More than 3,000 Tibetan antelopes stopped under the shadow of the Wudaoliang North Bridge on the Qinghai-Tibet Railway. After a few hesitant minutes, the antelopes passed through the shadow to continue their migratory journey.

The scene was observed in real time by Li Hongqi on his computer through a high-definition monitoring system as he sat in his office in Xining, Qinghai province, on the morning of Aug 8.

"We know the Tibetan antelopes will come in July and leave in August on certain dates, but this was the largest single group we saw through the monitoring system," said Li, head of the Qinghai Environmental Information Center.

A year earlier, he had shown President Xi Jinping the same system, with live views of the source of the Yellow River, the Wudaoliang bridge and other locations that the environmental information center monitors.

Xi visited Qinghai province on Aug 23 and 24 of last year and talked with grassroots cadres and environmental protection officials at two ecological monitoring sites via video from the information center.

Xi emphasized the importance of protecting the environment of the source region of three great rivers — the Yangtze, Yellow and Lancang — and asked the environmental protection controllers to fulfill their duties to safeguard the lakes, grasslands, rivers, wild animals and other ecological resources of the province.

Tashi Tsering, one of the controllers, lives in the village of Changjiangyuan and drives more than 1,000 kilometers on each of the trips he makes to patrol his jurisdiction near the Tuotuo River. He carries tents and food for the trip, which usually takes three days.

It rained heavily on the day he started his patrol in August, and the rain made the roads difficult to use in the rural area. Tsering had to rent a motorbike.

"I became an environmental protection controller in 2013. The grass this year has grown the finest and the weather has been great," said Tsering, a former shepherd.

In 2004, more than 400 shepherds including Tsering moved down from the area around the sources of the three rivers at an altitude of about 4,700 meters above sea level to the southern suburb of Golmud and formed the new village of Changjiangyuan.

Gega Namgyee, deputy secretary of the village, explained his reason for the move.

"We need to support the protection of the three-river source because it's our home. We need to protect the environment like our own lives.

"I believe in the Chinese Communist Party, so I followed its lead."

In 2016, Xi visited Changjiangyuan and asked the villagers about their life after they moved down from the mountains. Learning that the villagers had stable incomes, basic health insurance and old-age insurance, Xi was delighted and said, "A better life for you lies ahead."

While their previous annual income was less than 2,000 yuan ($300), each villager now earns more than 20,000 yuan, Gega Namgyee said.

"The day President Xi visited our village was the most unforgettable and happiest day of my life," he said.

"It's been a year since his visit and our village is getting better with all the electric wires moving underground."

Tsering is paid 1,800 yuan a month as an environmental protection controller, plus can do part-time work between patrols.

Married this year, the 38-year-old is expecting his first child in October.

Tsering was among the first group of environmental protection controllers in Chang-jiangyuan. But all villagers are aware of the need to protect the environment. They clean the village together on certain days every month.

Tsering's niece Paima Ga, 15, moved to the village when she was 3. She takes part in the cleaning duties. Her father is an environmental protection controller like her uncle. When her father is away for a few days, she knows he has gone to check the grasslands.

Each summer vacation, Paima Ga returns to the Tuotuo River area to watch traditional horse races.

"The grass now is better than before," she said.

Studying at Golmud Ethnic middle school, Paima Ga has adapted to a semiurban life.

"I like living here. I can make many friends, eat many vegetables and go shopping."

Paima Ga wants to study filmmaking.

"I want to be a director in the future," she said. "I can film the legends of the Tibetan ethic group and record the beautiful natural scenery of my hometown."