Bushfires in NSW

Topic 3
Impacts of bushfires on
the natural environment

STAGE 3 TEACHER RESOURCE
Years 5-6

An aerial image of a mountain pygmy possum habitat after a bushfire in a national park. Credit: John Spencer/DPIE

NSW National Parks firefighters conduct strategic hazard reduction burns each year to reduce the impacts of bushfires

Bushfires are an essential part of the Australian natural environment. The ‘natural environment’ relates to all living and non-living things that occur naturally on the earth (not made by people).

In this topic, students discover different ways the natural environment has adapted to bushfire over thousands of years. Students also learn about ‘abnormal’ bushfire conditions – more intense and more frequent in more places – and the effect these have on plants, animals, ecosystems and all parts of the natural environment.

At the end of this topic, students will be able to:

describe impacts of bushfires on plants, animals and ecosystems
give examples of ways the natural environment has adapted to bushfire conditions
explain the difference between normal bushfire conditions and abnormal bushfire conditions.

Impacts on plants

In a 2021 study by the CSIRO, Australia's national science agency, researchers investigated the bushfire recovery traits of more than 200 plant species. They found that almost all of these plants had adaptations to survive bushfires, both physical and behavioural. Physical adaptations included specific structural features of the plant to help protect them against the heat. Behavioural adaptations included changes to where plants grew in response to bushfires.

Physical and behavioural adaptations happen over many years of exposure to bushfires. It’s important to note different plant species have different adaptations, but there are some commonalities between them. Some examples include burnt plants re-sprouting from structures below ground, which are unaffected by bushfires above ground. While other plants have developed protection in the form of a thick bark or woody seed capsules.

Click on the image of the Banksia in this section to discover other behavioural and physical plant adaptations that help plants survive the normal cycles of bushfires.

Banksia will often drop their seeds after fire and are some of the first seedlings to emerge after a bushfire

Factors affecting the impacts of bushfires on plants

When looking at bushfire-adapted plants, it’s important to remember there are limits to how much fire an individual plant can handle. While many native plants have developed strategies to cope with normal cycles of bushfires, if these bushfire events become more frequent, plants struggle to survive. This is because they don’t have enough time between significant bushfires to regenerate, and they can’t move locations to escape. It can also be because intense bushfires clear a huge area of land that allows invasive, non-native species to move in and take over.

The place where a plant grows directly affects whether it will have exposure to bushfires and the impacts a bushfire might have on it. For example, plants growing in an alpine environment are unlikely to experience many bushfires. This is because alpine environments are at high altitudes with less oxygen in the air and cooler temperatures. Whereas plants growing in grassland and forest environments are likely to have experienced many bushfires. Grassland and forest environments often have perfect conditions for bushfires: high amounts of fuel to burn, warmer temperatures and high levels of oxygen in the air.

Did you know?

A special team helped protect the ancient Wollemi pine during the Black Summer

During extreme bushfires, there is sometimes a need for human help to make sure culturally or biologically important plants don’t become extinct.

This is exactly what happened during the 2019/20 bushfire season. With fewer than 100 trees left in the wild, a team of specialist firefighters was deployed to protect the Wollemi pine, or ‘dinosaur tree’. With a lineage dating back 91 million years, Wollemi pines were thought to have gone extinct 2 million years ago until a small grove was discovered by a NSW National Parks ranger about 30 years ago.

Read more about the ways NSW National Parks protects the natural environment during bushfire events in the case study in Topic 7.

Impacts on animals

As with plants, native animals have developed a range of physical and behavioural adaptations to cope with bushfire events. Yet animals have a significant advantage in that many can physically move away from bushfires (unless they have an injury that prevents them from doing so), unlike plants.

Mobile animals escape to unburned areas, dams and creek lines. Sometimes they will go back on themselves, actually crossing the front of the bushfire they were fleeing from to find safety in areas already burned. This action can help keep population numbers healthy.

Insects, reptiles and small mammals may hide underground, taking refuge from the flames in wombat burrows or in the hollows of trees with thick, protective bark.

Animals that live in trees tend to be less impacted by bushfires because they can easily move higher up the trees or fly away. However, in extreme bushfire conditions, even the tops of trees burn and this can be devastating.

Find out more of the ways animals have adapted to bushfires by clicking on the image of the brush-tailed rock-wallaby in this section.

A brush-tailed Rock-wallaby sitting on a rock in a national park. Credit: John Spencer/DPIE

Brush-tailed rock-wallabies can run away from bushfires to protect themselves

Factors affecting the impacts of bushfires on animals

Some animals haven’t experienced bushfires before, because they live in areas where they don’t usually occur. It takes abnormal bushfire conditions, where bushfires become so intense they break through containment lines and create their own weather systems, to reach these areas.

Animals living in these areas can get quite confused by bushfires, not knowing what makes a safe haven from the flames. They might also overlook cues indicating the presence of feral animals such as red foxes or feral cats. This might encourage an animal to stay in place when they should actually flee to safer ground, and vice versa.

The hours, days and weeks after a bushfire event bring additional challenges for animals lucky enough to survive the fire itself. Food resources are scarce, water is difficult to access and a burnt landscape makes smaller animals more visible to hungry predators. It is also quite likely their habitat has been destroyed or severely damaged by the bushfire.

These impacts can be devastating for all animals, but particularly those species already classified as ‘threatened’ or ‘vulnerable’. We may lose them forever.

Impacts on ecosystems

Australian ecosystems have found ways to cope with bushfires over time

Many of Australia's ecosystems have been influenced by bushfires, due to both natural processes and through human intervention.

As with plants and animals that inhabit them, many ecosystems and habitats in Australia are adapted to bushfire conditions. Bushfires are part of their natural cycle of change. For example, bushfires can change the structure of soil and release nutrients that promote plant growth. This can then become food for animals in the ecosystem, while other food sources are temporarily unavailable.

Early Indigenous tribes would deliberately burn some areas of land regularly and other areas less regularly as a way to maintain food resources, encourage movement of animals and honour cultural obligations.

Factors affecting the impacts of bushfires on ecosystems

Ecosystems are fragile. With so many interconnected components, changing just one can change the whole ecosystem.

This is something we are starting to see, now that bushfires are becoming more intense and more frequent. Ecosystems are not adapted to these abnormal bushfire conditions, where intense bushfires burn plants beyond the usual point of regeneration or destroy them altogether. When this happens, the positive impacts of bushfires can’t take place and this negatively impacts other parts of the ecosystem.

Really intense bushfires also mean animals can’t escape as easily, and if they can’t escape or find suitable shelter, they will die. This is particularly distressing when they are already identified as ‘threatened’ or ‘vulnerable’ as we may lose the species altogether.

Sometimes, human help is needed to reduce the impacts of bushfires on ecosystems. NSW National Parks staff prepare carrots and sweet potatoes to be dropped by helicopter.

Echidna in front of a burnt tree. Credit: Shari May/DPIE

Echidnas are known to seek shelter underground during a bushfire events

These impacts take years to recover from, and in the meantime non-native species may move in and take over an area. This can also impact ecosystems and habitats, with the potential to change the balance of the natural cycle forever.

The road to recovery depends on many factors, including: