The ecology of Australia’s bushfires: building from the bottom-up

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Elle Lindsay
Writer

Elle Lindsay looks at the lasting impacts of the bushfires in New South Wales.

In the midst of our winter, we have never been more aware of Australia’s summer. Since September 2019, the bushfires have dominated the global news. A fire can cause complete destruction: we have seen it devastate both man-made and natural structures. It takes lives, and though many materials may fuel it, only water and carbon dioxide can truly combat it. Australia is no stranger to bushfires – between 1967 and 2013, it is estimated that they have cost the country AUS$4.7bn. Australia’s environment and climate means the threat of large fires is always present: large areas of grassland and bushland propagate the flames when conditions are hot and dry. Drought and higher than average temperatures made 2019 Australia’s hottest and driest year on record. The resulting drier fuel load partnered with fast-blowing winds have made the fires more intense and less manageable.

Though the fires have affected all six of Australia’s states, the south-eastern state of New South Wales seems to be suffering disproportionately. As senior figures advise mass-evacuation, people across south-eastern Australia are having to choose whether or not to abandon their homes and livelihoods in order to stay ahead of the fires. The unpredictable nature of this natural phenomenon means it can be difficult to know where will be affected or how quickly fires will spread. This is made even more complicated when two or more large fires meet and combine. A national effort to contain the damage, reduce the flames and save stranded individuals has displayed the determination and bravery of affected communities. At this stage, the death toll and numbers of homes and businesses being lost are assessed each day, producing harrowing figures. In contrast, it has been impossible to accurately determine the impact of recent events on the region’s wildlife. Many affected by this nightmare have begun discussing how they plan to rebuild their lives once the fires cease, but what of Australia’s natural world after suffering from such brutal burning?

In primary school we learn about food chains: how herbivores eat plants, carnivores eat herbivores and the biggest animals in an environment eat the smaller ones. As we grow, so too does our understanding, and we come to realise that the reality is much more complex. We discover that a food chain is in fact a simplified way of beginning to describe an intricate web of interconnections between all plants, animals and non-biological aspects of an environment. Yes, animals rely on both plants and one another for food, but other variables, including water, soil, and microbes, have equally important roles within a healthy ecosystem. This web creates the ecological niches in which living things exist – they thrive when a niche contains enough resources, but are stopped from proliferating excessively by resource limitations and predation. This cycle largely balances ecosystems, making the environment resilient enough to cope with minor disruptions; however, major disturbances can have significant impacts. 

It is true that due to the long history of bushfires across Australia, areas of the country’s landscape have evolved to cope with fire. The “survival of the fittest” aspect of evolution has created some extraordinarily resilient plants – for example, many species of native Saltbush are fire resistant and will not burn even when faced with continued flame. Numerous species rely upon fire to regenerate and as a result, controlled burning has often been used in ecosystem management, not least by indigenous communities. Though this means that Australia is certainly better adapted to cope with large-scale fires than most other countries would be, it is undeniable that these fires will have severe consequences for the natural environment. With over 10.3m hectares (larger than the area of Scotland) having been scorched, much wildlife will have been displaced alongside the humans. More mobile animals might have a chance of fleeing the danger unaided, but there is no guarantee that they would be able to locate a safer environment or to recreate their niche elsewhere. Meanwhile, the vast majority of species have no hope, and many will be wiped out across the affected regions. As the realisation hits that the country contains over 240 species that are not found anywhere else in the world, the extreme loss of animal life begins to trouble people. Many will try to protect what they can, but the scale of this disaster renders the fight futile. As brave volunteers and firefighters try to contain blazes and save lives, the country knows that its only hope is for rain to put an end to their suffering. 

It will be years before the level of damage can be fully understood. Experts have tried to assign numbers to summarise the impact, but there is no real consensus and as the fires continue to rage, assessments of losses will continue to be underestimates. One thing that is clear is that wildlife not adapted for fire will continue to suffer; the ecosystem’s web has been entirely untangled and will need to be re-established from the bottom-up. Long after the flames have ceased, the natural environment will carry the burden of their presence – understandably there will be a loss of key habitats, but there are direct impacts which are harder to quantify, such as soil infertility, smoke damage and water contamination. The aforementioned niches will no longer exist. Carnivores predate upon large, grazing mammals such as kangaroos, which in turn rely on plants in semi-arid plains and grasslands. These plants require the right balance of nutrients, uncontaminated water and beneficial microbial species to thrive. Long before a climax community filled with all the recognisable species of trees and mammals can occur, the balance of abiotic factors needs to be restored – from soil pH to the correct abundance of microbial species. The environment must literally rise from the ashes, starting from the ground-up. 

In the end, recovery time depends upon the diversity of the climax community, or the “end goal”, but the legacy of these fires in the wild will live on long after the man-made structures have been rebuilt.

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