Landscape change and human activity analysis on desertification process in northern China

Background/Question/Methods

Desertification is one of the most serious environmental and economic problems in the world nowadays. About two-thirds of the countries, one-fifth of the global population and one-fourth of the earth land are now affected by desertification. There are a large scale of areas widely covered by deserts and heavy losses from desertification in Northern China. Understanding the causes of desertification was the key to combat land desertification. However, there were considerable debates on the causes of desertification in Northern China. In this study, the driving factors (natural and human activities) of land desertification had been analyzed with a case of Yanchi County in Ningxia Hui Autonomous Region to understand the reasons of land desertification. Yanchi County is classical in the agro-pastoral mixed regions with farmland, grassland and sand dunes, where desertification is severe.  Over years, the landscape changes from grassland and farmland to desert (such as sand dunes).Using the Landsat TM imagines of June in 1986, 1995, 2000 and 2005, we will examine the dynamics process of landscape patterns.  Based on the economic and meteorological data, the contribution rates of the driving factors and their temporal change in the process of land desertification are investigated using factor analysis in Yanchi County.

Results/Conclusions

The results showed an increase in farmland and a decrease in grassland. The contribution rates of human activity factor are 60.66%, 72.22% and 57.82% respectively in the three periods of 1953-1980, 1981-2002 and 1981-2006, showing that human activity is the leading factor to the land desertification development. The human activity intensity in the period of 1981-2002 is stronger than that in the periods of 1953-1980. The result indicated that the effects of farmers’ operating activities increased after the application of the household contract responsibility system. The human activity contribution to the land desertification decreased after application of prohibiting graze policy in 2002, suggesting that prohibiting graze policy played an important role in controlling land desertification.