Using NASA satellite data, researchers have discovered that plant life in the region around Mount Everest, and across the Himalayas, is expanding.
Using satellite data, researchers have measured the extent of the plants growing between the tree line and the snow line, also know as the subnival vegetation.
There is limited knowledge about these remote ecosystems, comprising of short plants, predominately grasses and shrubs, and seasonal snow. This study revealed that these short plants cover between 5 and 15 times the area of permanent glaciers and snow.
While assessing data gathered by NASA’s Landsat satellites from 1993 to 2018, a team of researchers from the University of Exeter (UoE) measured significant increases in subnival vegetation cover across four height brackets from 4,150 to 6,000 metres above sea level.
The results of this study varied at different locations and heights. The strongest trend in increased vegetation cover, discovered by UoE scientist, was found to be in the 5,000m to 5,500m bracket.
In the area around Mount Everest, the team of researchers found a significant increase in vegetation in all four brackets. The conditions at the top of the height range have been considered to be close to the limit of where plants can grow.
“A lot of research has been done on ice melting in the Himalayan region, including a study that showed how the rate of ice loss doubled between 2000 and 2016,” said Dr Karen Anderson, of the Environment and Sustainability Institute on Exeter’s Penryn Campus in Cornwall.
“It’s important to monitor and understand ice loss in major mountain systems, but subnival ecosystems cover a much larger area than permanent snow and ice and we know very little about them and how they moderate water supply.
“Snow falls and melts here seasonally, and we don’t know what impact changing subnival vegetation will have on this aspect of the water cycle – which is vital because this region (known as ‘Asia’s water towers’) feeds the ten largest rivers in Asia.”
Dr Anderson said “some really detailed fieldwork” and further validation of these findings is now required to understand how plants in this high-altitude zone interact with soil and snow.
Dominic Fawcett, who coded the image processing, said: “These large-scale studies using decades of satellite data are computationally intensive because the file sizes are huge. We can now do this relatively easily on the cloud by using Google Earth Engine, a new and powerful tool freely available to anyone, anywhere.”