BEIJING, Feb. 6 (Xinhua) -- China's world natural heritage sites, along with its mixed cultural and natural heritage sites, are in sound conservation condition, with no cases of serious human-induced damage or any threats to their outstanding universal value identified, according to a report released by the National Forestry and Grassland Administration on Friday.

The report, which reviews the conservation and development of China's world natural heritage from 1985 to 2025, marks the country's first comprehensive and systematic assessment of its natural heritage assets, the administration said at a press conference.

China now boasts 15 world natural heritage sites and four mixed cultural and natural heritage sites, ranking first in terms of the total number, according to administration official Yuan Jiming.

Ranging from China's southeastern coast to the Qinghai-Tibet Plateau and the northwestern deserts, these sites cover a wide spectrum of ecosystems, including mountains, forests, grasslands, lakes, wetlands, deserts and coastal zones, Yuan said.

China's natural heritage features high value and a full range of types, said Liu Jiaqi, an academician of the Chinese Academy of Sciences.

The Three Parallel Rivers of Yunnan Protected Areas site meets all four natural heritage criteria, while Mount Taishan satisfies the criterion for natural landscapes and all six cultural heritage criteria -- examples that Liu said are rare globally.

The country's 19 natural and mixed heritage sites span about 80,000 square kilometers across 20 provincial-level regions, offering valuable experience for coordinated cross-regional conservation efforts, Liu added.

Last year marked the 40th anniversary of China's accession to the Convention Concerning the Protection of the World Cultural and Natural Heritage. Since joining the convention, China has consistently strengthened the systematic and holistic conservation of its natural heritage, and developed a distinctive approach to conservation and management, contributing the country's experience to global natural heritage protection. ■