Bushfire risk to life and property
The figure below shows
the modelled bushfire risk profile for Loddon Mallee for the period 1980–2019 and projected changes in bushfire risk until 2021. It shows that:
- in 2018–19, bushfire risk was 66%
- most risk is concentrated in a small number of localities, so the risk profile is very sensitive to small changes in fuel around these places (for example, burns around Wedderburn during the year helped reduce risk)
- more planned burning in smaller, vegetated blocks around larger, higher-risk communities (such as Inglewood, Wedderburn, Tarnagulla and Rushworth) led to a 13% drop in risk
- most of the remaining risk arises from private farming land and small parcels of vegetation, where it is more difficult to manage fuel with planned burning
- if we complete all the fuel management activities on the current Joint Fuel Management Program and there is little bushfire activity, modelled bushfire risk will slowly rise to 70% by 2022. If we cannot carry out any of our planned fuel management activities, modelled risk will increase to 79% by 2022 as fuel re-accumulates in high-risk areas we treated in 2017–18.
As fuel reaccumulates in high-risk areas, we prioritise burns that maximise community safety and re-burn them when enough time has passed for adequate fuel accumulation and/or maintenance of ecosystem health.
Bushfire risk profile, Loddon Mallee 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 Loddon Mallee region since 1980.
Nearly 78% — 1.62 million ha — of the landscape is comprised of the largely intact Mallee land systems, namely Murray–Sunset, Hattah–Kulkyne, Big Desert, Wyperfeld and Little Desert. Natural fire regimes and planned burning in these systems drive the trends shown in the TFI figures.
The figure below shows that in 2018-19 the proportion of the vegetation below minimum TFI was 28% (a decrease of about 2% from the previous year), while the proportion of vegetation within TFI was 28% (an increase of about 3% from the previous year). The figure also shows that the proportion of vegetation below minimum TFI has remained fairly constant in the region since 1981. A large proportion of the region — about 43% in 2018–19 — has no recorded fire history. In 2018–19, less than 1% of the vegetation in this landscape was burnt by bushfire or planned burning while below TFI. This shows that our fire management strategies are carefully considering and planning our burns to reduce our impacts on vegetation below minimum TFI.
TFI status of vegetation on public land, Loddon Mallee region, 1980–2019
The figure below shows the growth stage structure (GSS) status of vegetation on public land in the Loddon Mallee region since 1980.
The figure shows the proportion of the landscape in the juvenile and adolescent growth stages in 2018–19 was 13%, which is a small reduction of about 1% compared to the previous year. The proportion of the landscape in the mature and old growth stages in 2018-19 was 44%, which is a small increase of about 1% compared to the previous year. Significantly, this includes an increase of 2% in the proportion of vegetation in the old growth stage to bring the total to 5%; this is the largest proportion in the old growth stage in the region since 1980.
To achieve optimal ecosystem resilience in the Mallee land systems, the proportion of mature and old growth stage vegetation combined needs to be approaching 90%.
GSS status of vegetation on public land, Loddon Mallee region, 1980–2019
The TFI and GSS cannot be determined on public land with no recorded fire history.
Activities to reduce bushfire risk
Loddon Mallee region fuel management, 2018–19
Fuel reduction | Hectares |
|---|---|
Area treated by planned burning:
| 5,827 |
Area treated by other fuel management methods | 2,444 |
Total area treated to reduce bushfire risk | 8,271 |
Victorian Bushfire Monitoring Program
During the year, the Loddon Mallee Terrestrial Fauna Survey contributed new data to existing datasets about the effects of fire on reptiles and small mammals, helping make our fire response models for species that inhabit Victoria’s large Mallee parks more robust. We use these models in ecosystem resilience analyses to identify the fire management strategies that best protect biodiversity values, by determining the range of vegetation growth stages that will promote the long-term sustainability of populations of these and other species.
The Big Desert-Wyperfeld program, which comprises a network of 125 pitfall sites, aims to find out how species use habitats in different vegetation types of different fire ages. We expect to reduce fuel at these sites at some stage, and the program looks at how quickly habitat and resources return under varying environmental conditions, and how they change over time. The program will gather information we can use for strategic fire planning and habitat management in the short term — over the next three years — and longer term — 10 years and longer.
In 2018–19, DELWP regional staff partnered with Mallee fire district staff, Parks Victoria and wildlife experts to undertake pitfall trapping, floristic assessments and vegetation structure surveys at 27 of the 125 pitfall sites. A total of 810 trap-nights — one trap night is one bucket open for one night — yielded 359 individual animal captures, a rate of 0.44 captures per bucket per night, which is broadly comparable to trapping work done here in the last 10 years. The most commonly encountered species were Beaded gecko, Mallee military dragon and Southern spiny-tailed skink, collectively comprising 61% of all captures. Less-frequently encountered species include Pink-nosed worm-lizard, Western pygmy possum, Silky mouse, Burton’s snake-lizard, Michell’s short-tailed snake and Prong-snouted blind snake.
We plan to assess a further 43 sites in 2019–20, which will bring the total number of sites assessed to 70.
Fuel hazard monitoring program 2018–19
In the Murray Goldfields fire district, we completed pre-burn fuel hazard monitoring for nine burns and post-burn monitoring for six burns. We planned other burns but did not deliver them, and we plan to do post-burn monitoring of these burns if we deliver them in 2019–20.
In the Mallee fire district, we completed pre-burn fuel hazard monitoring for nine burns — two new burns and seven burns we rolled over from 2017–18 — and post-burn monitoring for three burns. We will also do postburn monitoring of any burns we roll over from this year to 2019–20.
Page last updated: 23/12/20