Lake Hovsgol, Mongolia

Flickr/tiarescott

Changes in the climate and land use are colliding around Lake Hovsgol in northern Mongolia, threatening to tip the delicate ecosystem into irreversible decline.

Straddling the southern edge of the Northern Hemisphere's permafrost, the lake provides drinking water for the country, and livestock graze its steppes.

Ecologists from the United States and the National University of Mongolia are using a five-year, US$2.5 million grant to study Hovsgol's environmental degradation.

Since the fall of communism in 1991, Mongolians have returned to the land in great numbers, with the steppes supporting 35 million head of livestock herded by inexperienced herders who do not know how to prevent overgrazing.

Overgrazing and increasing temperatures — up 3.6 degrees Celsius in winter over the last 60 years — have combined to disturb the soil structure around the shallow tree roots of the forests surrounding the lake.

Flash floods caused by erratic rainfall are becoming increasingly common, while drought and dzud — a layer of frozen rain over vegetation — have devastated agriculture.

The research team will map the receding permafrost, streams and distribution of plants, and measure the effects of temperature, vegetation cover and other soil factors to find out if this degradation is irreversible.

Link to full article in Science