Vegetation is expanding across the Himalayas

Today’s Image of the Day from NASA Earth Observatory features vegetation throughout the Himalaya Mountains, where grasses and shrubs have been thriving in recent decades. 

Karen Anderson, an eco-hydrologist at the University of Exeter, was exploring rock glaciers in the Himalayas in 2017 when she began to wonder how plant coverage has changed across the region. 

According to NASA, research in other parts of the world has shown that changes in the type and expanse of vegetation can lead to changes in the flows and stores of water. Ultimately,  the extent of vegetation in the Himalayas has an influence on the water supply for about one-fifth of the global population.

“There is such a lack of information about Himalayan ecology in this high-altitude zone, at least in western science, that we don’t really understand what the impacts of changing vegetation will be,” said Anderson. “Most of the scientific expeditions to the Himalaya have been to the glaciers, which have been an area of major concern as they retreat under climate change.”

The researchers focused their study on how plant life has changed in the Hindu Kush Himalaya over a span of 26 years from 1993 to 2018.

To map the abundance of vegetation across the subnival zone, the team used the Normalized Difference Vegetation Index, or NDVI, derived from Landsat satellites.

The experts found small but significant increases in vegetation during the study period. The biggest gains were located on steeper slopes at lower elevations, and on flatter areas at higher elevations. 

“This work was the first step towards trying to explore the scale of this ecosystem, to describe how it is changing, and to discuss the likely implications,” said Anderson.

“As glaciers recede and plants expand with climate change, what will this mean for water security? I think this is a really important question and something that my research group is taking forward.”

The study is published in the journal Global Change Biology.

Image Credit: NASA Earth Observatory/ Joshua Stevens 

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By Chrissy Sexton, Earth.com Editor

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