Nature’s way to reduce fire risk

Thursday, December 1, 2016

All gardeners know that turning and aerating a compost pile decomposes it far more quickly. The resulting rich humus is a soil conditioner, encourages good fungi and invertebrates, holds water and provides nutrients to the garden.

This is a simple example of how our forests function when the many players are healthy and in balance.
The Superb Lyrebird is one of these essential components of forest fuel reduction. Using its strong legs and long toes, this two-legged compost maker can rake through tonnes of leaf litter a year.

It turns over dead leaves, twigs and bark while looking for a meal.

The soil is rich, sweet and damp where there are healthy populations of lyrebirds. There is very little ground fuel, instead a deep layer of humus protects the soil, feeds plant life and provides habitat for micro invertebrates and others at the base of the food chain.

There are many other members of the understorey composting crew, including the diggers and scratchers such as echidnas, bandicoots and potoroos.

They help manage the soil and humus layer by mixing the ‘compost’.

The fungi-seeking mammals dig and eat michorizal (underground) fungi, then process and disperse the fungi spore across the forest in handy fertiliser pellets. The fungi grow in association with plant roots, exchanging essential nutrients important for their health.

Other small forest gardeners who break down dead plant material include myriad colourful fungi, mosses, termites, wood-eating beetles, grubs and even moth larvae that consume dead  eucalypt leaves. In unison, this team of volunteers can clear large areas of ground litter and even devour whole logs. Who has broken open a dead log and found its soft damp innards teeming with life?

This brilliant system has for millennium maintained natural  fire-reducing, healthy soils, diverse habitat and a rich food chain for birds, mammals, amphibians and reptiles.

The lyrebird is a wonderful ambassador which encapsulates this system. The Malleefowl is its western counterpart. These birds mix litter and soil to speed up decomposition. They prefer unburnt areas where there is a smorgasbord of food to scratch for and vegetation cover from predators.

Research by Dr Steve Leonard of LaTrobe University has shown that after a fire that can kill lyrebirds, there is mass regeneration of vegetation.

This thick regrowth makes it difficult for any surviving lyrebirds to forage through and turn the soil. Depending on the forest, this could begin a terrible feedback loop for fire.

Leonard and his colleagues excluded lyrebirds from a number of plots for nine months then measured the fuel loads. When comparing these plots to adjoining areas where lyrebirds were active, there was on average 1.6 tonnes per hectare less fuel with a maximum difference of 7.5 tonnes per hectare. So on average, there were 25% lower fuel loads in lyrebird areas.

When this data was entered into a fire behaviour model, it showed that lyrebird activity could exclude a fire in low to moderate fire weather conditions. But in more dangerous weather conditions, the models predicted lower rates of spread with lower flame height and a less intense fire.

Sadly, lyrebirds and their volunteer cohorts are often killed off, displaced or left without cover to be preyed on by foxes and cats after government planned burns. Larger burns, which can cover thousands of hectares, could be effectively wiping out critical components of natural fuel reduction systems that could take decades to return. Both the vegetation and the complex ecosystem can be changed dramatically as a result of inappropriate fire regimes.

The vicious cycle of regular planned burns and the eradication of many flora and fauna groupings has not been considered with past burn plans.

The new ‘risk-based approach’ seems to equally disregard the impacts on the environment.

Public concern has been growing over the loss of native wildlife and other values as a result of inappropriate burns. The worst examples can be more destructive than a natural fire.
These inappropriate burns are now being seen as counterproductive and many simply provide a political placebo, giving the public a false sense of security. The effectiveness has been shown to be minimal to nil in many instances but comes at a great cost to lyrebirds, ground and arboreal mammals, myriad invertebrates, reptiles and the flowering plants and nesting birds in spring.
The new ‘risk-based’ approach appears to have not reduced the hectares planned for burning nor seriously incorporated ecological or scientific information. This review of hectare-based burn  targets was a lost opportunity to understand and enlist our natural bio-digesters that have been on the job for thousands of years.

Government fire agencies could make huge savings, reduce fire risk and maintain healthy public lands by protecting and teaming up with the natural populations of the Superb Lyrebird and Malleefowl to manage our forests.

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