and sparking a cull as part of a Brucellosis and Tuberculosis Eradication Campaign.
Numbers have since risen and buffalo have again been declared a pest.
Damage on floodplains occurs when buffalo move along swim channels, destroying vegetation, and eroding soil by creating new drainage channels.
Swim channels can cause saltwater to intrude into freshwater zones, particularly the case near Mary River where this has caused loss of paperbark forest.
Water buffalo can also spread weeds, particularly Mimosa pigra, and reduce the nesting activity of protected magpie geese. They are also thought to hamper the nesting of crocodiles, protected under NT, Australian and international laws.
Buffalo and climate change
Controlling buffalo numbers has long helped protect northern ecosystems, but aerial extermination is expensive.
And, like camels, goats and deer, buffalo digestion produces methane, a potent greenhouse gas that contributes to global warming.
Researchers led by mammal ecologist Dr Hugh Davis of Charles Darwin University recently estimated how much methane buffalo herds produce.
By modelling buffalo populations on a parcel of land in the South Alligator River region of Kakadu National Park over 20 years, the scientists estimated how much methane production is saved by culling.
Turns out that was almost 90 kilotonnes a year of methane as CO2 equivalent.
After subtracting the cost of annual aerial control operations, the methane saving was estimated to be worth more than $1 million per year in potential carbon offsets.
“This approach could incentivise the control of numerous destructive feral animals,” Davis says.
“It has often been put in the too hard basket – such as feral camels in the outback, or the booming feral deer populations in Victoria, NSW, and Tassie.”
Harvesting buffalo on Aboriginal lands
An offset plan or policy would need to consult with buffalo “stakeholders”, including the export industry and Aboriginal landholders.
That list would include Mimal Land Management, an Indigenous-owned and operated organisation helping manage lands for Dalabon, Rembarrnga and Mayili landowners and the people of south-central Arnhem Land around the town of Bulman.
“We’re in the box seat on this whole question,” says Mimal CEO Dominic Nicholls, one of the significant harvesters.
“We harvest between 2500 to 4000 head per year, plus another 500 to 1000 that would come out of the area [as protein]; and our neighbours are harvesting.”
Nichols estimates the lion’s share of buffalo shipped as part of the NT’s $30m export market come wild from Arnhem Land and Indigenous land.
“[They] say about 16,000 was last year’s count,” Nicholls says. “Half of that is coming from Arnhem Land, all wild harvest.”
From Mimal’s contract mustering of buffalo, Aboriginal landowners collectively earn between $500,000 and $750,000 each year, which “goes through the land council and a royalty mechanism”.
“Traditional Owners have already told us they don’t want that taken away,” he says.
“There’s a bit of romanticism around buffalo, but the thing [landowners] value the most are the jobs and money that come out of it … even the eating.”
What’s the answer?
From Nicholls’ perspective, any offset scheme would have to cover far more than the cost of the culling, it would also need to cover what landowners would otherwise make from the buffalo.
But the problem is even more nuanced.
According to Mimal data, mustering and meat harvesting is not having any effect on actual buffalo numbers, with no impact on current herd sizes.
And that means culling may still need to be part of any successful buffalo management strategy, especially considering Nicholls predicts there is only so long a wild harvest will be economically and socially viable, and with the environmental damage still to account for.
“There’s not an indefinite income opportunity the way things are,” he says.
“The future is likely buffalo behind wire.”
As for any carbon offset, Nicholls suggests that for Mimal, any earning from carbon through culling or other removal method would only be viable if it was an equal return to what landowners make.
“It is viable but should be additional to existing activity.”
And a carbon abatement scheme must have “additionality”, he says.
“It can’t be something you were going to do already; the schemes are to encourage an activity that wasn’t already happening.”
The only answer right now then, is that there is no clear answer, and the immediate fate of the feral buffalo remains decidedly unclear.
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Originally published by Cosmos as Meat or carbon offset: A precarious future for northern feral buffalo
Dr Glenn Morrison is an award-winning journalist, researcher, and author who has written of Australia’s Centre and North for more than 25 years. A former newspaper editor, he has degrees in Science, Engineering and a PhD in media and cultural studies, and has lectured at several universities. As an adjunct senior research fellow at Charles Darwin University’s Northern Institute he is general editor of Borderlands, a literary journal of the Northern Territory. Glenn has written two books about the Red Centre and lives at Alice Springs.
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