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Hayakawa Lab, Group of Ecological Genetics, Section of Environmental Biology, Faculty of Environmental Earth Science, Hokkaido University

Bushfire and Regeneration: Koalas Living with Fire

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July 6, 2020

Monkey 5(1): 18-19 (2020) (Japanese)

News from Kangaroo Island

At the end of the year 2019, news came from Kangaroo Island to Japan. The island is where I performed fieldwork. It is said that a massive bushfire has broken out there. Half of the island was burned. The forest, the beasts, the birds, the bugs, the livestock, and the houses all burned...

Kangaroo Island is a beautiful island in the southern part of Australia. The abundant eucalyptus forest, where koalas and kangaroos live, and the lives of people who do agriculture and fishing coexist. It was that kind of island.


Eucalyptus forest on Kangaroo Island before the fire (March 2017); the 2019-2020 bushfire destroyed this scenic forest. Bunker Hill Lookout, Flinders Chase National Park, Kangaroo Island, South Australia. © Takashi Hayakawa

At the beginning of 2020, the media coverage of Kangaroo Island was disastrous. All of the forests had been burned down and turned into scorched earth covered in ashes, with only blackened branches and trunks. The fires had burned houses and livestock and taken away people's livelihoods. Fire brigades were risking their lives to extinguish the fire. Veterinarians were working hard to help burned and injured animals. I could not stay in Japan.

Kangaroo Island after fire

Bushfire is not uncommon in Australia, which is characterized by hot, dry summers. Oily eucalyptus trees can ignite with a little friction or lightning strike, leading to a fire. Small fires happen every year. This summer, however, was too much of a burn. The heatwave was one of the hottest on record. The fire turned into a catastrophe that spread throughout the forest.

Australia is a country with four seasons like Japan. When summer is over, fall comes, and so does the rain. In March, Kangaroo Island had early fall and the fire was put out. Then, I went to Kangaroo Island to learn the effects of the fire on the ecosystem. We drove to the west of Kangaroo Island, which was the center of the fire. It was a horrible landscape. There was no beautiful, lush forest that I had once known, but the gray ground and charred trees. Blackened white chips were falling everywhere. These were bones of burned wildlife and livestock. The corpse of a koala that had died of starvation was also found.


Three species of plants that put out new leaves from a blackened trunk: Grasstree (yacca: Xanthorrhoea semiplana) that extends its spikes to the sky; One species of eucalyptus (Eucalyptus leucoxylon) with new sprouting buds and epicormic shoots; Dessert banksia (Banksia ornate) with “cones.” © Takashi Hayakawa

Restored eucalyptus forest ecosystem

As I walked through the desperate landscape, watching out for fallen trees, I noticed something. The green is there. Grasstrees sprouted countless elongated leaves on the ashcovered ground. The flowers were also in bloom. The scorched banksia trees had scattered its seeds. From the roots and trunks of the pitchblack eucalyptus trees, many new shoots and leaves were blowing out in unison. What a beautiful green contrast in a grayscale world!

The grasstree leaves and eucalyptus buds had been unnaturally cut off. They are food marks. It must be by western gray kangaroos or Tammar wallabies. Ants were licking the exudate from the cross-section. Some of the grey scorched earth had risen to a light brown. It is a termites' nest. Furthermore, there was a hole in the nest. These are the traces that the lizards opened to build their nests. In just a month or two, the plants had regenerated, providing food and shelter for the animals that had survived the fire. The eucalyptus forest ecosystem, adapted to high temperatures and dryness, can accept frequent fires and change generations quickly. Even if, as in this period, the scale of the bushfire was drastic and catastrophic, the forest was certainly beginning to be restored.


A new mound made by termites (Nasutitermes exitiosus) in the scorched earth. A monitor lizard (goanna: Varanus rosenbergi) is drilling a horizontal hole for a nest. © Takashi Hayakawa

Koalas living with fire

How about koalas living on eucalyptus trees that provide food leaves? Bushfire deprives koalas of places to live and food at the same time. A team of conservation volunteers (RSPCA South Australia) showed me where the survived koalas are. There was a koala in a low, blackened eucalyptus tree. I looked up and saw another few koalas scattered in the nearby trees, clinging to their trunks. By nature, koalas do not make groups. They may have been reluctantly gathered in search of the few eucalyptus trees with new leaves. The low position of the tree is probably because it frequently moves down to the ground in search of limited new leaves. Koalas were also rescued by regenerated eucalyptus trees.


A koala (Phascolarctos cinereus) that has survived the bushfire moves through the eucalyptus trees (Eucalyptus globulus) with blackened trunks in search of new leaves that have begun to blow. © Takashi Hayakawa

There was an unprecedented catastrophe. However, the resilience of the ecosystem created by the eucalyptus forest was also far beyond human imagination. I felt as if nature had spoken to me that there was nothing to worry about. It is said that the large bushfires this quarter are strongly related to global warming. Japan is also experiencing record high temperatures, as it does every year. Koalas' life with fire teaches us a fact that we should never miss the fire on the other side.


Takashi Hayakawa
Assistant Professor, Group of Ecological Genetics, Section of Environmental Biology, Faculty of Environmental Earth Science, Hokkaido University. Adviser, Japan Monkey Centre. He performs a comparative study to reveal why koalas and monkeys live in trees in the same way, even though they live on different continents and have different ancestors. The profile picture is with Kangaroo Island kangaroos (a subspecies of western gray kangaroo, Macropus fuliginosus fuliginosus).


This essay was originally published in a Japanese jounal Monkey (Japan Monkey Centre) on June 1, 2020, and translated by the author (Takashi Hayakawa). The author thanks Dr. Peggy Rismiller and Mike McKelvey for kind advise and discussion.

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