- Researchers have described three new gecko species in northwestern Cambodia’s limestone hills and are eager to conduct further research, but recent border clashes with Thailand have disrupted their studies.
- The region’s limestone karst landscape is a biodiversity hotspot that could harbor many species yet unknown to science.
- These areas are also threatened by the growing demand for cement, made from limestone.
Researchers have described three new gecko species in northwestern Cambodia’s limestone hills and are eager to conduct further research, but recent border clashes with Thailand have disrupted their studies.
Violent clashes this summer, which killed close to 40 people and displaced nearly 300,000 across the two Southeast Asian nations, cut follow-up field surveys short, researchers told Mongabay. The dispute has indefinitely delayed exploration of the landscape, which may host an abundance of creatures yet to be described by science.
Pablo Sinovas, Cambodia country director for Fauna & Flora, an international NGO, was leading the surveys in Battambang province near the Thai border in late July when the fighting erupted. He told Mongabay in August that the decision to pull back was taken as a precaution after Thai fighter jets bombed Cambodia.
“In Cambodia, systematic exploration [of karst landscapes] has only just begun,” Sinovas said. “We can expect many more [species] discoveries to be made. These findings highlight the extraordinary diversity that can be hidden in karst ecosystems.”
When the clash broke out, the research team pivoted to surveying karst towers near where they had found the Kamping Poi bent-toed gecko (Cyrtodactylus kampingpoiensis), Battambang leaf-toed gecko (Dixonius noctivagus) and Khpoh slender gecko (Hemiphyllodactylus khpoh) in 2024.
The discoveries of these species, announced in three studies published in 2025, had thrilled these conservationists and made them eager to double down on karst research.
“Think of these isolated limestone formations as islands. Each island is its own little vignette of biodiversity, where nature replays the experiment of adaptation and natural selection over and over,” Lee Grismer, lead author of the studies that described the leaf-toed and slender gecko, told Mongabay. “We go to these natural insular laboratories to find the results of nature’s experiments.”
The border clash is just one of a torrent of threats bearing down on these Cambodian karst ecosystems, which Grismer called “somewhat of a black hole as far as scientific research goes.”
Dwindling funds for global conservation, border tensions and Southeast Asia’s insatiable demand for cement — often made from limestone found in karst landscapes — are all putting pressure on future research.
‘Karst is being grinded down’
Karst is a type of topography underlain by limestone, often featuring caves and rock structures, which are usually biodiversity hotspots because of their disconnected nature.
Researchers refer to these landscapes as “karstic archipelagoes” since erosion, farms and water diversion often separate limestone hills from one another like islands in the sea.
Evan Quah, lead author of the bent-toed gecko study, told Mongabay he was “blown away by the amount of karst that had not been surveyed” in Cambodia. “Just within Battambang and neighboring provinces,” he said, “there are dozens of karst towers that we can see but we have not yet been able to get to.”
After pulling back from the border, the field team was able to survey other karst areas. Quah said that while they “still need to go back to the lab to start analyzing the data and looking at the specimens,” he’s “pretty confident” they have more new species and country records — when a species is found in a country for the first time — in hand.
Quah, an associate professor at University Malaysia Sabah, said he hopes the research team can return to the border next year — before the region’s development boom reaches more karst towers.
“The main challenge facing karst is our insatiable demand for cement,” said Quah, who has helped describe more than 50 species of amphibians and reptiles across Southeast Asia. “For progress and development, humans are continuously building around the globe, which means there is a never-ending need for cement.”
In order to produce enough cement, “karst is being grinded down” in countries like Cambodia, he said. This represents the “biggest challenge to these ecosystems since a lot of Southeast Asia’s karst is in Indochina.”
This could lead to animals going extinct before humans even know they exist, Sinovas said.
“Many karst endemic species have extremely restricted ranges. The destruction of a single limestone hill can lead to the extinction of potentially multiple species,” Sinovas said. “It is critical and urgent that we protect these sites. Otherwise, we risk species vanishing literally into cement.”
Fauna & Flora in Cambodia is working to secure protected area status for two individual karst towers.
“The documentation of new species is an important step to highlight the uniqueness of some of these formations,” Sinovas said. “It is a way to help catalyze interest for the conservation of these areas.”
Sothearen Thi, karst biodiversity coordinator for Fauna & Flora in Cambodia, told Mongabay that the priority is to get the karst hills of Phnom Sampov and Phnom Banan in Battambang classified as “natural heritage sites.”
“It is just the first step. We can continue later with other karst hills across the border,” Sothearen Thi said, adding that the Ministry of Environment and Battambang provincial government were in the process of drafting a subdecree for the two sites. “Through biodiversity surveys, we can provide the baseline data for legally protecting these areas.”
DNA-laden cement
Grismer, who is also director of research and a professor of biology at La Sierra University in California, said, “the economic rewards from cement are very difficult to pass up for under developed nations. It is a shit ton of money.”
“A lot of our sidewalks, the cement in our houses and our freeways are loaded with the DNA of all sorts of species that may have never been to known to exist,” Grismer said. “This is a catastrophic slap in the face to biodiversity.”
While last year’s surveys were “extremely successful,” more species surely remain undocumented in the area, he said. Given the limited distribution and likely endemic nature of the three species found in 2024, the geckos will likely meet the IUCN’s “critically endangered” criteria.
Grismer underlined the importance of field surveys in these isolated karst towers by explaining that these baselines form a “historical trajectory of how different species have evolved over time.” Researchers can then “relate that back to the environment and identify what causes this kind of change and what causes that type of change,” he said.
“From that, we can make predictions as to how they are going to evolve in the future,” Grismer said. “This gives us a hedge against perhaps how to mitigate some of the possible ecological problems that are going to arise with climate change.”
He continued, “There is probably nothing more important than conserving the biodiversity of this planet because without biodiversity, humans wouldn’t exist.”
Banner image:A Battambang leaf-toed gecko (Dixonius noctivagus). Image by Hun Seiha with Fauna & Flora Cambodia.
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Citations:
Quah, E. S., Grismer, L. L., Sinovas, P., Chourn, P., Chhin, S., Hun, S., … Grismer, J. L. (2025). Geographically structured genetic and morphological variation in a new species of Cyrtodactylus (Squamata, Gekkonidae) from a karstic archipelago in western Cambodia. ZooKeys, 1240, 73-115. doi:10.3897/zookeys.1240.139691
Grismer, L.L., Sinovas, P., Quah, E.S., Thi, S. Chourn, P., Chhin, S., … Grismer, J.L. (2025). A new species of Dixonius Bauer, good, & Branch, 1997 (Squamata: Gekkonidae) from a karstic archipelago in western Cambodia. Zootaxa, 5653(4), 501-523. doi:10.11646/zootaxa.5653.4.3
Grismer, L.L., Sinovas, P., Quah, E.S.H., Thi, S., Chourn, P., Chhin, S., Hun, S., Cobos, A., Geissler, P., Ching, C. & Murdoch, M.L. (2025) A new species of lowland karst-dwelling Slender Gecko Hemiphyllodactylus Bleeker, 1860 (Squamata: Gekkonidae) from a karstic archipelago in western Cambodia. Zootaxa, 5569 (2), 253–281. doi:10.11646/zootaxa.5569.2.3
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