The altitude challenge

Despite advances, the reserve's gibbon population has remained frustratingly stable — around 50 individuals across 19 groups, including 14 families and 5 solitary adults.

Meanwhile, populations in nearby Yingjiang county have grown to more than 100.

The difference lies in elevation, Li Jiahong explained. Gibbons naturally prefer altitudes around 1,500 meters, where the climate is warmer and food is abundant. But centuries of human activity — clearing forests for farming, planting sugarcane and coffee — have pushed Gaoligong's gibbons steadily upward. Today, they survive at elevations of 2,000 meters or higher in cold, marginal habitats.

"In Yingjiang, the elevation is around 1,600 to 1,700 meters, which is much more suitable," Li said. "That's why their population has expanded faster."

The solution, he believes, is helping gibbons return to lower elevations by restoring degraded forests on collectively owned land below the reserve — creating corridors and planting food trees like long-stamen magnolia that provide year-round sustenance.

Sometimes the barriers are smaller than a mountain. A road, a landslide clearing, a gap in the canopy — any of these can stop a gibbon that rarely descends to ground. In collaboration with researchers at Sun Yat-sen University, the reserve has begun installing simple rope bridges at key locations to connect fragmented forest sections.

The protection strategy extends beyond the reserve's core zone. In 1996, recognizing that the gibbons' habitat was becoming fragmented, authorities established a 4,800-hectare biological corridor connecting the Gaoligongshan National Nature Reserve with the Xiaoheishan Provincial Nature Reserve. "Before this, the state-owned forest in between was not well protected, and wildlife couldn't move between the two reserves,"Ding explained, standing at the edge of the now-lush corridor. Today, this green bridge teems with life — infrared cameras frequently capture red panda, Chinese goral, and the increasingly numerous red spurfowl, proof that protecting the flagship gibbon shelters an entire ecosystem.