Understanding land structure change and stability in the process of oasisization is particularly important for the desertification control in sandy land. Based on land use data of eight periods from 1980 to 2020, we extracted the spatial distribution information of oasis land in Mu Us Sandy Land, and analyzed the spatio-temporal variations of land transformation patterns and stability of oasis land with overlay analysis and grid analysis. The results showed that desertification in the Mu Us Sandy Land had reversed, with a significant process of oasis. The area of forest and grassland increased from 10.2% in 1980 to 73.7% in 2020, while the area of oasisization land increased from 32500 km2 in 1980 to 33900 km2 in 2020. The area of extremely severe, severe, and moderate desertification significantly decreased, while the area of non-desertification and mild desertification obviously increased. The four patterns of oasisization land transformation, including stability, fluctuation, expansion, and retreat, which accounted for 78.7%, 12.2%, 6.2%, and 2.9% of the oasisization land area in 2020, respectively. The oasisization land with low change intensity (the cumulative change intensity less than 0.12) in the Mu Us Sandy Land accounted for 82.7% of the total oasisization area, and the oasisization land in the sandy land was generally stable. Zoning management strategies should be applied according to the stability of sand belt and transformation pattern of oasisization land to achieve the goal of efficient system management and improvement, including eliminating sand hazards at desertification expansion areas with strong wind and sand activities, consolidating sand resources at oasisization areas where ecologically fragile desertification was frequent, and sustainably managing and utilizing sand resources at stable expansion of oases in forest- and grass-rich oasisization areas.
绿洲化过程中的土地结构变化和稳定性研究对沙地荒漠化治理尤为重要。本研究基于1980—2020年8期土地利用数据,提取了该时间段毛乌素沙地绿洲化土地空间分布信息,使用叠置分析、格网化等方法,分析毛乌素沙地绿洲化土地变化模式和稳定性的时空分异特征。结果表明: 研究期间,毛乌素沙地荒漠化问题已得到有效解决,并成功实现逆转,绿洲化过程显著,林草覆盖率从1980年的10.2%增长到2020年的73.7%,绿洲化土地面积从1980年的3.25万km2增长到2020年的3.39万km2,极重度、重度和中度荒漠化面积大幅下降,非荒漠化和轻度荒漠化面积大幅上升;绿洲化土地变化表现为稳定、波动、扩张和退缩4种模式,2020年这4种模式的绿洲化土地面积占比分别为78.7%、12.2%、6.2%和2.9%;毛乌素沙地累积变化强度较低的绿洲化(低于0.12)占总绿洲化土地面积的82.7%,沙地绿洲化总体趋于稳定。针对毛乌素沙地稳定沙带及不同变化模式绿洲化土地应采用适宜的分区治理对策,其中,在风沙活动强烈的沙漠化扩张区域歼灭沙害;在生态脆弱、沙漠化反复的绿洲化区域巩固风沙治理成效;在林草资源丰富的稳定扩张绿洲化区域,应积极开展对沙地资源的持续管理和利用,以实现沙地系统治理和提质增效的目标。.
Keywords: Mu Us Sandy Land; change mode; governance measure; oasisization land; stability.