Tiny Dung Beetles Deliver Big Climate Win for Australian Farmers

Small insects could play a major role in reducing livestock emissions while improving pasture health.

Dung beetles may be small, but new Australian research has revealed they could make a significant contribution to reducing greenhouse gas emissions from livestock farming, cutting methane released from cattle manure by an astonishing 85 per cent.

The study, led by researchers from Southern Cross University and the University of New England, is the first in Australia to measure the direct impact of dung beetles on greenhouse gas emissions from cattle dung. Published in the journal Ecological Entomology, the findings highlight another valuable benefit these insects provide to Australian agriculture.

While dung beetles have long been recognised for improving soil health, burying manure, recycling nutrients and reducing bush fly populations, researchers have now shown they also play an important role in reducing the environmental footprint of grazing systems.

Over a 90-day trial conducted in northern New South Wales, scientists compared cattle dung pats colonised by four introduced dung beetle species with untreated dung pats that contained no beetles.

The results were remarkable.

Methane emissions from dung containing beetles remained almost non-existent throughout the study, while untreated manure produced significant methane spikes during decomposition. Overall, cumulative methane emissions were reduced by 85 per cent, while the total greenhouse gas footprint of decomposing manure fell by 18 per cent.

Southern Cross University researcher and co-author Professor Nigel Andrew said the beetles effectively changed the way manure decomposed.

“By tunnelling and aerating the dung, these beetles disrupt the oxygen-poor conditions that methane-producing microbes require,” Professor Andrew said.

Instead of producing high-impact methane, the decomposition process shifts towards aerobic respiration, creating conditions where more of the carbon is released as carbon dioxide, which has a substantially lower global warming effect than methane over the short term.

Researchers also discovered that although most beetles had left the dung by about Day 23, the tunnels they created continued to influence decomposition for the remainder of the experiment, demonstrating that their impact lasts well beyond their physical presence.

The research focused on four introduced dung beetle species: Euoniticellus intermedius, Euoniticellus africanus, Euoniticellus fulvus and Onthophagus granulatus.

Australia has more than 500 native dung beetle species, but these evolved alongside marsupials and are generally not suited to processing livestock manure. Between 1968 and 1992, the CSIRO introduced more than 20 overseas species from Africa, Hawaii and southern Europe to help manage the large quantities of dung produced by cattle and other livestock.

Today, these introduced beetles are well established across many grazing regions, including parts of northern New South Wales.

For producers across the Northern Rivers and NSW North Coast, the findings are particularly encouraging. The region’s beef and dairy industries could potentially benefit from healthier soils, improved pasture productivity, reduced pest flies and lower greenhouse gas emissions through maintaining active dung beetle populations.

The researchers believe encouraging healthy beetle populations could become an important, low-cost tool as governments and industry continue developing strategies to reduce agricultural emissions and improve carbon accounting.

Co-author Jean Holley said the research builds on the already impressive list of services provided by dung beetles.

“This study adds to the already impressive repertoire of ecosystem services that the humble dung beetle provides to Australian agriculture,” Ms Holley said.

“Not only do they recycle nutrients, reduce fly numbers and aerate the soil, but they may also help to mitigate greenhouse gas emissions from livestock production.”

As Australia’s livestock sector faces increasing pressure to improve environmental performance while maintaining productivity, the humble dung beetle may prove to be one of farming’s most valuable and cost-effective allies.