URUMQI, April 1 -- National nature reserves in the Altun Mountains, Hol Xil and Changtang in northwest China have banned illegal entry in order to protect the fragile environment, they said in a joint notice on Tuesday.

Altun Mountains in Xinjiang Uygur Autonomous Region, Hol Xil in Qinghai Province and Changtang in Tibet Autonomous Region, cover an area of about 340,000 square kilometers and are home to the endangered Tibetan antelope, wild yak and Tibetan wild donkey.

A number of outdoor enthusiasts organized illegal activities online and entered core areas of the nature reserves in recent years, which damaged the plateau ecology and the habitat of the wild animals, according to the notice.

The three nature reserves will share intelligence of illegal entry and jointly crack down on the activity. Those who seriously damage the natural resources and environment will be turned into the police, it said.