Mapping Buffel
Join host Matthew Taylor and intern Ella Raymond, to hear about her research project focussed on using remote sensing technology to map buffel grass at our Ethabuka and Pilungah reserves in South West Queensland.
Among the jagged breakaways and sprawling chenopod country of Evelyn Downs Reserve, land management activities are well underway to address threats to the recovery of the reserve’s native vegetation. Located roughly two hours' drive north of Coober Pedy, Evelyn Downs is our largest reserve. At 234,694 hectares, it covers an area comparable in size to the Australian Capital Territory – or even the United Kingdom. In the year since we acquired the reserve and began managing it for conservation, we’ve monitored and planned efforts to control weeds found on the reserve.
– Graeme Finlayson, Healthy Landscapes Manager South Australian Arid Rangelands“Surveillance efforts will focus on invasive Buffel grass (Cenchrus ciliaris) and targeted removal of Prickly Acacia (Vachellia farnesiana), which is choking some of the creek lines in the eastern part of the reserve.”
Another spiky pest is a large stand of prickly pear cactus, located in one of the vast and beautiful Red Gum-lined creeks. It presents a significant challenge to remove. Prickly pears were first introduced to Australia during the beginning of European colonisation but only rapidly spread through the arid interior in the mid-1900s with the arrival of species from the Americas. The plants grow prolifically and are incredibly hardy, surviving a wide range of seasonal conditions. They outcompete native plants, pose injury risks to native animals with their spines, and provide refuge for a multitude of other invasive species, including fruit flies, rabbits and foxes.
“Their seeds are spread by birds and other species that eat the cactus fruit, each of which contain over 100 seeds. They can also propagate from broken-off sections of the plant, which are easily moved during flooding events or carried by other invasive animals such as donkeys, horses, cows and camels.”
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Prickly pear at Evelyn Downs Reserve, Antakirinja Matu-Yankunytjatjara and Yankunytjatjara Country, SA. By Ingo Schomacker
Control methods of the cactus include chemical, physical and biocultural approaches. Biocontrol is completed through use of the Cochineal bug (Dactylopius opuntiae), but efficacy of this method is dependent on the species of prickly pear.
“At Evelyn Downs we’ve found that one of the cactus species has been successfully treated with the bug,” says Graeme. “Funnily enough, most people have consumed their fair share of Cochineal, it’s the source of carmine, the red food colouring commonly found in sweets like gummy bears, Skittles, and a range of other goodies.”
The local Landscapes group has been breeding up colonies of the bug to help with cactus control in the nearby Gawler Ranges. They’ve provided Graeme and his team a sample of the infected cactus, which will be trialled at Evelyn Downs.
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Cochineal bugs getting to work on a prickly pear at Evelyn Downs Reserve, Antakirinja Matu-Yankunytjatjara and Yankunytjatjara Country, SA. By Ingo Schomacker
“By attaching infected segments with skewers to plants in the field, the Cochineal can get to work and spread throughout the infestation. Their activity is influenced by temperature, and there haven’t been many trials in this region, so we have a great opportunity to study the success of this method,” says Graeme.
In addition to the biocontrol methods being tested – which could prove incredibly efficient for the remote and harder-to-access areas of the reserve – contractors have also mapped the infestation and are undertaking chemical treatment.
"Given the scale of Evelyn Downs and the importance of broadscale threat mitigation in some hard-to-reach areas across the reserve, innovative approaches to land management, such as biocontrol, are important to returning country to good health.”
