内蒙古荒漠草原防风固沙服务变化及其驱动力

荒漠化是内蒙古荒漠草原面临的最严重的生态环境问题之一，而风蚀则是造成土地退化的主要因素。采用修正风蚀方程（Revised wind erosion equation，RWEQ）定量评估了内蒙古荒漠草原2000和2017年的固沙量，并结合土地利用、降水、风速、植被覆盖度数据分析了该区域防风固沙服务的影响因素。结果表明：内蒙古荒漠草原的防风固沙服务表现出明显的空间异质性，不同土地利用类型提供的防风固沙服务有所差异，其中高覆盖度草地的固沙量相对较高。总体来说，2000年固沙量与降水、风速、植被覆盖度均为正相关，2017年固沙量与降水为负相关，与风速和植被覆盖度为正相关。2000-2017年内蒙古荒漠草原固沙物质总量增幅为53.95%，其中9.65%来源于土地利用变化区域，土地利用方式发生变化的面积占研究区总面积的5.6%。2000-2017年土地利用变化以林地的恢复、建设用地的扩张以及不同覆盖度间草地的转换为主。2000-2017年，风力因子的分布模式对防风固沙服务的空间分布变化的影响较大。总的来说，土地利用变化对内蒙古荒漠草原的防风固沙服务有一定的增强作用，防风固沙服务的空间分布在时间上的变化主要受气候因子的影响。

Changes of windbreak and sand fixation services and the driving factors in the desert steppe, Inner Mongolia

Desertification is one of the most serious ecological and environmental problems in the desert steppe, Inner Mongolia, and wind erosion is the main factor causing land degradation. In this paper, the Revised Wind Erosion Equation (RWEQ) was used to quantitatively evaluate the amount of sand fixation in desert steppe of Inner Mongolia in 2000 and 2017. The influencing factors of windbreak and sand fixation service in this area were analyzed based on land use, precipitation, wind speed and vegetation data. The results showed that the windbreak and sand fixation services of desert grasslands in Inner Mongolia presented obviously spatial heterogeneity, and the windbreak and sand fixation services provided by diverse land use types were different. Among them, the amount of sand fixation in high-coverage grasslands was relatively high. In general, in 2000, the amount of sand fixation was positively correlated with precipitation, wind speed, and vegetation coverage, while in 2017, the sand fixing amount was negatively correlated with precipitation and positively correlated with wind speed and vegetation coverage. The results showed that the total amount of sand fixation increased by 53.95% from 2000 to 2017, of which 9.65% originated from land use changed areas, and the area of land use change accounted for 5.6% of the total area of the study area. The land use change type in 2000-2017 was mainly consist of the restoration of forest land, the expansion of construction land and the conversion of grassland between different cove degrees. From 2000 to 2017, the distribution pattern of wind factors had a greater impact on the spatial distribution of windbreak and sand fixation services. In summary, land use change has a certain enhancement effect on the windbreak and sand fixation services of desert grasslands in Inner Mongolia, and the changes of the spatial distribution of the services are mainly affected by climate factors.