【作者】 吴佳；

【导师】 荣丽；

【作者基本信息】 云南大学 ， 自然地理学， 2024， 硕士

【摘要】 土壤侵蚀是存在于世界的一种自然现象,是地貌自然演化过程,长期的土壤侵蚀会导致土地退化和贫瘠、土地生产力降低、水污染等问题。随着地表生态过程逐渐受人类行为主导,除降雨、地形和植被覆盖等自然因素,人类活动也成为影响土壤侵蚀的一个重要因素。高黎贡山作为我国西南生态安全的第一道屏障,在国家生态安全战略中具有特殊地位。高黎贡山南北地形差异大,陡坡土地利用较多、人地关系复杂使得土壤侵蚀空间异质性增强。区域内的人类活动造成的土壤侵蚀问题会威胁高黎贡山的生物多样性和生态安全。但目前针对整个高黎贡山的研究集中在生物多样性、土壤类型和植被等,缺少土壤侵蚀的时空分异规律总结和影响因素分析,不利于区域土壤侵蚀防治和可持续发展政策的制定。本研究基于中国水土流失方程(CSLE)模型,定量评估研究区2000、2010和2020年土壤侵蚀并分析其时空分异,收集自然和社会经济数据,通过偏最小二乘回归定量分析自然和社会经济因素对该区域的土壤侵蚀影响,划分重点治理区域。主要研究结果如下:(1)高黎贡山主要侵蚀强度为微度侵蚀,分布在中部的腾冲市,剧烈侵蚀主要分布在北部的贡山县。各侵蚀强度面积为:微度侵蚀>轻度侵蚀>中度侵蚀>强烈侵蚀>极强烈侵蚀>剧烈侵蚀。2000-2020年高黎贡山土壤侵蚀得到缓解,土壤侵蚀面积从4352.6 km2减小到3710.92 km2,土壤侵蚀量从2344.05万吨减少到1985.93万吨,平均土壤侵蚀模数从10.08 t·hm-2·a-1下降到8.54 t·hm-2·a-1。(2)在耕地、林地、草地和灌木四种土地利用类型中,林地以微度侵蚀(<5 t·hm-2·a-1)为主,面积为17503.18 km2,侵蚀面积为513.22 km2;灌木的侵蚀面积最多,为1796km2,侵蚀模数主要为50-80 t·hm-2·a-1;草地的平均侵蚀模数最大,为48.11 t·hm-2·a-1,土壤侵蚀量最大,为6.75万吨;耕地的侵蚀面积最小,为342.13 km2,主要分布在南部平坦地区。剧烈侵蚀分布在耕地、草地、林地、灌木和裸地。其中,草地分布的剧烈侵蚀的面积最多,为135.5km2,耕地次之,林地最小。2000-2020年,耕地和草地的剧烈侵蚀面积呈减少趋势,林地、灌木和裸地的剧烈侵蚀面积呈增多趋势。(3)剧烈侵蚀主要分布在>25°的区域,平均海拔为3065 m,土地利用为草地。>25°的区域贡献了研究区58.33%的土壤侵蚀量,>35°区域平均土壤侵蚀模数最大,为12.36t·hm-2·a-1,25-35°和>35°区域中度侵蚀及以上的面积均减少,其中>35°地区的中度侵蚀面积减小幅度最大,为114 km2。(4)偏最小二乘回归模型表明高黎贡山土壤侵蚀的主要自然因素是年降雨量和地形,主要社会经济因素是土地利用和人口。2000-2020年,社会经济因素对土壤侵蚀量的贡献率逐渐增大,从50.41%增加到60.99%,说明社会经济因素对土壤侵蚀的影响也越来越大。根据以上对高黎贡山土壤侵蚀程度时空分异和驱动因子分析结果,初步划分高黎贡山土壤侵蚀重点防治区和重点治理区,建议重点治理区25°以上的区域要加强草地保护与合理利用,对破坏严重的草地,进行种植恢复工作,合理控制放牧。更多还原

