川西高原荒漠化时空变化特征及驱动力分析

发布时间：2018-11-05 18:16

【摘要】：土地荒漠化作为最严重的生态问题之一,给生态环境、资源等带来巨大的危害,制约着社会经济发展和人民群众生活水平的提高,甚至危及到居民的生存,是阻碍一个地区可持续发展的重要因素。准确地对荒漠化进行评价,及时、有效掌握荒漠化变化动态及驱动因素,对指导荒漠化防治决策有重要的意义。川西高原位于四川西部,是四川荒漠化最严重的地区之一,本文根据荒漠化定义,在前人对荒漠化评价指标选取原则的基础上,结合川西高原荒漠化实际情况,对川西高原荒漠化进行了评价,并分析了川西高原2001-2014年荒漠时空变化特征和驱动力,主要成果和结论如下:(1)从植被、地形、土壤、气候四个方面选取了植被覆盖度、坡度、土壤质地、湿润指数构建了荒漠化评价指标体系,并对川西高原荒漠化进行了评价,得到该地区2001-2014年荒漠化空间分布。大部分荒漠化地区分布于沙鲁里山以西及其附近和巴颜克拉山北部以及大雪山、邛崃山、岷山等地区。(2)2001-2014年荒漠化逆转面积约8745.81km~2,占研究区面积的3.51%,荒漠化发展为4666.50km~2,占研究区面积的1.87%。其中,重度荒漠化面积年均变化率最大,轻度和中度变化率较小,但轻度和中度荒漠化土地在14年内的变化面积、转移速率均较大,而重度荒漠化面积的变化面积、转移速率较小,轻度、中度和重度荒漠化均呈减少趋势,说明这14年自然环境的在逐渐改善,且轻度荒漠化土地和中度荒漠化土地对该时期环境变化的响应最大。(3)不同高程下,荒漠化分布不同。海拔高的地区由于山顶积雪和冰川堆积,以及积雪和冰川融化对该地区的侵蚀作用,使该区域内植被覆盖极少,存在着大量荒漠化,海拔较低的地区植被生长环境较好,受到侵蚀作用较小,荒漠化较少。(4)川西高原荒漠化主要驱动力有自然和人为两种,自然驱动因素对荒漠化变化的贡献率较低,人为驱动因素贡献率较大。不同海拔下,自然和人文因素对其贡献率不同,海拔越高的地区荒漠化变化受人为因素影响越小,自然因素影响越大。在人口素质的不断提高和国家政策的鼓励下,川西高原环境在人为作用下不断得到改善,荒漠化逐渐减少。
[Abstract]:As one of the most serious ecological problems, land desertification brings great harm to the ecological environment and resources, restricts the social and economic development and the improvement of the people's living standard, and even endangers the survival of the residents. It is an important factor that hinders the sustainable development of a region. It is of great significance to evaluate desertification accurately and to grasp the dynamic and driving factors of desertification change in time and effectively. The western Sichuan Plateau is located in the western part of Sichuan Province, and is one of the most serious desertification areas in Sichuan. According to the definition of desertification, this paper combines the actual situation of desertification in the western Sichuan Plateau on the basis of the principle of selecting desertification evaluation index by predecessors. The desertification in western Sichuan Plateau is evaluated, and the characteristics and driving forces of desert temporal and spatial variation in West Sichuan Plateau from 2001 to 2014 are analyzed. The main results and conclusions are as follows: (1) vegetation coverage is selected from four aspects: vegetation, topography, soil and climate. The evaluation index system of desertification was constructed by slope, soil texture and moisture index, and the spatial distribution of desertification in West Sichuan Plateau was obtained from 2001 to 2014. Most of the desertification areas are located in the west of and near the Shaluli Mountains and the northern part of the Bayankra Mountains, as well as in the regions of Daxue Mountain, Qionglai Mountain and Minshan Mountains. (2) the area of desertification reversal in 2001-2014 is about 8745.81 km2, accounting for 3.51% of the study area. Desertification develops to 4666.50 km2, accounting for 1.87% of the study area. Among them, the average annual change rate of severe desertification area is the largest, while the change rate of light and moderate desertification area is small, but the change area and transfer rate of light and moderate desertification land in 14 years are larger, but the change area of heavy desertification area is larger. The rate of transfer is low, and the trend of slight, moderate and severe desertification is decreasing, which indicates that the natural environment is gradually improving in the past 14 years. The response of light desertification land and moderate desertification land to the environmental change in this period is the largest. (3) the desertification distribution is different under different heights. High altitude areas, due to the accumulation of snow and glaciers at the top of the mountain and the erosion of the region by the melting of snow and glaciers, result in very little vegetation cover in the region, large amounts of desertification, and a better vegetation growth environment in areas with lower elevations, (4) the main driving forces of desertification in western Sichuan Plateau are natural and man-made, the contribution rate of natural driving factors to desertification change is low, and the contribution rate of human driving factors is larger. At different elevations, the contribution rate of natural and human factors is different. The higher the altitude is, the smaller the influence of human factors is, and the greater the influence of natural factors is. With the continuous improvement of population quality and the encouragement of national policy, the environment of western Sichuan plateau is improved continuously under the artificial action, and desertification is gradually reduced.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X171

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