One of Australia’s smallest mammals is on the verge of extinction, but you can help

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They weigh about 15 grams, the equivalent of a 50 cent coin. They devour large quantities of insects. And they have real problems.

Our new research has revealed that the critically endangered southern curved-winged bat continues to decline. Its populations are centered on just three “maternity” caves in southeastern South Australia and southwestern Victoria, where the bats give birth and raise their young. At night, mothers leave their young huddled together in a ‘crib’ on the ceiling of the cave while they hunt for moths, including agricultural pest species. These beautiful bats have already lost 90% of the natural vegetation in their range due to land clearing. Now they face a drying climate.

Our research tracked thousands of these bats and found that new mother bats and their young did not survive well, especially in drought conditions. Our modeling shows that they will be almost extinct within 36 years, with declines of up to 97%. It’s just three generations of bats.

To stop them from trailing other species to extinction, these bats need urgent action.

These bats are sensitive to disturbance and have a limited range.
Emmi van Harten, Author provided

Why are these bats having so much trouble?

Most cave-roosting bats are highly endangered in Australia, with 62% of species listed as threatened at state or national level.

Although we don’t see them often, bats make up a quarter of all Australian mammal species. They play a vital role in our ecosystems, with microbats like the southern curved-winged bat feeding on insects, including agricultural pests. Fruit bats like flying foxes are important long-distance pollinators and seed dispersers. Despite this, Australian bats are understudied and underfunded for research and conservation.



Read more: Endangered Australian bats need protection from a silent killer: white nose syndrome


Bats themselves don’t make it easy. They can be incredibly difficult to study. While many Australians are familiar with our spectacular flying foxes as they pass by at night, most of our 81 bat species are very small. They are also agile fliers, which makes them difficult to catch. It is particularly difficult to capture the same bats multiple times to study critical aspects of their biology such as survival rates.

With the help of a huge team of volunteers, we have safely tagged nearly 3,000 southern curved-winged bats with small microchips.

The beacons allowed us to detect these bats as they entered and exited a major cave at the Naracoorte Caves in South Australia. Using this approach, we were able to collect millions of detections over a period of three and a half years, without having to catch the same bats over and over again.

So what did we find? We found the lowest adult survival rates among female bats that had just given birth and were nursing young compared to males and non-breeding females. Young bats recently independent of their mothers also had low survival rates.

We used these survival results to model future scenarios for the South Australian population and found projected declines, with steeper declines during droughts. If these rates of decline continue throughout the population, the species will be close to extinction within three generations.

folded wing bat
The southern curved-winged bat in flight.
Steve Bourne, Wikimedia CommonsCC BY

Droughts can have devastating effects on our wildlife, with most of the damage being done to our most endangered species. Worse still, droughts occur against a backdrop of existing threats such as widespread clearing of natural habitats.

As drought and bushfires worsen as the climate changes, they can impact large proportions of remaining habitat for some species. The Black Summer bushfires contributed to the listing of the closely related Eastern Curve-winged Bat as Critically Endangered in Victoria.

These threats pose particular risks to cave bats because their hunting range is limited by the location of suitable caves. Although southern curved-winged bats are highly mobile and can travel more than 70 km between caves in just a few hours, most bats congregate in the three maternity caves for much of the year. This means that food and water must be available around these key sites to sustain populations.

Unfortunately, 90% of the natural vegetation in the southern curved-winged bat’s range has been cleared and most wetlands in the region have either been drained and converted to agricultural land or are drying out in due to a combination of groundwater extraction and climatic drying.

What needs to be done?

The recent extinctions in Australia have shown the need to act quickly. In response to these threats, the southern curved-winged bat now has a national recovery team made up of species experts, researchers, veterinarians, land managers and government agency representatives. , zoos and NGOs. This team is implementing the national recovery plan for this bat with the aim of preventing its extinction and seeing it return to a healthy population.

But we can’t leave everything to this group. We can help this and other endangered bats on these four fronts:

  • take action to help reduce the impacts of climate change, such as worsening droughts, megafires and heat events

  • help community efforts to restore natural landscapes by planting trees and native vegetation and restoring wetlands

  • avoid entering caves known to harbor bats, as the southern curved-winged bat and several other species are very sensitive to disturbance

  • explain why bats are important and need our protection.

This year we had the good news that the eastern barred bandicoot has made a significant recovery, going from being listed as extinct in the wild on the Australian mainland to endangered.

This remarkable result shows that a sustained conservation effort can bring even species back from the brink of extinction. We can do the same for the southern curved-winged bat.



Read more: Australia’s next government must tackle our ecosystem collapse and extinction crisis


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