生态系统服务是生态系统产品和服务的统称，是人类直接或间接地从生态系统功能中获得的收益。内蒙古多伦县位于我国北方农牧交错带，属于干旱半干旱气候区，抗干扰能力较弱，不合理的开发利用方式已经造成了一系列的生态、经济和社会问题，例如草原沙化、植被退化等，对多伦县人民的生产与生活产生了威胁。2000年以来，多伦县政府对全县实施了退耕还草工程，效果显著。本文对2000年与2016年多伦县六项基础的生态系统服务进行了评估，并分析退耕还草工程对多伦县生态系统服务的影响，在此基础上从影响因子角度对生态系统服务及其关系进行研究，最后基于生态系统服务间关系机制对生态系统服务间关系尺度效应进行了探究。得出以下结论： （1）多伦县六项生态系统服务从2000年到2016年呈现不同的提升趋势，生态环境有着显著的改观，其中产水量由145.37Mt增加到509.32Mt，土壤保持量由66.71Mt增加到75.92Mt，土壤侵蚀量由2.2Mt降低到0.5Mt，NPP由952.81GgC增加到1719.24GgC，防风固沙量由136.48×〖10〗^3 t下降到63.82×〖10〗^3 t，风力侵蚀量由3.34×〖10〗^3 t降低到0.7×〖10〗^3 t，粮食产量由7.63×〖10〗^5 t增加到9.21×〖10〗^5 t，产草量由1.66×〖10〗^5 t增加到3.85×〖10〗^5 t。六项生态系统服务都呈现不同的提升趋势，生态环境有着显著的改观。 （2）退耕还草工程改变了多伦县土地利用情况以及植被覆盖度，影响了生态系统服务的产生和提供，有效的提高了多伦县的生态系统服务，改善了多伦县的生态环境。由耕地、沙地以及其它土地利用类型转换出现的恢复草地相比于耕地虽然不能提供更高的生态系统服务，但经过一定阶段演替后的草地在未来可以取得更好的生态收益；多项生态系统服务随植被盖度提升而发生改变，植被覆盖度的提升有效增强了NPP与产草服务，且区域保土固土能力与植被覆盖度关系紧密，植被覆盖度的提升一定程度上增强了土壤保持服务与防风固沙服务，但植被覆盖度的提升增强了区域蒸散能力，因此植被覆盖度的提升一定程度上削弱了产水服务。 （3）相比于气候变化，退耕还草工程对多伦县NPP产生了更为重要的影响。其中，多伦县NPP显著的提升主要得益于退耕还草工程中草地管理的相关措施，包括降低放牧强度、调整草地利用模式等等，此外退耕还草措施提升了相对较少的NPP。 （4）植被因子对多伦县生态系统服务有较高的影响，其次是气象因子，地形因子与土地利用因子对一些生态系统服务会产生极为重要的影响，同时土壤因子的影响最小。影响因子对生态系统服务间关系的影响体现在两个层面上，首先是因子的重要性，其次是因子对生态系统服务间关系的影响作用。根据此机制进一步研究，我们发现生态系统服务间关系的粒度与幅度尺度效应是由于尺度变化时影响因子的重要性与影响作用都随之发生变化而导致的。 本研究从影响因子角度细化研究生态系统服务及其关系，并对因子影响生态系统服务间关系的机制进行了探究，有助于管理者更加深入的了解生态系统服务及其关系的现状及影响因子，为在类似区域进行的生态工程提供思路，实现生态、经济和社会的可持续发展提供科学依据。

Ecosystem services (ESs) refer to the benefits directly or indirectly derived by people from ecosystem functions. Duolun County is located in the central part of Inner Mongolia at the southeastern end of Xilingol, Duolun County belongs to the arid and semi-arid climate zone, and is part of typical agricultural-pastoral ecotone in northern China. The anti-interference ability is weak, while the development mode here has caused a series of ecological, economic and social problems, such as grassland desertification, vegetation degradation et cetera, which threatened people in Duolun County. Grain-for-Green Program (GFGP), including one project implemented in Duolun County since 2000, has significantly improved the overall ecological environment of this region. Using a modeling approach, this study quantified six ecosystem services (ESs) in Duolun County between 2000 and 2016, and analyzing the impact of the GFGP on ESs. Based on the results, this study analyzed the ESs and their relationships from the perspective of environmental factors, and explored the scale effect based on the mechanism of the relationships between ecosystem services. The following conclusions are drawn: (1) All six ESs in Duolun County have shown different increasing trends from 2000 to 2016, and the ecological environment has significantly improved. The results show that water yield increased from 145.37Mt to 509.32Mt, soil conservation increased from 66.71Mt to 75,92Mt, soil erosion decreased from 2.2Mt to 0.5Mt, NPP increased from 952,81GgC to 1719.24GgC, soil fixation decreased from 136.48×〖10〗^3 t to 63.82×〖10〗^3 t, soil erosion decreased from 3.34×〖10〗^3 t to 0.7×〖10〗^3 t, NPP increased from 952.81GgC to 1719.24GgC, sand fixation decreased from 136.48×〖10〗^3 t to 63.82×〖10〗^3 t, wind erosion decreased from 3.34×〖10〗^3 t to 0.7×〖10〗^3 t, crop production increased from 7.63×〖10〗^5 t to 9.21×〖10〗^5 t, grass production increased from 1.66×〖10〗^5 t to 3.85×〖10〗^5 t. (2) The GFGP changed the land use and vegetation coverage in Duolun County between 2000 and 2016, and affected the production and provision of ESs. The GFGP has effectively improved the ecosystem services in Duolun County. Compared with farmland, restored grassland can not provide higher ecosystem services, while restored grassland can achieve better ecological benefits in the future after stage of positive succession. At the same time, ecosystem services changed with the increase of vegetation coverage. The improvement of vegetation coverage effectively enhanced these NPP and grass production. The soil-fixing capacity are closely related to vegetation coverage, and the improvement of vegetation coverage enhanced soil conservation services and soil fixation services. While the improvement of vegetation coverage enhanced regional evapotranspiration capacity, so the improvement of vegetation coverage weakened water yield service. (3) The improvement of NPP in Duolun County can be largely attributed to the implementation of the GFGP compared to climate change. We found the change in NPP generated by grassland management measures, including reduced grazing intensity and adjusted grassland utilization pattern et cetera, is far higher than the change in NPP generated by land use circulation. (4) The vegetation factor have a highest impact on ESs, followed by climate factors. Topographic factors and land use factors have a important impact on a few ESs, while soil factors have the smallest impact. It was found that the mechanism of how environmental factors create the relationship between ESs is reflected in two levels: first, the importance of environmental factors, and secondly, the impact of environmental factors. On this basis, the grain and extent scale effects of the relationship between ESs were caused by the changes in the importance and impact of the factors when the scale changes. This study analyzed ESs and their relationships from the perspective of environmental factors, and explored the mechanism of environmental factors affecting the relationship between ESs, which will help managers to better understand the status quo of ESs and their relationships. Providing ideas for ecological management in similar areas and scientific basis for sustainable development of ecology, economy and society.