Asia’s oldest, grandest karst landscape
UNESCO has been effusive in its praise for the transboundary heritage site spanning Phong Nha – Ke Bang National Park in Vietnam’s Quang Tri Province and Hin Namno National Park in Laos’s Khammouane Province.
According to the latest UNESCO dossier, these two areas, nestled in the heart of the Annamite Range, form a contiguous geological and biological expanse of nearly 220,000 hectares. This region features the most ancient karst topography in Asia, a limestone labyrinth that began forming during the Paleozoic era over 400 million years ago, serving as exceptional evidence of UNESCO’s criterion for outstanding geological and geomorphological value.
This continuous subterranean world boasts over 220 kilometers of caves and underground rivers. It is home to Vietnam’s Son Doong Cave, the world’s largest by volume, and Laos’s Xe Bang Fai Cave, whose underground river can discharge a staggering 2,880m3 of water per second during the monsoon season. A high density of diverse karst features, including dendritic caves, dry caves, hanging caves, and enclosed dolines, exists in a near-pristine state, creating a landscape of exceptionally rare scientific and aesthetic importance on a global scale.
Nguyen Luong, a conservation expert with Fauna & Flora International (FFI), notes that the area’s rich geological tapestry of intermingled limestone, sandstone, slate, and granite has sculpted a complex geomorphological system. This, he says, offers invaluable case studies for geology, hydrology, biology, and climate change research within this shared heritage site.
Meanwhile, Director Pham Hong Thai of Phong Nha – Ke Bang National Park adds a crucial perspective. “According to UNESCO’s criteria”, he explains, “this area represents a rare example of a large-scale karst ecosystem that is intact, interconnected, and functions naturally. It’s a mosaic where evergreen forests, dry limestone forests, moist dwarf sandstone forests, and rare limestone pine forests all coexist, creating a unique array of habitats for thousands of species.”
Particularly remarkable is the subterranean ecosystem, a sanctuary for troglobites, which are species adapted to permanent life in caves. These include blind fish, pigmentless insects, lichens, algae, and numerous endemic species never recorded anywhere else. The uninterrupted transboundary connection ensures that evolutionary and adaptive processes continue naturally, unfragmented by administrative borders.
“This region is recognized as a global biodiversity hotspot”, he elaborates. “It hosts over 2,700 species of vascular plants, with more than 400 being endemic to the Central Laos-Central Vietnam area. The fauna includes 800 vertebrate species, comprising 154 mammals, 117 reptiles, 58 amphibians, 314 birds, and 170 freshwater fish. The presence of critically rare, endangered, and endemic species like the Hatinh Langur, the Southern white-cheeked gibbon, and unique varieties of orchids, begonias, and cave fish underscores the area’s vital importance for global conservation. With up to 133 globally threatened plant species and 104 animal species, and as a stronghold for at least 38 species endemic to the Annamite Range, it is truly the last refuge for many.”
Forging transboundary sustainability
Both Phong Nha – Ke Bang and Hin Namno are designated national parks. In Vietnam, Phong Nha – Ke Bang was established in 1986, expanded in 2015, and recognized as a Special National Monument in 2009. Across the border, Laos designated Hin Namno a national park in 2020 under its new Forestry Law, and it has earned a coveted spot on the IUCN Green List, a global standard for conservation excellence.
Director Pham Hong Thai reports that the leadership of both parks has developed comprehensive and meticulous joint management plans. These include buffer zone land-use planning and sustainable tourism strategies that limit the number and types of visitors to major caves like Son Doong and Xe Bang Fai.
All activities impacting the ecosystem, from logging to illegal poaching, are strictly monitored. Unifying these two adjacent protected areas into a single transboundary heritage site not only expands the total conservation area but also significantly enhances its ecological integrity, broadening the representation of the diverse landforms and ecosystems within the Annamite Range.
Experts affirm that this transboundary collaboration strengthens the region’s resilience against cross-border threats like deforestation, poaching, and uncontrolled tourism development.
Although risks like forest loss, infrastructure encroachment, and the impacts of mass tourism persist, coordinated bilateral management is setting a new benchmark for conservation cooperation. At the same time, it’s supporting local livelihoods through responsible ecotourism and the sustainable harvesting of forest products.
Dr. Leonid Averyanov of Germany, one of 20 scientists who compiled the heritage dossier, captures the site’s profound significance. “This expansion is a powerful symbol of ASEAN regional cooperation in nature conservation”, he writes. “It contributes not only to global conservation targets but also honors the traditional knowledge and intangible culture of indigenous peoples like the Salang, Bru Van Kieu, May, Ruc, and A rem.”
He concludes, “This partnership helps maintain stability in the border region, asserting a form of soft sovereignty through environmental cooperation, and it lays the groundwork for responsible ecotourism to replace short-sighted exploitation. Most critically, for dozens of species that survive nowhere else on Earth, the transboundary heritage of Phong Nha - Ke Bang and Hin Namno is their last hope for survival. It is, without a doubt, one of Southeast Asia’s final ‘green jewels’ to retain its full ecological integrity and endemic character.”
