- A recent census of cave-dwelling bats in northeastern Myanmar found many karst caverns are increasingly inhospitable for the winged mammals due to human disturbance, posing risks to both bats and people.
- Bats are natural reservoirs for many viruses, researchers say, which means managing the ways humans interact with them is vital to managing potential disease spillover, researchers say.
- The main sources of disturbance are limestone quarrying, tourism and religious activities, hunting of bats for food, and guano harvesting.
- To manage the ecological threats and disease risk, the researchers recommend better conservation protections, improved land-use planning, and dedicated cave management plans that include public education programs on cave hygiene and zoonotic disease risk.
Limestone karst is like an island. Each rocky formation rises distinctly out of the surrounding landscape. Over time, an array of highly specialized species, each adapted to that particular landform’s jagged forests and dark caves, have evolved. As a result, many karst species are endemic and perilously rare.
Myanmar is home to Southeast Asia’s second-largest area of limestone karst, after Indonesia; its rugged peaks cover a total of more than 80,000 square kilometers (31,000 square miles. The area hosts the entire global population of Popa langurs (Trachypithecus popa), one of the world’s most recently described primates, and scores of gecko species described only in the past decade. Scientists say countless others likely remain tucked away in obscurity, waiting to be discovered.
Yet despite its biodiversity, less than 1% of Myanmar’s limestone karst is formally protected, prompting concerns from conservationists about fragile wildlife populations that are facing mounting pressure amid a boom in clandestine mining and deforestation across the country to meet rising demand for cement, minerals and timber.
Now, a recent census of cave-dwelling bats in northeast Myanmar’s Shan state indicates many karst caverns are becoming increasingly inhospitable for the winged mammals due to human disturbance, posing risks to both bats and people.
“Bats are natural reservoirs for many viruses, including coronaviruses,” said Thura Soe Min Htike, conservation officer at the Nature Conservation Society–Myanmar and a co-author of the study. “Understanding how bats interact with their environment, and how humans interact with bats, is an important first step in preventing future disease spillover.
“The real issue is not the bats themselves, but human disruption of their habitats which increases the risk of disease transmission,” Thura said.
A ‘One Health’ approach
The new study, published in Global Ecology and Conservation, examined the interactions between bats and villagers at 41 sites in Pinlaung township, following the internationally recognized “One Health” approach that recognizes human health, animal health and environmental health as interconnected.
Thura and his colleagues used cameras and traditional observation methods to locate and record the bat populations at each site in late 2023. Bats from five evolutionary lineages (genera) were living in the roosts that ranged in size from two individuals to more than 200,000 bats from a variety of species. The team recorded fruit-eating bats from the genus Eonycteris in the caves, as well as insect-eating horseshoe bats (genus Rhinolophus), roundleaf bats (genus Hipposideros), mouse-eared bats (genus Myotis) and trident bats (genus Aselliscus).
After examining a range of environmental conditions at each site and interviewing residents of 24 villages, the researchers concluded that more than 80% of the cave systems are significantly disturbed by humans, with seven assessed as “highly vulnerable” and in need of urgent conservation action.
The main sources of disturbance are limestone quarrying, tourism and religious activities, hunting of bats for food, and harvesting of bat droppings, or guano, for use as fertilizer on local farms.
One particularly concerning find was the high levels of exposure to bat urine and feces reported by people who harvest guano. Overall awareness of the need to wear protective clothing and wash after handling guano is generally low, which the researchers say could potentially raise people’s risk of contracting zoonotic diseases.
To minimize the human health risks and disturbance to sensitive bat roosts, the researchers recommend local authorities draw up dedicated cave management plans and introduce community-based health education programs on zoonotic disease risks and hygiene guidelines for safer guano handling, including consistent use of protective clothing and equipment.
Irreplaceable roosts merit protection
The results also confirmed the importance of Shan state for bats, with many caves providing irreplaceable maternity roost sites for the tiny mammals. Some subterranean vaults in the region extend more than 2.3 kilometers (1.4 miles) and 160 meters (525 feet) deep into the Earth. What’s more, over half of the caverns the team explored had never been scientifically examined before. For Thura, this suggests “there may still be many more undocumented biodiversity hotspots.”
Political instability inflamed by the 2021 military coup meant some potential bat caves were beyond the reach of the researchers. This not only limited their ability to fully assess the region’s importance for bats, but also raised the fear that these inaccessible sites could be destroyed by unchecked mining and deforestation, displacing roosts before they’ve even been studied.
The researchers underscore that bats and their limestone karst roost sites merit improved protection in their own right in Myanmar. Bats play a significant role in ecosystems as seed dispersers and pollinators, boosting the natural regeneration potential of forests. By guzzling insect pests, they’ve also be shown to have measurable economic benefits on agricultural yields.
However, current land-use policies in Myanmar don’t mandate environmental impact assessments before sensitive cave systems are opened up for development or other human use. The researchers say this needs to change, alongside expanding formal designations and protections of key karst ecosystems.
Community involvement key
Thiri Dawei Aung, executive director of the Biodiversity and Nature Conservation Association (BANCA), a Myanmar-based nonprofit working to protect fragile karst ecosystems in the Tanintharyi region, said community involvement is the key to achieving effective protection for both nature and people. “Without full community participation, protection cannot be successful,” she told Mongabay.
BANCA focus on several karst sites experiencing intense development and human pressure, she said. However, Thiri, who wasn’t involved in the new study, said contested jurisdictions between central, local and ethnic governance significantly complicates matters.
“This is why local people are so important to conservation in Myanmar,” she said. Education programs to boost local understanding of the ecological value and crucial role of karsts in human and wildlife well-being have been pivotal in Tanintharyi, she added, galvanizing action toward a karst conservation action plan now being implemented through a community-led committee.
Thura and his team in Shan state are continuing their research in nearby villages to learn more about how rising land-use change affects the interactions between people and wildlife, as well as the prevalence of zoonotic viruses in the environment.
As the political conflict in Myanmar persists, Thura said he’s conscious that biodiversity is a silent victim. “In such contexts, environmental protection often becomes a lower priority,” he said. “However, failing to conserve ecosystems could lead to long-term ecological and public health consequences.”
Banner image: An insectivorous bat photographed in a limestone karst cave in Shan state. Image courtesy of Sa Myo Zaw.
Carolyn Cowan is a staff writer for Mongabay.
Citations:
Clements, R., Sodhi, N. S., Schilthuizen, M., & Ng, P. K. (2006). Limestone karsts of Southeast Asia: Imperiled arks of biodiversity. BioScience, 56(9), 733. doi:10.1641/0006-3568(2006)56[733:LKOSAI]2.0.CO;2
Aung, M. M., Htike, T. S., Phwe, N. P., Aung, O., Aung, P. P., Yae, W. M., … Evans, T. S. (2026). Limestone karst ecology and anthropogenic activities associated with cave-dwelling bats of southern Shan state, Myanmar. Global Ecology and Conservation, e04071. doi:10.1016/j.gecco.2026.e04071
Wanger, T. C., Darras, K., Bumrungsri, S., Tscharntke, T., & Klein, A. (2014). Bat pest control contributes to food security in Thailand. Biological Conservation, 171, 220-223. doi:10.1016/j.biocon.2014.01.030
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