Background
A long history of fire has shaped plant composition and function in many ecosystems globally. These ecosystems typically require a particular fire regime — characterised by intensity, frequency, type, season and spatial properties of fire — to maintain biodiversity.
Despite this relationship between fire and biodiversity, thousands of plant and animal species are now threatened from changing fire regimes, driven by climate change, inappropriate management habitat loss and fragmentation and invasive plants. Invasive plants often change fuel properties (e.g. increased biomass) which can increase fire frequency and/or intensity, resulting in further invasion. In some ecosystems, this type of positive feedback has caused an irreversible state shift, preventing the recovery of native vegetation.
Effective fire management is key to addressing this problem but this is more complex than simply re-instating a historical fire regime. Heavily invaded ecosystems might require a specific initial management regime (e.g. more frequent burning) to re-establish native plant communities and increase their resilience to invasion.
Scientific studies and the experience of Indigenous peoples suggests that where fire management is re-starting after a long period, more-frequent burns can help “re-set” native ecosystems. Repeated burning could also prevent weeds from returning.
Many Australian native species are fire-adapted, so benefit from fire for reproduction or growth, but this is not the case for many of our most prevalent weed species, indicating that more-frequent burning could help get them under control. This is the crux of our planned experiment: to show how 5 to 10 years of more-frequent burning (every 2 years) might improve ecosystem health and weed control across the HV property, compared with typical burning regimes (every 4 to 6 years) or no burning at all (control).
Aims
We aim to establish an evidence-based management framework for grassy woodlands of southeast Queensland, by evaluating how variation in fire frequency affects the composition and function of native plant communities. Implementing fire in an experimental context will have direct, measurable biodiversity outcomes, while developing environmentally– and operationally–sustainable solutions and botanical resources for Hidden Vale’s educational programs.
Our work will show what the best policy is, not only for HV but for properties like it around Australia—increasing our impact and improving conservation efforts much more broadly. Ultimately, our aim is to help HV set the bar for habitat restoration, not just in Queensland, but across eastern Australia.
Methodology
Nine replicate blocks across the non-grazing areaof HV. Each block consists of five plots: 2 x control, 1 x annual burn, 1 x two yearly burn and 1 x four yearly burn, giving 45 plots across the study.
Within each plot in each block, multiple transects will be established to survey plant communities. We considered the topography when allocating burn treatments, to avoid confounding burn treatment with topographic position.
The two yearly and four yearly burn treatments were placed alternately north and south within blocks, so there would be an approximately even number of high and low elevation sites for each burn treatment across the study.
Annual burn treatments were placed consistently between the two and four yearly treatments to maximise operational efficiency. These form part of the two and four yearly treatments and only need to be separately burnt when the other areas are not on the burn schedule.
Expected Outcomes
The project will result in
- New spatial maps of grassy woodland composition and fuel loads.
- Scientifically-informed knowledge of optimal fire frequencies for plant biodiversity.
- A compilation of botanical knowledge to inform ongoing education and research into fire management for biodiversity conservation.