Battling buffel to protect our desert jewel

Buffel Grass. Photo Mike Chuk/Julia Harris.

Bon Bon Station Reserve in South Australia is a true outback marvel, an expansive landscape dotted with shimmering salt lakes, red dune sands supporting mulga trees, open ironstone plains studded with stately myall trees and stunningly beautiful expanses of pearl bluebush.

But Bon Bon’s beauty is threatened by an invasive weed that has been proliferating in Australia since the 1860s, a species some ecologists have called ‘the botanical equivalent of the cane toad’.

Buffel grass (Cenchrus ciliaris) is an aggressive coloniser that's displacing Bon Bon’s native species and stripping its soils of precious nutrients. Alarmingly, it's also highly flammable. Areas suffering infestations of buffel grass experience wildfires so hot they have the potential to transform entire woodlands (such as the South Australian mulga) into grasslands of a single species.

More than 70,000 litres of herbicide mix has been used at key sections of Bon Bon Station. Photo Mike Chuk/Julia Harris.

The invasive weed is native to Africa and Asia, and is believed to have arrived in Australia 150 years ago with Afghan camel trains. Cattlemen took an interest in the grass when they discovered it was drought resistant and able to withstand heavy grazing, and it quickly became the pasture grass of choice among graziers in northern Australia. It's now moving south, often along roads, adapting to more temperate climates where it's not wanted.

Thankfully, however, the species has now been declared a weed in South Australia. At Bush Heritage’s Bon Bon Station, reserve managers Mike Chuk and Julia Harris are leading one of the largest buffel grass eradication projects taking place on a single property in Australia.

Burning after poisoning helps eliminate seeds. Photo Mike Chuk/Julia Harris.

“In the pastoral districts of South Australia buffel grass has the potential to outcompete native plant species and change the fire regime to produce hotter, more severe wildfires, as well as altering habitats and impacting on biodiversity,” Mike says.

It’s the major weed threat on Bon Bon Station Reserve.

Since 2013 more than 70,000 litres of herbicide mix has been sprayed on Bon Bon Station Reserve to specifically target buffel grass. Overall, a 65km length of the Stuart Highway has been treated, along with a further 55km of minor roads and 2km of creek line.

Volunteers have put in thousands of hours battling the pest grass. Photo Mike Chuk/Julia Harris.

In a systematic approach to bringing infestations under control, this work has been carried out concurrently by Bush Heritage volunteers, SA Main Roads, the SA Arid Lands NRM Board and the Native Vegetation Council.

While work continues on the ground, Bush Heritage will also embark on a new science and research‑based approach to better understand the impact of buffel grass. Honours students from Flinders University will join Bush Heritage Ecologist Aaron Fenner to investigate the impact of buffel grass on biodiversity.

It’s hoped that by better understanding how buffel grass interacts with native species, we can eventually introduce more robust and targeted strategies to eradicate it.

“The battle against buffel grass at Bon Bon will continue for many years,” Mike says. “Continued vigilance, monitoring and regular treatment will be key, along with supporting community efforts to reduce the weed in surrounding areas.”