若尔盖高原土地沙化及其成因定量分析

Dynamic changes of land desertification in Zoige Plateau

若尔盖高原是世界上最大的高原泥炭湿地之一。受自然条件、人类活动等影响,该区域出现了湿地草地退化、土地沙化的现象。为全面掌握该区域土地沙化状况,文中基于Landsat TM影像分析了1995-2016年若尔盖高原沙地时空变化,并借助地理探测器方法定量分析土地沙化的成因。结果表明:近二十年间,该区域沙地呈增长趋势。2006年以前沙地增长较快,主要分布在若尔盖县西北部和玛曲县东南部,降水和放牧强度是该时期土地沙化关键驱动因子;2006-2016年间,降水量增加、放牧强度减弱,沙地增长速度有所下降;1995-2016年间,任意两驱动因子交互作用大多表现为非线性增强,即各因子共同作用增强了沙化程度。

The Zoige Plateau is one of the largest plateau peat wetlands in the world.Affected by natural conditions,human activities and so on,the wetland degradation,grassland degradation and land desertification occurred in the region.In order to fully understand the situation of land desertification in this area,we analyzed the spatial and temporal changes of sandy land in the Zoige Plateau from 1995 to 2016 based on Landsat TM image,and quantitatively analyzed the causes of land desertification by means of geo-detector method.The results show that in the past two decades,the sandy area in the region has shown an increasing trend.Before 2006,the sandy land increased rapidly,mainly in the northwest of Zoige County and southeast of Maqu County.Precipitation and grazing intensity were the key driving factors for land desertification in this period.During 2006-2016,precipitation increased,grazing intensity weakened,which made the growth rate of sandy land declined.during 1995 and 2016,the interaction of any two driving factors mostly showed nonlinear enhancement,that is,the interaction of various factors enhanced the degree of desertification.