Seven decades without human disturbance created an accidental nature reserve. Endangered red-crowned cranes, leopards, and bears reclaimed the buffer zone, a natural experiment in ecosystem recovery.
A sanctuary born from conflict
The Korean Demilitarized Zone (DMZ) is a paradox. Established by the 1953 armistice agreement, this 250-kilometer (155-mile) long, 4-kilometer (2.5-mile) wide buffer zone is one of the most heavily fortified borders on Earth. It is laced with an estimated one to two million landmines. Yet for over 70 years, the almost complete absence of human activity has allowed nature to reclaim the land, turning a symbol of war into an ecological sanctuary.
This unintended rewilding has created a unique open-air laboratory for scientists. The zone contains several ecosystems, from eastern mountains and forests to western wetlands, rivers, and estuaries. This variety of habitats, compressed into a narrow corridor, supports a high level of biodiversity. Surveys by South Korea’s National Institute of Ecology have identified nearly 6,000 distinct species within the DMZ. This includes 1,926 plant species, 47 mammal species, and 277 bird species. The region is a habitat for 101 endangered species, which is approximately 38% of all endangered species in South Korea.
A refuge for rare species
The DMZ is an important wintering ground for the endangered red-crowned crane (Grus japonensis). With a global population of only a few thousand, the hundreds that migrate to the DMZ's wetlands and agricultural buffer zones are important for the species' survival. Alongside them are white-naped cranes and at least five other crane species.
In October 2018, an unmanned camera installed by ecologists captured the first confirmed photograph of an Asiatic black bear (Ursus thibetanus) inside the DMZ. The juvenile bear, estimated to be eight or nine months old, suggests a breeding population has established itself within the zone's protection, a significant discovery for a species nearly wiped out on the peninsula. Other rare mammals thrive here, including the Siberian musk deer, the long-tailed goral, and otters. While the presence of the critically endangered Amur leopard (Panthera pardus orientalis) is unconfirmed, some reports suggest a few individuals may use the DMZ as part of their territory, crossing from populations in Russia and China. The security cordon and the millions of landmines, while dangerous to humans, have become the animals' most effective protectors.
💡Fun Facts
Estimates suggest between 1 and 2 million landmines are still buried in the DMZ, with some areas having a density of over 2 mines per square meter.
The DMZ is a critical wintering site for migratory red-crowned and white-naped cranes, making it one of the most important crane habitats in the world.
The zone hosts rare plants, including some endemic Korean species like the Geumgang bluebell (*Hanabusaya asiatica*).
An unmanned camera captured the first confirmed photographic evidence of an Asiatic black bear in the DMZ in 2018.