【Abstract】 Soil erosion is a natural phenomenon that exists in the world,and it is a natural evolution process of landforms,and long-term soil erosion will lead to land degradation and barrenness,reduced land productivity,water pollution and other problems.As the surface ecological process is gradually dominated by human behavior,in addition to natural factors such as rainfall,topography and vegetation cover,human activities have also become an important factor affecting soil erosion.As the first barrier of ecological security in southwest China,Gaoligong Mountain has a special position in the national ecological security strategy.The spatial heterogeneity of soil erosion is enhanced due to the large difference in topography between the north and south of the Gaoligong Mountain,the steep slope has more land use and the complex human-land relationship.Soil erosion caused by human activities in the region threatens the biodiversity and ecological security of the Gaoligong Mountain.However,the current research on the entire Gaoligong Mountain focuses on biodiversity,soil types and vegetation,and lacks the summary of the spatiotemporal differentiation of soil erosion and the analysis of influencing factors,which is not conducive to the formulation of regional soil erosion prevention and sustainable development policies.Based on the Chinese Soil Erosion Equation(CSLE)model,this study quantitatively evaluated the soil erosion in the study area in 2000,2010 and 2020,analyzed its temporal and spatial differences,collected natural and socio-economic data,and quantitatively analyzed the effects of natural and socio-economic factors on soil erosion in the region through partial least squares regression,and divided the key treatment areas.The main findings are as follows:(1)The main erosion intensity of Gaoligong Mountain is slight erosion,which is distributed in Tengchong City in the central part of the country,and severe erosion is mainly distributed in Gongshan County in the north.The areas of each erosion intensity are as follows:slight erosion>light erosion>moderate erosion>strong erosion>very strong erosion>intense erosion.From 2000 to 2020,soil erosion in Gaoligong Mountain was alleviated,the soil erosion area decreased from 4352.6 km2 to 3710.92 km2,the soil erosion amount decreased from 23.4405 million tons to 19.8593 million tons,and the average soil erosion modulus decreased from 10.08 t·hm-2·a-1 to 8.54 t-hm2·a-1.(2)Among the four land use types of cultivated land,woodland,grassland and shrub,the forest land was mainly slightly eroded(<5 t·hm-2·a-1),with an area of 17503.18 km2 and an erosion area of 513.22 km2.The shrub erosion area was the largest,which was 1796 km2,and the erosion modulus was mainly 50-80 t·hm-2·a-1.The average erosion modulus of grassland was the highest(48.11 t·hm-2·a-1),the highest soil erosion was 67,500 tons,and the erosion area of cultivated land was the smallest(342.13 km2),which was mainly distributed in the southern flat area.Intense erosion is distributed in cultivated land,grasslands,woodlands,shrubs,and bare land.Among them,the area of grassland distribution with severe erosion was the largest,which was 135.5 km2,followed by cultivated land and forest land.(3)Severe erosion is mainly distributed in the area of>25°,with an average altitude of 3065 m,and the land use is grassland.The area of>25° contributed 58.33%of the soil erosion in the study area,and the average soil erosion modulus was the largest in the>35° area,which was 12.36 t·hm-2·a-1,and the area of moderate erosion and above in the 25-35° and>35° areas decreased,among which the area of moderate erosion decreased the most in the>35° area,which was 114 km2.(4)The partial least squares regression model showed that the main natural factors of soil erosion in Gaoligong Mountain were annual rainfall and topography,and the main socio-economic factors were land use and population.From 2000 to 2020,the contribution rate of socio-economic factors to soil erosion increased gradually,from 50.41%to 60.99%,indicating that the influence of socio-economic factors on soil erosion was also increasing.According to the above analysis results of spatiotemporal differentiation and driving factors of soil erosion degree in Gaoligong Mountain,the key prevention and control areas of soil erosion in Gaoligong Mountain were preliminarily divided,and it was suggested that the area above 25° of the key treatment area should strengthen the protection and rational use of grassland,carry out planting and restoration work for the seriously damaged grassland,and reasonably control grazing.更多还原