The Study On Spatial And Temporal Variation And Characteristics Of Farming-Pastoral Ecotone In Northern China Based On GIS

The interface named Farming-Pastoral Ecotone between planting and stockbreeding which are two important foods product system not only contains a huge production potential, but also to curb desertification, desertification eastward and southward ecological barrier. It also holds the important strategic status in regional economy, the social development and the environmental protection. The Great Wall is enormous cultural borderline created by the climate, vegetation, and human economic activites and historical dividing line between agricultural planting and the pastoral browse. In view of the relationship between Farming-Pastoral Ecotone and the Great Wall, this study focuses on analyzing Spatial and Temporal Variation and Characteristics of Farming-Pastoral Ecotone in northern China Based on GIS .The main contents include: (1) After comparing different definitions of Farming-Pastoral Ecotone , the study chooses ecotone climate indicators system raised by Zhao Halin to define the distribution position of the potential Farming-Pastoral Ecotone in northern China by GIS spatial interpolation analysis and overlay analysis features; the Ecotone system of land-use indicators raised by Wu Chuanjun to define the distribution position of the actual Farming-Pastoral Ecotone in northern China .Then the study analyze the impact of human activities to Ecotone distribution. (2) According to changes of the Great Wall location in different times and the position of actual Farming-Pastoral Ecotone in northern China, the study analyze spatial and temporal variation and characteristics of Farming-Pastoral Ecotone in northern China from the Zhan to present. Combining others study, the paper analyzes the influence of historic climatic and human activities for Farming-Pastoral Ecotone migration in northern China.The conclusion shows as following: (1) The total area of the potential Farming-Pastoral Ecotone in northern China is about 424,100 km2, showing their distribution from northeast to southwest band patterns, and the bandwidth gradually decreases along this direction; The total area of the actual Farming-Pastoral Ecotone in northern China is about 626,000 km , its distribution is more dispersive than potential Farming-Pastoral Ecotone, and its bandwidth is also no obvious changes in regularity. (2) The changes of human production and lifestyle to climate change need "response time". To the distribution of Farming-Pastoral Ecotone, that is the change of actual the location will lag for some time than potential Farming-Pastoral Ecotone. In addition, the northward migration of actual Farming-Pastoral Ecotone has an appropriate "degree" in climate warming period, its size is determined by difference of culture and consciousness among nations, the level of stockbreeding and policies.(3) Since the Zhan to present, the location of Farming-Pastoral Ecotone in northern China changed and took on southward and northward phenomenon. In the Zhan to Qin, Farming-Pastoral Ecotone in northern China emerged northward trend, and the maximum distance is about 150km; from the Qin Dynasty to the Han period, the Farming-Pastoral Ecotone in north China moved to south, and maximum distance is aboutl00km;from the Han Dynasty to the Ming period, the Farming-Pastoral Ecotone in north China moved to south, and maximum distance is about 290km ;from Ming to present, it is also showing a trend of moving northward, and maximum distance is about 300km.(4)The migratory direction of Farming-Pastoral Ecotone depends on Climate change. Humanity social factors decide the migratory distance and speed of Farming-Pastoral Ecotone. The changes of the allocation of resources and environmental caused by climatic change directly trigger conflict between different ethnic groups, the conflict is particularly intense, multi-form solution to the war when these peoples belong to different regimes. (5) In the cold period and warm period, Farming-Pastoral Ecotone magnitude and speed of movement is different, even if the magnitude of climatic change is same. Because the driving force is difference when climatic change toward adverse trend.