By Jennifer Nichols
Published by ABC Rural, 19/09/2021
Landholders could unwittingly be killing some of the most valuable members of their herd by failing to minimise the impact of drenching farm animals for parasites. Researchers are urging people to actively care for dung beetles, which can dramatically reduce fly numbers and greenhouse gas emissions while aerating and fertilising the soil.
The potential value of dung beetles on the carbon market is being investigated as part of a five year, $23 million dollar national research project to deal with the 80 million tonnes of livestock dung Australia has to contend with each year. As part of the project, Russ Barrow from Charles Sturt University is organising workshops around the country and encouraging Landcare groups to breed the beetles. “If you talk to a farmer from 50-60 years ago they’ll talk about backs that were black on white shirts because of the fly numbers, and they’ve dropped off massively, so it is a brilliant, brilliant effort that the dung beetles have done,” he said.
Unlike cane toads, dung beetles are a biological control success story. A CSIRO program that ran from 1964 into the mid-1990s imported dung beetles from southern Africa and southern Europe, with 23 introduced species now established in Australia and more entering quarantine for evaluation, to fill seasonal gaps in beetle activity in southern Australia.
Many native species of dung beetle are not equipped to deal with larger moister cattle dung.
Before the exotic beetles were introduced, dried cow pats as hard as rock fouled pastures and polluted creeks and dams during rain events, providing the perfect breeding ground for flies and parasites.
“But now we’ve got these beetles operating in cattle and sheep dung, burying that dung up to a metre into the soil,” Dr Barrow said.
“The soil is no longer hard and compacted, air and moisture can infiltrate into the ground and the fly breeding capacity has dropped dramatically.”
Consultant Paul Meibusch from the Colere Group said farmers needed to think about managing dung beetles just like other livestock.
“With some of the calculations that we’ve made in our other projects, dung beetles could be worth over $100 a hectare per year in the work they’re doing,” he said.
“So why wouldn’t you want to make sure they’re working really well?”
Dr Barrow said drenching farm animals for parasites cuold kill dung beetles and their larvae and needed to be managed to minimise the impact.
One way to achieve that is by limiting the spread of the chemicals in dung across the land.
“I’m not suggesting to anybody that they don’t drench — it’s an animal welfare issue,” Dr Barrow said.
“But if you’ve got a big enough property, one of the things that we recommend is to sequester your animals into one paddock for a couple of weeks — depending on the form of drench, some can take six weeks to pass through an animal.
“Even on farms which have drenched constantly we still find dung beetles, so we can have even greater abundance of dung beetles on farms by managing the drenching regime.”
The project led by Meat and Livestock Australia (MLA) and Charles Sturt University’s Graham Centre for Agricultural Innovation was launched in 2018.
Now at the halfway point, MLA innovation manager Doug McNicholl believes the worth of dung beetles is still severely underestimated.
“Some of the interesting and emerging opportunities are around the carbon and biodiversity markets,” he said.
“We’re going to see the value of beetles really come to the fore.”
Teams of researchers are looking at everything from helping producers identify which beetles are active in what regions and when, as well as importing beetles to plug “seasonal gaps” in activity in southern Australia.
One group is focussed on rearing and releasing beetles, while a small team is doing economic modelling.
With more than 26m head of cattle nationwide dropping about 12 pats every day, the insects have their work cut out for them.
“The beetles bury dung into the soil and that can promote things like carbon sequestration and storage,” Mr McNicholl said.
“They’re helping plant growth while avoiding things like nitrous oxide and methane formation as dung decomposes.”
Over the next two and a half years Gympie and District Landcare will be visiting properties to help landholders conduct field audits and collect, identify and spread dung beetle species.
“Once we know what species are there, then we will be either building on existing species or adding new species to people’s properties,” biocontrol manager Yvonne Hennell said.
She already breeds insects to help control the invasive cat’s claw creeper and madeira vine.
“Eventually we want to look at extending our biocontrol facility and actually rearing dung beetles at Landcare,” Ms Hennell said.
Landcare’s role will be important as demand for dung beetles from insect breeders outstrips supply and pushes the price of the insects up.
As part of the national project there is also a free MyDungBeetle Reporter app that allows people to load up to four photographs and GPS locations of sightings to experts across the country for identification and mapping.
• The beetles play a crucial role in burying the dung of introduced livestock and reducing the spread of disease, flies and parasites
• Experts say the beetles should be cared for like other animals on farms
• They also say financial benefits can accrue rapidly with good management
By Jennifer Nichols