Staff members check a surveillance camera at the entrance of Yele Nature Reserve in Sichuan. [Photo provided to China Daily]

He says staff will first ask any visitors about their purpose. The core area of the nature reserve is not open to tourists, and those who come for scientific research or other work must have a permit.

Rangers can capture images of suspicious activity in the system and put offenders on a blacklist, so the face-recognition function will give a warning when they come again.

If someone covers an automobile plate so it's unreadable, the system will warn the rangers. When they input a car's plate number, they will get all images of the automobile so they can trace its route.

Hu says it takes seven or eight days for more than 20 rangers to patrol the entire reserve once a month. Patrols may be boring, but the rangers are happy to be maintaining the beauty of the green mountains and waters.