Bushfire risk to life and property
The figure below shows the Barwon South West region’s risk profile for the period 1980–2019 and projected changes in bushfire risk until 2022. It shows:
- in 2018–19, bushfire risk was 62%
- bushfire risk fell sharply in 1983 after the Ash Wednesday bushfires, which caused devastating losses along the Surf Coast and in the eastern Otways
- bushfire risk steadily increased after the Ash Wednesday fires as fuel re-accumulated across the landscape, reaching a peak of 79% in 2002
- since 2008, bushfire risk has fallen by 15–20% as a result of the strategic, risk-based approach to fuel management
- fuel management activities are projected to reduce risk to 51% by 2022, but without any fuel management, we project bushfire risk will increase to 74%.
Bushfire risk profile, Barwon South West Region, 1980–2022
Bushfire risk to the environment
The figure below shows the tolerable fire interval (TFI) status of vegetation on public land in the Barwon South West region since 1980.
The figure shows that about 27% of the vegetation was below minimum TFI in 2018–19, with minimal changes in the TFI distribution having occurred since the previous reporting year.
In 2018–19, less than 1% of the vegetation in this landscape was burnt by bushfire or planned burning while below TFI.
TFI status of vegetation on public land in Barwon South West region, 1980–2019
The figure below shows the growth stage structure (GSS) status of vegetation on public land in the Barwon South West region since 1980.
The figure shows that about 18% of the landscape was in the juvenile and adolescent growth stages in 2018–19. Compared to 2018, there was a small increase in the amount of vegetation in the juvenile growth stage (from 3% to 4%), while the amount of vegetation within the mature and old growth stages remained relatively constant. This is the result of the succession of Tall Mist Forest and Tall mixed forest into the mature growth stage, following previous fires in 1939 and 1999, respectively.
GSS status of vegetation on public land in Barwon South West region, 1980–2019
The TFI and GSS cannot be determined on public land with no recorded fire history.
Activities to reduce bushfire risk
Table 7: Barwon South West region fuel management, 2018–19
Fuel reduction | Hectares |
|---|---|
Area treated by planned burning:
| 7,020 |
Area treated by other fuel management methods | 2,000 |
Total area treated to reduce bushfire risk | 9,020 |
Victorian Bushfire Monitoring Program
The Barwon South West monitoring program has focused on monitoring fuel hazard and mapping the severity and extent of burns. There has been pre- and post-burn fuel hazard monitoring for all burns, where access has permitted, to assess the effectiveness of the burns against the burn objectives.
Burn severity mapping ensures fire history is accurately recorded. The mapping data is essential for the modelling we conduct using Phoenix RapidFire and FAME.
During the year, we investigated fine-scale mosaic burning in the Anglesea Heath to confirm our hypothesis that this burning results in positive outcomes for flora and fauna and reduces risk, assuming that habitat and bushfire fuel respond positively to regular, low-intensity mosaic burning. We collected remote camera and habitat structure data in a burn in the Anglesea Heath to test our hypothesis and assumption. This will be a long-term monitoring effort, and we will use what we find to decide whether to conduct this type of burning more broadly in future.
Coastal Wattle is a species that is expanding beyond its natural range, and it is causing structural change and loss of biodiversity throughout the region. This species also affects our fuel management activities: we cannot safely do planned burning in heavily infested areas, which limits our ability to reduce risk and conduct ecological burns.
A monitoring project in 2018–19 mapped the severity and extent of its current range: accurate mapping will give us the information to treat Coastal Wattle before we do planned burning, which will:
- improve the outcomes of burns intended to reduce fuel and therefore bushfire risk
- return the forest to a more-natural state, improving diversity where there has been structural change.
Monitoring Coastal wattle will also help land managers control the spread of the species and enable an appropriate fire regime.
During the year, several fire research projects were underway in the region.
We worked with Deakin University to better understand fine-scale refugia and their importance for small terrestrial mammals, particularly in relation to predation. We intend to use our findings when setting burn objectives, and they may also help us to construct refuges if planned burning or bushfires are likely to affect areas with vulnerable species.
We worked with The University of Melbourne to better understand the interaction of fire-altered habitat and predation. The findings will help us align planned burning and predator control programs.
We engaged a data specialist to ensure all relevant ecosystem data is accurate and in a format we can use for decision making. We engaged The University of Melbourne to use the data to replace our previous modelling inputs (which had been derived through expert elicitation), focusing initially on providing fire-response data for several key fauna species.
Page last updated: 23/12/20