Pacific sheath-tailed bat Photo: Supplied
Finding the endangered Pacific sheath-tailed bat requires a good eye, torches and a lack of phobias, says Isaac Rounds, terrestrial protected area manager with Conservation International in Fiji.
The largest known cave roost of bats in the Pacific region was discovered on the island of Vanua Balavu on the remote Lau archipelago.
Round said people living in a nearby village with knowledge of the caves helped the team find the bats.
"You need to be comfortable going through caves and not have phobias," he said.
"You need good torches, and some good climbing skills to get into some of these difficult to access caves."
Rounds said typically roosts are in the hundreds, but this one was home to between 2000 and 3000 bats.
The previous biggest find was in 2018 in Taveuni island in Fiji where about 2000 bats were found, but this number dwindled to only a couple of hundred in 2019.
The Pacific sheath-tailed bats are small brown bats weighing about 6 grams and have had a rapid global decline.
They are classified endangered under the International Union for Conservation of Nature red list of threatened species and are listed as one of the 35 species on Bat Conservation International's worldwide priority list for conservation.
The species was previously found in Tonga, Samoa, American Samoa, and Vanuatu.
Rounds said the decline was partially down to habit destruction.
"A lot of the areas where they were once found in large numbers were once large forests, and those forests are no longer there."
Other causes of the bats decline are from invasive species like cats entering the caves, Rounds said.
"They also have one or two pups in a year, so the recruitment is very slow."
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A 'remarkable insight'
The discovery was led by Conservation International in Fiji, with the help of the Australian Museum and the University of Adelaide, in April.
The mission was led by chief scientist and director of the Australian Museum Research Institute, Professor Kristofer Helgen.
"We have found what we now believe is the biggest population and roost for this species in Fiji and the region," Helgen said.
"The size of the roost found, numbering in thousands, gives us a remarkable insight into the potential population size and distribution of the bats, which may be larger and more spread out than previously thought."
Helgen said this and other discoveries of the bat roosts on the island provided "new hope" for the conservation efforts of the species.
"The virtual extinction from other regions of the Pacific makes this new roost in Fiji a monumental find and the most important stronghold for the species' conservation in the region," he said.
Helgen said Pacific Sheath-tailed bats were "ecosystem superheroes" helping maintain ecological balance.
"In essence, their survival is not just about them, but the health, prosperity, and balance of the world we share."
University of Adelaide Associate Professor, Wayne Boardman, who was part of the mission, described the discovery as a "career highlight."
"While this is the biggest population of the species in the Pacific which has been discovered to date, it is still not enough to remove the species from the endangered list," said Dr Boardman.
"It just gives us more hope that the population is in a slightly healthier position than it was before and all the more important to protect it."