YINCHUAN, May 26 (Xinhua) -- Guo Zhihong, a staffer with the Liupan Mountain nature reserve bureau in northwest China's Ningxia Hui Autonomous Region, is lately busy collecting regular photos and videos of leopards roaming in the mountains.

Advanced automatic infrared cameras strategically placed in locations believed to be frequently visited by the elusive leopards capture the photos and videos by skillfully tracking the footprints of these big cats.

"Leopards are the most beautiful animals I have ever seen and every time I get their pictures, I can hardly contain my excitement," said 43-year-old Guo, who has worked in the nature reserve bureau for 24 years.

The leopards in Liupan Mountain are recognized as the North China Leopards, with an estimated population of approximately 30 in the area. As an endangered species, this breed of leopard, also known as the Chinese Leopard, is under first-class national protection in China.

Guo and his colleagues are currently working with a team from the School of Life Sciences, Fudan University in Shanghai, and a scientific education institution in Chongqing Municipality on a research and investigation project for better protection of the big cats.

"We have so far identified 21 individual leopards. Each of them has different streak patterns, which serve as their identity cards," said Wang Fang, a researcher at the School of Life Sciences, Fudan University.

The videos of the leopards showed that male leopards patrolled their territories regularly while marking their presence by applying their distinctive smell on the surrounding objects to establish clear boundaries. With great care, the female leopards held their cubs gently in their mouths as they moved around the area, and some leopard cubs were seen playing in the snow.

"All the video footage shows that the leopards are not migrating, instead, they have chosen to establish a stable breeding population in the area," Wang said.

Situated on the fringes of the North China Leopard's population distribution area, Liupan Mountain holds immense significance as a crucial "shelter" for these magnificent creatures. In the face of climate change and intensive human activities, this mountainous region provides a vital refuge for the leopards. With the restoration of the surrounding ecology, Liupan will become a key channel for the leopard population distribution to expand, according to Wang.

"As the top carnivore, the leopard is an iconic species for an intact and healthy ecosystem, as it requires a large number of herbivores to support its survival," said Song Dazhao, a researcher from Chongqing, adding that the return of leopards, wherever they are, is an important sign of ecology improvement.

With the forest coverage in the mountains exceeding 66 percent, compared with 27 percent in the 1950s, Liupan Mountain stands as a remarkable testament to Ningxia's determined efforts to restore its barren lands through afforestation.