A bear population reduced to just 5 individuals in the 1990s has been rebuilt through releases. Genetic studies show extreme bottleneck effects, making it a case study in conservation genetics.
A Population Reborn
The Asiatic black bear (Ursus thibetanus), a creature important to Korea's founding mythology, once roamed the peninsula's mountainous terrain. However, a combination of habitat destruction during the Korean War, poaching for medicinal uses, and eradication programs led to its near-total disappearance from South Korea by the late 20th century. By the early 2000s, it was estimated that fewer than five individual bears survived in the wild, isolated within Jirisan National Park. This dire situation prompted the South Korean government to launch an ambitious restoration project in 2004.
The project, managed by the Korea National Park Service's Species Restoration Technology Institute, began by releasing an initial six bears sourced from Russia's Primorsky Krai. Over the following years, a total of 27 cubs from both Russia and North Korea were imported and released into Jirisan. The effort was a direct intervention to pull the species back from local extinction. The population has responded positively; by early 2024, the number of bears in and around Jirisan had grown to 86 individuals, exceeding the initial target of establishing a self-sustaining population of 50.
The Genetic Echo of a Bottleneck
The success in population numbers is part of the story. The near-extinction event created an extreme genetic bottleneck, a scenario where the gene pool of a population is drastically reduced. The entire rebuilt population is descended from a very small number of founders, creating long-term challenges for genetic health.
To understand these challenges, scientists have analyzed the bears' genetic makeup using mitochondrial DNA (mtDNA) and microsatellite markers. Studies confirmed that the bears from Russia and North Korea belong to the same subspecies, Ursus thibetanus ussuricus, and form a single evolutionary unit distinct from bear populations in Japan or Southeast Asia. This finding validated the choice of source populations for the reintroduction.
Analysis of 16 microsatellite loci showed that the genetic diversity of the reintroduced bears was reasonably high, with an expected heterozygosity of 0.648 for the Russian bears and 0.676 for the North Korean bears. Sourcing bears from two different locations was a beneficial strategy for maximizing the genetic diversity of the new founder group. Despite this, the population's future health depends on careful management to avoid inbreeding and preserve the limited genetic variation that remains.
💡Fun Facts
The Asiatic black bear is also called the "moon bear" because of the distinct V-shaped or crescent-shaped white patch of fur on its chest.
Despite being carnivorans, their diet is primarily vegetarian, consisting of acorns, berries, and other plant matter. They have a powerful sense of smell, able to locate grubs a meter underground.
Asiatic black bears are skilled climbers and spend almost half their lives in trees, where they feed, rest, and even build nests to sleep in.
While some northern populations hibernate, many Asiatic black bears do not. Instead, they may simply move to lower elevations during the winter. Pregnant females, however, almost always hibernate to give birth in a den.
The park is open year-round, but specific trails may close during spring (early March to mid-May) and fall (mid-November to mid-December) for fire prevention and ecosystem protection.
Admission
Free admission to the park itself, though fees may apply for parking, camping facilities, and cultural heritage sites within the park.
Accessibility
The park consists of mountainous terrain with varied trails, from easy walks to strenuous multi-day treks. Trails are natural and can be rocky or steep.