基于国别的蒙古高原土地沙漠化对比研究

Land desertification is one of the major ecological and environmental problems humanity facing in the 21st century. The Mongolian Plateau is located in the inland of Asia. It is a widely distributed area of sandy land and desert with a typical temperate continental climate zone. It is also one of the areas where land desertification occurs seriously and affects one of the core issues of ecological security, social stability and economic development in the northern border of China. The same natural background, the same environmental problems and human interference in different countries are superimposed together, becoming an ideal "sample" for studying the humanized driving factors of desertification. This study intends to select the same area in the temperate typical steppe zone of the Mongolian Sukhbatr province of Maurer and the Xilin Gol grassland Ujumqin sandy land, Inner Mongolia. This paper aims to research desertification land between countries by using 2-5 remote sensing data of MODIS,TM and high-resolution satellites, and combining with detailed population, livestock statistics and meteorological and dust disaster data, using GIS modern technology and field research, interview investigation, statistical analysis and other research methods. First of all, it is necessary to fully understand the characteristics of the two sandy beaches and their differences, and on this basis, improve the interpretation index system of desertified land. Secondly, through the interpretation and superposition analysis of multi-source and multi-period remote sensing images, the scale, development trajectory and rate of desertified land in different countries are compared. Thirdly, analyze and sort the interference degree of natural and human influence factors to clarify the humanistic contribution of land desertification in arid and semi-arid grassland. Finally, the rational approaches and scientific methods for remediation of desertified land in the Mongolian Plateau, ecological restoration of sandy land and sustainable use of grassland in the sandy area will be provided to decision-making services for the construction of ecological barriers in the north of China and the construction of the Sino-Mongolian economic corridor. The research results not only fill the gap in the comparative study of land desertification among countries, but also become an effective discussion on the international cooperation mechanism of desertification land remediation and ecological restoration, which has high theoretical significance and practical value.

土地沙漠化是21世纪人类所面临的重大生态环境问题之一。蒙古高原位于亚洲内陆，属于典型的温带大陆性气候区，是沙地、沙漠广泛分布的区域，也是土地沙漠化发生发展严重的地区之一，是影响我国北部边疆生态安全、社会安定与经济发展的核心问题之一。同一自然背景、同样环境问题与不同国家人类干扰叠加在一起，成为研究土地沙漠化人文驱动因子的理想“样本”。本研究拟选取同处于温带典型草原带的蒙古国苏赫巴特尔省毛勒朝格沙地和中国内蒙古锡林郭勒草原乌珠穆沁沙地，利用MODIS、TM以及高分卫星等不同分辨率的2-5期遥感数据，并结合详实的人口、家畜统计数据和气象、沙尘灾害等器测数据，借助GIS现代技术手段和实地踏查、访谈调查、统计分析等研究方法，开展国家间沙漠化土地的对比研究。首先，要充分理解两个沙地自然环境特征及其相互之间差异，并在此基础上完善沙漠化土地的判读指标体系；其次，通过多源、多期遥感影像的解译和叠加分析，对比不同国家沙漠化土地的发生规模、发展轨迹和速率；再次，分析并排序自然、人文诸多影响因子的干扰程度，来阐明干旱半干旱草原地区土地沙漠化的人文“贡献”；最后，凝练蒙古高原沙漠化土地整治、沙地生态恢复与沙区草地可持续利用的合理途径与科学方法，为我国北方生态屏障建设和中蒙俄经济走廊的搭建提供决策服务。研究成果不仅填补国家间土地沙漠化对比研究的空白，更会成为沙漠化土地整治与生态修复国际合作机制的有效探讨，具有较高的理论意义和实践价值。

在未来的较长时期，土地沙漠化仍然是人类共同面临的重大环境问题之一。中国是土地沙漠化发生发展最严重的国家之一，而内蒙古是土地沙漠化重灾区。呼伦贝尔沙地集中分布于内蒙古呼伦贝尔市西部，生态区位十分重要。蒙古国哈拉哈沙地位于该国东部东方省南端，紧邻国境线，与呼伦贝尔沙地的直线距离不足100km，也属于大陆性气候区。目前两个沙地均属于当地牧民的放牧草场，土地利用类型一致。项目选取该两个沙地为研究区，利用TM影像、高分影像数据，以及统计数据、器测数据，借助遥感、GIS技术和实地踏查、统计分析等方法，对蒙古高原境内外沙漠化土地的发生规模、发展轨迹和速率以及影响因子进行对比分析。研究结果表明：. ① 草地是目前蒙古高原主要土地利用类型，放牧是草地主要利用方式，开矿是除放牧以外中国草地的主要干扰因子，蒙古国则为垦殖，内蒙古的草地干扰远大于蒙古国；草地退化与干旱化是蒙古高原面临的主要生态环境问题，在中国境内尤为突出。. ② 近40年蒙古高原典型草原气候整体出现暖干化趋势，而沙尘天气却在减少，尤其自2000年以来中国北方沙尘天气显著减少，而蒙古国和塔克拉玛干沙漠等区域均在增长。. ③ 目前境内沙地以固定、半固定沙丘为主，近30年研究区自然生态环境持续好转，景观稳定性在增加；但在境外，哈拉哈河流域裸沙面积呈递增趋势，导致沙地的持续扩张。. ④ 随着放牧强度的增加，植物群落结构逐步向退化方向演替，土壤颗粒随放牧频率的增加逐渐细化，适度放牧有利于提高群落物种多样性与生物量。.. 研究按计划进行，完成了计划的大部研究内容，部分达到了预期的研究目标。