The ecosystems of Southwest China's Xizang Autonomous Region — home to the world's highest and largest plateau — have remained stable in the past two decades, according to a study by Chinese scientists.

From 2000 to 2020, the rate of change in ecological patterns in Xizang was less than 1 percent, which is lower than the rate for the rest of the nation, according to the study led by researchers from the Chinese Academy of Sciences' Institute of Mountain Hazards and Environment based in Chengdu, Sichuan province.

Meanwhile, the region's role in sequestrating carbon, conserving water, retaining soil as well as wind prevention and sand fixation during the period had either maintained steady or slightly increased, and the population of local wild animals and plants showed signs of growth.

"Our research shows that Xizang continues to be one of the regions with the best ecology and environment in the world, and provides a solid foundation for China's construction of an ecological security barrier in the region," said Wang Xiaodan, a researcher at the institute.

Xizang, sitting on the Qinghai-Tibet Plateau commonly known as "the roof of the world", has played a unique and paramount role in promoting biodiversity and preserving ecological security in China and neighboring countries, said researchers.

Melting snow and ice from the plateau region feed major rivers across Asia and provide crucial water resources for people living downstream. The region is also home to a number of special ecological zones that provide habitats for alpine animals and plants.

"Another moniker for the region is that it is a climate regulator of the world. For China and even the entirety of Southeast Asia, the region is essential in ecological security," said Wang.

But at the same time, Xizang is highly vulnerable to global warming, said Wang, adding that monitoring its ecological changes is crucial to informing the formulation of policies to conserve and protect its fragile ecosystem.

"Conservation efforts will be complicated and difficult in the long run," he said.

Studies carried out by researchers at the institute show that from 2000 to 2020, the forest coverage rate in Xizang increased to 12.31 percent, and the forest area rose to 2.28 billion cubic meters. The forest area is defined as the total volume of the stems of all living trees per unit area and is used as a predictor of carbon-related variables and carbon stocks.

The region's grassland vegetation coverage reached 47 percent, and its grassland's productivity and quality had also risen.

Moreover, 66 percent of natural wetlands were being effectively preserved. The desert area decreased by 35,000 hectares, and hazardous sand and dust weather events in areas prone to experiencing them had significantly dropped.

Xizang is now home to various types of nature reserves covering a total area of 412,300 square kilometers, taking up over one-third of the region's area.

Effective measures have also been implemented to conserve 217 species of wild animals and 38 species of wild plants under State protection.

Regarding air quality, the studies showed that the annual average concentrations of two types of particulate matter known as PM10 and PM2.5 in major cities and townships across Xizang had fallen by 28.1 percent and 37.5 percent respectively from 2015 to 2020. There had also been a marked decrease in sand and dust storms in the region.

Improving ecology has won recognition from local herders and farmers. Through participation in ecological preservation projects or claiming subsidies from local governments, they have managed to improve their livelihoods, according to the studies.