Livestock and wildlife graze on rangelands, grasslands, savannas and marshes that cover 45 percent of Earth's land surface. Damage or degradation on these lands is a major concern globally, and the subject of widespread scientific study in countries including Mongolia.
An estimated 70 percent of the rangelands in Mongolia are damaged by livestock and unregulated land use. But new research led by Colorado State University found less irreversible damage -- up to 10 percent at most -- from livestock in Mongolia's rangelands. This positive news is countered by findings that show key areas in the country may be reaching a tipping point of irreversible damage.
The study, "Applying a dryland degradation framework for rangelands: the case of Mongolia," is published in Ecological Applications.
Lead author Chantsaa Jamsranjav, a postdoctoral researcher in the Department of Forest and Rangeland Stewardship at CSU, said the research team hopes the findings will generate greater understanding about the deterioration of what Mongolia's citizens call the "green gold" or vast grasslands that cover three quarters of the country.
Scientists said that they are also hopeful that the study will help guide management of these extensive natural resources.
"We wanted to build a clear definition of degradation that can be commonly used in Mongolia," said Jamsranjav. "Having a unified understanding can lead to more targeted national policies for rangeland management, as well as providing help for herders on how to better manage resources by rotating herds and resting pastures."
The Mongolian herding tradition dates back at least 4,000 years -- well before the time of Genghis Khan -- and breeding and caring for sheep, cattle and other livestock contributes up to 15 percent of the country's total gross domestic product. Irreversible land degradation is a growing concern, as these areas must continue to support livestock that outnumber Mongolians 20-1, a ratio consistently among the highest in the world.
Defining degradation
To study grazing impacts, the research team sampled data in 36 counties (soums, as they're called) across 10 provinces, or aimags. Scientists analyzed climate and ground measurements, and chose winter shelters and pastures as a focal point for the project. Families that raise livestock live in these shelters only during the winter, which allows the pastures to rest from livestock use during the summer growing season.
The team collected extensive ecological field data for the study to better measure degradation or damage. Based on these measurements, they classified each sampled area into a different stage, or step, of degradation. The first step, 0, is considered "undergrazed" in rangelands that, like Mongolia, have evolved with many native grazers. Step 0 also incorporates natural climatic fluctuations as part of these natural rangeland ecological processes. Step 4, on the other end of the scale, indicates potentially irreversible changes in vegetation and soil surface due to excessive grazing or other human-driven disturbances, including development of roads and industrial land use.
The research team also compared this new set of measurements with data from two other national studies, and found the same conclusion: very severe or irreversible damage is rare in Mongolia, with most rangelands only slightly or moderately degraded.
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