Study On Terrain Gradient Effect Of Land Use Change In The Border Area Between China And Vietnam(guangxi Section)

Land use / cover change has been an important part of global environmental variation research,which affects the structure and function of the regional ecological environment system.Knowing terrain gradient of land use /land cover change is important to explore sustainable ecosystem management and maintain regional ecological security.The eight counties and cities in the border of Guangxi province are windows of China to Vietnam and ASEAN,most of which belong to the typical Karst Area and have extremely fragile ecological environment.In recent years,with the increasing frequent bilateral trade between China and Vietnam and the continuous improvement of industrialization and urbanization level,the land use intensity of the border area between china and Vietnam(Guangxi section)has increased.The ecological environment problems caused by the increasing of land use intensity should not be underestimated.At present,it has aroused extensive social concern.In order to reveal terrain gradient of the land use change in the border area between china and Vietnam(Guangxi section),this paper takes twenty-six counties(cities and districts)in the border area between China and Vietnamese(Guangxi section)as the research object,which includes eight counties and cities of Guangxi and eighteen of Vietnam border.The research uses the 3S technology and remote sensing image data of 2005,the 2010 and 2015 and DEM data as the data source,adopts the terrain index model,the dominant distribution index model,analysis terrain gradient of land use in the border area between China and Vietnam and Propose countermeasures and suggestions.The main conclusions are as follows:(1)The land use changes of the border areas in Guangxi and the border area of Vietnam adjacent to Guangxi are significant during the study,especially in the areas of urban villages and industrial and mining land.The woodland is the main land use type in the border areas in Guangxi and the border area of Vietnam adjacent to Guangxi.In three periods,the woodland area of Guangxi border area accounts for more than 55% of the total land area,while the woodland area of the border area of Vietnam adjacent to Guangxi accounts for more than 74%.The woodlands in the two research areas are gradually decreasing.The situation is serious that the farmland and woodland are occupied by construction in Guangxi border area.During the research time,the farmland and woodland are substantially decreased,while the urban villages and the land of industrial and mining are substantially increased.In the border area ofVietnam adjacent to Guangxi,the land reclamation is so common that it causes reduction of large woodland area and the increasing of farmland.(2)Terrain factors have a significant influence on the distributions,changes of land use types and dominant distribution.On the whole,farmland,urban villages and industrial and mining land,water and water conservancy facilities and transportation land have dominant distribution at low altitude,low slope and low land shape.However,woodland,grassland and other land have dominant distribution at high altitude,high slop and highland shape.The terrain factors also have a significant effect on the dynamic degree of land use and the comprehensive index of land use degree.Firstly,the dynamic degree of land use in two research areas are extremely slow changeable types in general.The dynamic degree of land use varies significantly on different relief amplitudes.Second,the comprehensive index of land use degree in the two research areas decreases along with the rise of terrain roughness during three periods.