A holistic approach towards assessment of severity of land degradation along the Great Wall in northern Shaanxi Province, China.

The farming and grazing interlocked transitional zone along the Great Wall in northern Shaanxi Province is particularly vulnerable to desertification due to its fragile ecosystem and intensive human activity. Studies reveal that desertification is both a natural and anthropogenic process. Four desertification indicators (vegetative cover, proportion of drifting sand area, desertification rate, and population pressure) were used to assess the severity of desertification in a GIS. The first three factors were derived from multitemporal remote sensing and land inventory data. The last factor was calculated from census data. It was found that the overall severity of land degradation in the study area has worsened during the last two decades with severely, highly and moderately degraded land accounting for 84.2% of the total area in 1998. While the area affected by desertification has increased, the rate of desertification has also accelerated from 0.74 to 0.87%. Risk of land degradation in the study area has increased, on an average, by 155% since 1985. Incorporation of both natural and anthropogenic factors in the analysis provides realistic assessment of risk of desertification.