Ngarkat: How prescribed burns impact on bushfires
NPWS prescribed burns were successfully used to reduce the impact of two major bushfires in Ngarkat Conservation Park in 2025. One bushfire travelled straight into a 2021 prescribed burn area overnight which halted its forward rate of spread. This provided firefighters with options to contain the fire, which otherwise would have burnt over a quarter of the park. Another bushfire started on the same day, briefly slowing down in the early evening, as it came across a fire access track and 2020 prescribed burn site. This gave firefighters more time to control the fire, reducing its spread and impact on the landscape.
Here we take a closer look at how carefully planned fuel reduction played a critical role in managing these bushfires.
The story of the bushfire
Early in the evening of 10 March 2025 thunderstorms with dry lightning travelled across Ngarkat Conservation Park igniting fires south of Piggery Track and near Mount Rescue. Once the fires established unstable weather helped fan them westward. By 4am on 11 March the temperature was 23 degrees, peaking at 36 by mid-afternoon, with relative humidity forecast at 27%.
That evening CFS and NPWS staff fielded numerous calls as there was a massive glow over the park. But where, and how many fires, was still to be determined.
Satellite detection confirmed the general locations that night, as crews and plans were being organised, ready to go at first light. The fire was declared a major incident and aircraft mapped the remote locations of two fires and provided images while crews were being briefed. Data from the aviation team showed fires in areas where prescribed burns had previously been undertaken. This gave crews confidence that they could control these bushfires a lot earlier than if the fires had ignited in an area where there had been no fuel reduction works.
The Piggery bushfire travelled 16 km before it hit a 2021 prescribed burn site. This stopped the forward rate of spread giving firefighters easier and safer options to control it. In addition, a series of prescribed burns along Ngarkat Highway in 2023 gave the CFS Incident Management Team assurance to apply more aggressive tactics, as they knew firefighters had safer access and refuge while fighting the fire from this control line.
The bushfire near Mt Rescue started much closer (2 km) to a drought-affected 2020 prescribed burn area, and much earlier in the evening while conditions were still unstable, so the fire intensity was much greater as strong winds pushed it westward. However, the lower fuel loads in the prescribed burn footprint and adjacent fire access track did help slow the fire down. The tools used here to support bushfire suppression - prescribed burns and fire access tracks - interrupted the fire front, but under extreme weather conditions the bushfire was still able to push through.
The bushfires were active for a further 3 days followed by 7 days of mopping up and patrolling to make sure they didn’t reignite before the area was declared safe.
Close to 9,400 ha burnt (approximately 3.5% of the park) with staff and contractors spending weeks after the fire making some areas safe and rehabilitating an estimated 100 km of bushfire control lines.
CFS acknowledged how NPWS prescribed burns played a crucial role in controlling these fires, helping ground crews stop their spread, along with protecting critical habitat of the nationally endangered Mallee whipbird and Mallee emu wren.
The park; Ngarkat Conservation Park
Ngarkat Conservation Park in South Australia's Murraylands is a 271,000-hectare reserve. It’s the largest remnant patch of native vegetation in this agricultural district and forms a critical ecological corridor into Victoria, connecting 1 million hectares of important habitat for many significant birds, mammals and reptiles.
Visitors enjoy exploring the mallee in this park by 4-wheel drive or on walking trails, and camping under the stars. It is made up of fire-dependent heath and mallee habitats with over 250 leased bee sites, surrounded by grazing and cropping land.
Beautiful as it is, the park is an extremely difficult environment to suppress bushfires in. The size of the park, lack of access and water, steep sandy terrain and the often-rapid rate of bushfire spread, all contribute to a volatile environment.
NPWS fire management strategies are designed to help maintain a fire regime with prescribed burns, to create a mosaic of large areas of vegetation of different ages to benefit local plants and animals. They also help reduce the chance of the entire park, or large areas in it, from burning in a single, uncontrolled bushfire, risking local plant and animal extinction.
The issues
There is a high likelihood of bushfires in Ngarkat every year or two because of the presence of highly flammable heath communities and regular summer lightning storms. Heath vegetation is adapted to fire and uses it to boost regeneration and reset aging habitat. Left unchecked though, these fires are naturally big and historic land clearance means the landscape is less tolerant of large fires as there is less unburnt habitat left behind for plants and animals to recover in.
While vegetation communities in Ngarkat have slightly different needs, large areas of mallee and heath between 10 and 30 years old, with intermittent patches of younger heath and older mallee, benefit most species. They include threatened mallee birds such as Mallee whipbird and red-lored whistler. Western pygmy possum and heath goanna also require a mosaic of older and recently burnt habitat for ideal breeding and food needs.
The planning; learning from fire
After every major bushfire the NPWS regional team reassess it prescribed burn program. A catastrophic bushfire in 1999 saw strategies put in place to stop a repeat of a fire of this size. Prescribed burns were placed on the western side of Ngarkat Highway in 2009/2010 to help with this long-term strategy. When a 2014 bushfire burnt close to one third of Ngarkat along with other large areas in this Mallee region, the team analysed it by overlaying the bushfire footprint onto the 2009/2010 prescribed burn footprints. This showed how the burns influenced the bushfire’s size and potential impact, demonstrating just how effective prescribed burns can be, and was used to plan future burn sizes and placements.
Between 2019 and 2021 prescribed burns were then placed on the western side of the 2014 bushfire footprint to provide firefighters a strategic advantage in suppressing bushfires in the southern and central areas of the park, should they occur. The strategy also provided protection through the middle of the park as the bushfire footprint recovered.
The tactics appear to have worked as prescribed burn sites from 2019 to 2021 were successfully used to fight the March 2025 bushfire.
Mosaics reduce risk and protect habitat
Taking this knowledge further, the team is strategically segmenting the park using burns to reduce bushfire risk across the entire park. Smaller burns in mallee heath don’t tend to hold or influence bushfires, unlike larger burns (>400 ha) which have proven to reduce the spread and impact of bushfires.
Larger burns also mimic natural fire across this vegetation type and reduce fuel loads more effectively, while providing pockets of younger habitat. This helps species such as the native silky mouse thrive as it gleans additional food from recently burnt areas temporarily made more abundant with grasses.
The aim of these prescribed burns is to strengthen suppression options, making bushfires easier to manage, using areas previously burnt by bushfires or prescribed burns. They also help reduce the risk of large blocks of key habitat burning in a single event and provide a mosaic of different vegetation ages.
Managing the park’s fire regime includes managing the size of fires. A bushfire under 10,000 ha is tolerable, based on the scale of the landscape, against the risk to life, property and the environment. Prescribed burns provide options to help manage these risks.
Fire history strengthens learnings
Ngarkat provides many lessons from its long fire history which have led to important adaptions in strategic fire management. The team continues to review how well the burn program meets its objective to reduce the impact of bushfires.
The focus is on minimising impacts to environmental values such as Mallee bird habitat by working with fire across the landscape, while also helping to maintain long unburnt vegetation and access to commercial and tourism opportunities for the region.
