Photo taken on Oct. 28, 2021 shows a man herding on the grassland in Ningxiu Town of Zeku County, Huangnan Tibetan Autonomous Prefecture, northwest China's Qinghai Province. (Xinhua/Zhang Long)

BEIJING, June 18 (Xinhua) -- A study led by Chinese scientists found that anthropogenic activities exert much stronger pressure on vegetation on the Qinghai-Tibetan Plateau than climate change.

Previous studies had indicated that climate variability instead of overgrazing was the primary cause for large-scale vegetation-cover changes on the plateau. However, it remains unclear how human activities such as grazing livestock regulate vegetation dynamics under climate change.

A research group led by Wei Yanqiang from the Northwest Institute of Eco-Environment and Resources under the Chinese Academy of Sciences used the AVHRR/GIMMS Normalized Difference Vegetation Index (NDVI) as an indicator to analyze the spatiotemporal growth status of vegetation on the plateau between 1981 and 2015.

They also examined the dual effects of climate change and human activities by correlation analysis of data from 87 meteorological stations and economic statistical data of the plateau, according to a study published in the journal Earth's Future.

They discovered that vegetation in the high-altitude central and southwestern areas was improving due to the warm-humid climate trends. Global warming led to a temperature increase at high altitudes, resulting in the expansion of vegetation areas.

The findings also revealed that the degraded areas were mainly confined to the northeastern and eastern plateaus with dense human and livestock populations. Compared with the mild changes in climate trends, human activities such as long-term grazing in low-altitude valleys exert more pressure on vegetation in these areas.

The study indicated that the anthropogenic pressures are much more intensive than the impact of climate change and are critical for the conservation and sustainable management of the plateau vegetation.