Spatial Distribution Characteristics of Land Use in the Southern Slope of Mid-Himalaya Mountains

摘要

The southern slope of mid-Himalayan Mountains is mainly located in China’s Qomolangma National Natural Reserve in Tibet Autonomous Region,made up of several noncontinuous mountains.The high mountains and deep valleys here make farmlands and grasslands very scarce.Due to its remoteness,only some ethnic groups reside in mountainous areas.Therefore,land resources here are poorly studied with absence of precise land data for years.By now,there is no research report for land use/coverage in this area.Land use/cover change has increasingly been a core issue both in land resource research and management.The problems of land use in Mid.Himalaya mountain area is closely connected with the living level promotion of local habitants as well as the social economy development.This study collected the satellite images of 4 typical valleys located at Mid.Himalaya mountain area on Google Earth Planet Map,from east to west they were: Pengqu Valley,Rongshar Valley,Nyalam Valley & Gyirong Valley.Made use of ArcGIS9.3 spatial analysis technology,analyzed into the 2 aspects—Mountain altitudinal belts and slope gradient of soil types of Qinghai-Tibet Plateau,so as to abtain the spatial distribution characteristics of farmland and grassland in the research areas.The altitude index adopted the 5 ranges(＜2,500m,2,500m-3,800m,3,800m-4,800m,4,800m-5,200m,＞5,200m) of the mountain altitudinal belts; and the slope gradient index adopted the 4 ranges(＜5°,5-15°,15-35°,＞ 35°) of soil types of Qinghai-Tibet Plateau.The results indicate that: (1)no farmland below 2,200m altitude,land use is influenced intensively by slope gradient factor in the altitude range of ＜ 2,500m; (2)it is in 2,500m-3,800m altitude range meanwhile on the 2 farming suitable slope gradient belts(＜5°,5-15°) that the very focus zone has got the relatively larger potential,suitability and yield of farming utilization; (3) it is in 3,800m-4,800m altitude range that the advantaged area of grassland use,in which slope gradient factor influenced relative weakly; (4)on the 3 grazing suitable slope gradient belts(＜5°,5- 15°,15-35°),the respective fodder quantities of the 4 valleys has low differences; (5) The breadthwise comparison of the 4 valleys found that Gyirong Valley holds the most largest available lands in the 4 valleys,then Pengqu Valley,Nyalam Valley and Rongshar Valley.Synchronously,land use of the 4 valleys are intensively restricted by altitude and slope gradient factors so that cultivating and grazing activities take place widely on the farming unsuitable slope gradient belts(15-35°,＞35°) and grazing unsuitable slope gradient belt( ＞ 35°),which is disadvantaged to ecological environmental protection and rational utilization of land resources.The conclusions typically show the situation of land resources utilization and configuration in Mid.Himalaya mountain area,which has great significance to explore the relationship among resource,environment and society development.