First published December 10, 2020.
Yes, pygmy possums survived the 2019–20 fires on Kangaroo Island. In late 2020, ecologists from the conservation group Kangaroo Island Land for Wildlife recorded live pygmy possums, including the little pygmy possum (Cercartetus lepidus), the smallest possum in the world, while surveying patches of forest that had escaped the flames. It was welcome news after months in which nobody had seen the species and many feared the island population had been lost. A handful of sightings is not a full recovery, though, and the find mainly shows how much depends on the unburnt pockets that remain.
The fires that changed Kangaroo Island
Kangaroo Island, off the coast of South Australia, is Australia's third-largest island and a refuge for wildlife that has declined on the mainland. In late December 2019 and January 2020, bushfires that began in and around Flinders Chase National Park swept across the island's western end. By early January about 170,000 hectares had burned, around a third of the island, and later estimates put the total close to half. Two people were killed on the island.
Nationally, the 2019–20 "Black Summer" fires burned about 24 million hectares. A study commissioned by WWF-Australia and reported in July 2020 estimated that close to three billion native animals, most of them reptiles, were killed or displaced. You may see claims that the fires burned "half of Australia". That is not right: the burnt area was large, but it was a small share of the continent. On Kangaroo Island, however, the loss really was on that scale, and it hit the old, unburnt bushland that many small mammals need.
Meet the little pygmy possum
The little pygmy possum is a tiny marsupial with large ears, big dark eyes and long whiskers. Adults have a head and body of about 6.5 to 7.5 cm, plus a tail of similar length, and weigh roughly 7 to 10 grams, about the weight of a couple of sugar cubes. It is often described as the world's smallest possum.
- Where it lives: Tasmania, Kangaroo Island and pockets of mallee country in South Australia and Victoria. Living animals were first confirmed on Kangaroo Island in 1964.
- What it eats: insects, spiders, small lizards, and nectar and pollen from plants such as banksias and eucalypts.
- How it copes with cold: in cool weather it can drop into torpor, a short hibernation-like state in which its body temperature falls and its oxygen use drops to about one percent of normal.
Kangaroo Island also has a second, slightly larger species, the western pygmy possum (Cercartetus concinnus). The two can look similar in photos, so field teams check details such as teeth to be sure which one they have caught.
How the possums were found
After the fires, Kangaroo Island Land for Wildlife worked with landholders to survey the bush that was left, looking for any sign of species that had not been seen since the fires. Fauna ecologist Pat Hodgens explained that the little pygmy possum was rare on the island even before the fires: "There's only really been 113 formal records of the species." That figure refers to documented sightings over the years, not a population count.
The surveys found the possums in unburnt vegetation, alongside more than 20 other species, including a tammar wallaby and a southern brown bandicoot. Hodgens described such places as "the last refuge for a lot of these species" that depend on long-unburnt, old vegetation.
The photos from the survey
The group shared its finds on Facebook. The posts below come from Kangaroo Island Land for Wildlife.
A Pygmy possum species, yet to determine if it’s a Little Pygmy or a more common Western Pygmy, we will analyse the molar photos to positively identify
Posted by Kangaroo Island Land for Wildlife on Wednesday, 28 October 2020
28 October 2020. The first post shows a pygmy possum that the team could not yet identify with certainty. As the caption explains, little and western pygmy possums can look alike, so the ecologists planned to examine photos of its molar teeth to confirm the species. This kind of careful identification matters, because records feed into official assessments of how threatened a species is.
Little pygmy possum
Posted by Kangaroo Island Land for Wildlife on Friday, 4 December 2020
4 December 2020. A confirmed little pygmy possum. Notice the very large ears and whiskers, which help this nocturnal animal find insects and navigate in the dark among shrubs and leaf litter.
Left Western pygmy possum, right Little pygmy possum
Posted by Kangaroo Island Land for Wildlife on Friday, 4 December 2020
Side by side. This comparison shows a western pygmy possum on the left and a little pygmy possum on the right. The western species is typically a little larger, and seeing both survivors together showed that more than one kind of pygmy possum had made it through in the remaining habitat.
Little pygmy possum
Posted by Kangaroo Island Land for Wildlife on Friday, 4 December 2020
Held in the hand. Animals like this are handled briefly by trained ecologists to record species, sex, weight and condition, then released where they were found. The photos also give a sense of scale: the whole animal is smaller than a human palm.
Little pygmy possum
Posted by Kangaroo Island Land for Wildlife on Friday, 4 December 2020
Another survivor. Each extra individual recorded helps researchers map which patches still hold possums, which is the first step in protecting those areas from future fires and from predators such as feral cats.
What a rediscovery does and does not tell us
Finding a species again after a disaster is good news, but it answers only one question: it is still there. It does not tell us how many animals survived, whether they are breeding successfully, or whether the remaining habitat is large enough to sustain them.
Recovery depends on several things:
- Unburnt refuges. Patches of old vegetation act as lifeboats from which animals can recolonise burnt areas as plants grow back.
- Predator control. Fire strips away cover, making small mammals easy prey for feral cats. Cat control has been a major part of post-fire work on the island.
- Fire management. Another large fire before the bush recovers could wipe out the surviving pockets.
- Repeated monitoring. Surveys over several years are needed to see whether numbers are stable, growing or slowly falling.
How people can help
Most of us cannot survey possums on Kangaroo Island, but there are practical ways to support recovery. Donations to established local conservation groups fund surveys, nest boxes and predator control. Visitors to the island can stay on tracks, follow fire restrictions and report wildlife sightings to local groups. And anywhere in Australia, keeping pet cats indoors at night protects small native animals like pygmy possums.
Sources: Kangaroo Island Land for Wildlife (Facebook); My Modern Met (Pat Hodgens quotes); Wikipedia: Little pygmy possum; Wikipedia: 2019–20 Australian bushfire season. Photos in the embedded posts: Kangaroo Island Land for Wildlife.
COMMENTS