Analysis of Roles of Human Activities in Land Desertification in Arid Area of Northwest China

The important conflict in arid area is the negative effect of human activities to environment for which the land desertification is taken in the leading position. Based on the characteristics of arid area and the concept of land desertification given by ”United Nations Convention to Combat Desertification in Those Countries Experiencing Serious Drought and /or Desertification, Particularly in Africa, 1994, 10 in Paris”, the conceptual model of desertification causes is built. In this model, the natural factors include geology, climate, hydrology, vegetation and land and the human operates on these natural factors. The different natural factors have different ways of human activities. Through the analysis on specialties and meaning of human activities, the human activities are thought as consisting of driving and manner factors. Further, the manners and driving force of human activities on land desertification are studied. According to some criterions, an indexes system which shows the human activity effect on desertification in arid area is designed. The most of indexes are quantitative in this system and it can indicate the dynamic changes. Thus, the indexes system can supply the basis for the quantifying study of human effect on desertification.