@article {bnh-8129, title = {Kangaroo Island Black Summer fire reconstruction}, number = {685}, year = {2021}, month = {07/2021}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

In the 2019-20 summer, wildfire affected an area of around 200,000 hectares on Kangaroo Island, South Australia, in what has become known as the Black Summer, with significant ongoing social, economic and environmental impacts.

The Advanced Himawari Imager (AHI) onboard the geostationary satellite Himawari-8 provides infrared imagery at 2km spatial resolution at nadir in 10- minute intervals. This allows wildfires to be detected and monitored in quasi-real time using the Biogeographical Region and Individual Geostationary HHMMSS Threshold (BRIGHT) algorithm (Engel, Jones and Reinke, 2020), developed in partnership between the Royal Melbourne Institute of Technology (RMIT) and the Bushfire and Natural Hazard CRC. This report outlines the methods used to verify hotspots detected by the BRIGHT algorithm and reconstruct the Black Summer fires using spatio-temporal clustering.

}, keywords = {black summer, Fire, fire impacts, kangaroo island, reconstructions, remote sensing, Satellite}, issn = {685}, author = {Simon Ramsey and Karin Reinke and Nur Trihantoro and Simon Jones and Chermelle Engel} } @article {bnh-8192, title = {Risk mitigation from prescribed burning in Kangaroo Island and Mount Lofty Ranges - Black Summer final report}, number = {690}, year = {2021}, month = {08/2021}, institution = {Bushfire and Natural Hazards CRC}, address = {MELBOURNE}, abstract = {

According to the Independent Review into South Australia{\textquoteright}s 2019-20 Bushfire Season, conditions were the worst on record with fires resulting in the loss of three human lives, 196 homes, 660 vehicles, 68,000 livestock, $200m of agricultural production. Around 280,000 ha were burnt by the fires, including total or partial burning of several National Parks.

The Bushfire and Natural Hazards CRC commissioned this project as part of a larger set of Black Summer fires research projects aimed at understanding the record-breaking fire season. This project focuses on answering questions about the effectiveness of prescribed burning, also known as hazard reduction burning, in mitigating risk in two areas affected by fires during the season: The Mount Lofty Ranges east of Adelaide, and Kangaroo Island.

The key questions were:

  1. How does risk respond to treatment in Kangaroo Island, an area with little formal quantification of prescribed burning benefits and costs?
  2. What was the risk in the leadup to the 2019-20 fire season in the Mt Lofty Ranges, and how will risk change in the next five years as a result of the implied fuel reduction from the fires, as well as alternative prescribed burning strategies?

These questions were answered using a well developed methodology combining large scale fire behaviour simulations and Bayesian risk quantification. Similar analyses have been carried out for a range of case study landscapes in southern Australia as part of the Hectares to tailor-made solutions CRC project, with results available online via the end-user tool the Prescribed Burning Atlas, and also the NSW Bushfire Risk Management Research Hub{\textquoteright}s projects for the NSW Bushfire Inquiry.

We found a clear relationship between the rate of prescribed burning and area subsequently burnt by wildfire in the Kangaroo Island case study. This translated into reductions in loss of life and property as well. Risk mitigation was more sensitive to edge treatment than landscape treatment, although both reduced risk. Conversely, increasing treatment (particularly at the edge) resulted in higher areas of the landscape exposed to vegetation being burnt below its minimum tolerable fire interval.

In the Mt Lofty Ranges, we found complex patterns of risk are likely in the aftermath of the 2019-20 fires. In the absence of further wildfire events, risk of area burnt is likely to rise substantially by 2025, regardless of prescribed burning rates, with a similar result for vegetation exposed to too frequent fire. However, risk sto life, property and infrastructure are projected to remain similar to current levels.

Our work contributes to the evidence base for prescribed burning planning in South Australia, with future work potentially examining new management values (e.g. smoke health costs, new biodiversity measures) and exploring empirical relationships between prescribed burning and fire-affected area in 2019-20.

}, keywords = {black summer, kangaroo island, mitigation, Mount Lofty Ranges, Prescribed burning, risk}, issn = {690}, author = {Hamish Clarke and Brett Cirulis and Owen Price and Ross Bradstock and Matthias M. Boer and Anthony Rawlins and Trent Penman} } @article {bnh-7240, title = {Effects of the January 2020 bushfires on estuarine systems of Kangaroo Island: post event field data collection}, number = {603}, year = {2020}, month = {08/2020}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

The 2020 summer bushfires on Kangaroo Island were the largest in the Island{\textquoteright}s recorded history, with over 200,000 hectares and more than 40 \% of the island burnt (DEW, 2020). The impacts of these bushfires will not be confined to the terrestrial landscape and are likely to have substantial detrimental impacts on the island{\textquoteright}s aquatic systems, particularly after rainfall.

Post-fire exposed soils are highly erodible, and therefore intense precipitation events or seasonal rainfall can result in the runoff of nutrients and ash enriched sediments, debris and other products of combustion into waterways. These runoff events, allied to heavy sedimentation, can lead to deteriorating water quality, potentially triggering eutrophication, low oxygen events, and compromise aquatic fauna. In addition, contaminants, including trace elements and products of combustion such as polycyclic aromatic hydrocarbons (PAHs) can also enter waterways (Olivella et al 2006, Shakesby and Doerr, 2006, Smith et al 2011, Sequeira et al 2020).

One area of concern in Kangaroo Island are the estuarine systems downstream or adjacent to burnt areas. Despite the ecological importance of estuarine environments and the multiple ecosystem functions they provide (including nursery grounds for juvenile fish), the impacts of bushfires in estuaries are yet to be investigated. Furthermore, because estuarine systems in Kangaroo island are not permanently open to the sea, the impacts of accumulated soot, ash and sediment channelled into estuaries could be exacerbated, and have the potential to disrupt complex ecological and biogeochemical cycles, increase contaminant loadings and result in pervasive effects for local fish communities. Ultimately, there are substantial knowledge gaps in our understanding of water quality impacts and mobilisation of heavy metals and isotopes in the aftermath of bushfires in estuaries, and these add to the lack of understanding of the ecology and geochemistry of estuaries in South Australia.

In this context, the Bushfire and Natural Hazards CRC, via the their quick response funding, provided financial support for travel-related expenses to undertake surveys on Kangaroo Island in estuaries within areas directly affected by this unprecedented bushfire season, and control sites outside these areas. These sampling events are part of broader research where in the long term, we aim to evaluate the impacts of bushfires on estuarine water quality and on estuarine fish, as well as trace the mobilisation and fluxes of contaminants released by bushfires into estuarine systems.

}, keywords = {Bushfire, data collection, estuarine system, kangaroo island}, issn = {603}, author = {Patrick Reis-Santos and Bronwyn Gillanders} }