By Josef Schofield, Regional Operations Manager, Danae Moore, National Science Team member, Henry Brink, Newhaven Sanctuary Manager & Joey Clarke, Senior Science Communicator
It's a late afternoon in August at AWC's Newhaven Wildlife Sanctuary in Central Australia, and a light easterly breeze provides perfect conditions for burning. Clumps of spinifex crackle gently as they are ignited by a handheld drip torch along the edge of a sandy track, grasshoppers jumping ahead of the flames.
Fire in a boom and bust landscape
In Central Australia, dramatic cycles of boom and bust are driven by patterns in rainfall over long periods of time. The tempo in the desert is slower and less regular than the annual wet season that dominates in the tropical savanna up north. Here, a series of dry years (sometimes stretching more than a decade) is interrupted at intervals by years of dramatically higher rainfall, triggering a flush of new growth that ripples up the food chain. Insects multiply, burrowing frogs emerge from underground, Woodswallows and Budgerigars form huge, wheeling flocks. Water birds arrive to feed in the ephemeral lakes that appear, and the number of small mammals in our traps can increase by orders of magnitude.
Fire follows the same boom and bust pattern, with wetter years usually followed by years of widespread fire. The part of Central Australia around Newhaven - on Ngalia-Warlpiri and Luritja Country - was subject to a traditional Aboriginal fire management regime until the 1930s; a tight mosaic of numerous, mostly small-scale burns lit deliberately for a range of purposes. Fire is still a big part of life in the desert, but the displacement and disruption of European colonisation caused fire regimes to change. Following periods of above average rainfall, fire now sweeps across large areas of Central Australia, removing vegetation cover and food resources over vast areas and razing fire-sensitive vegetation communities. This changed fire regime is ecologically damaging, and compounds the threat posed by introduced predators to native animal species.
Objectives and planning
At Newhaven, the goal of AWC's fire management is to re-establish appropriate fire regimes that conserve species and ecosystems, and that restore ecological processes. It's a formidable job. AWC's small field-based team is tasked with managing the 262,000-hectare sanctuary in a landscape that is highly flammable, while taking into account the needs of different vegetation types, the vagaries of climate from year to year, and the legacy of complex, multi-year fire histories. To succeed in meeting its objectives, our program of prescribed burning must be led by strategic planning, informed by science, mapping and years of experience on the ground.
A lot of work goes into developing a detailed plan for prescribed burning activities each year. By analysing satellite imagery going back three decades, we're able to compile fire history maps which show the age of vegetation across different parts of the sanctuary. In spinifex-dominated vegetation communities, targets have been set for the proportion or area that should fall within particular age brackets (e.g., 3-10 years since last burnt, and so on). Critically, using fire history maps we can work out where to burn to break up larger, homogeneous patches into smaller areas of differently aged vegetation. Over the 2020-2021 summer, Newhaven recorded 300mm of rain, which set up good conditions to carry out planned burns later in the year.
Brad Leue/AWC Applying fire to support a rewilding project
A particular focus for the 2021 prescribed burning program is Newhaven's feral predator-free fenced area. At 9,450 hectares, it is the second largest safe-haven project on mainland Australia and is now home to a growing reintroduced population of Mala, as well as Red-tailed Phascogales and Brush-tailed Bettongs or Pututjurru, released in August. All are nationally threatened species, and at least eight other species are slated for reintroduction to the site. AWC is working to establish and maintain a fine-scale mosaic of vegetation of different ages within the reintroduction area, firstly to minimise the risk of any large-scale unplanned fires and secondly to increase the diversity of available habitat and resources for reintroduced mammals.
Careful fire management at Newhaven over the past 12 years has achieved great results - protecting fire-sensitive stands of mulga woodland and desert oaks, establishing a finer-scale mosaic of spinifex, and improving habitat for threatened wildlife. Thoughtfully applied, fire is an essential and positive part of conservation land management in Central Australia.
Read and download the full issue of Wildlife Matters here.
