蒙古高原草地利用特征及其国别差异

内蒙古草原是蒙古高原草原带的南部组成部分,是我国北方重要的生态屏障,草原生态修复任务重、压力大。本文以蒙古高原典型草原乌珠穆沁—温都尔汗样带为例,以1988—2016年5期TM数据为信息源,获取2016年样带草地利用信息基础上,按国别和年限对样带草地利用特征进行分析,揭示草地主要干扰因素,探寻有效的修复途径和可借鉴的国际经验。研究发现：① 草地面积占样带95.05%,均匀覆盖于整个样带;其他用地类型占比均不大,但分布相对集中,其中耕地集中于样带西北部蒙古国段,工矿用地、沙地、盐碱地集中于样带东南部内蒙古段。② 1988—2016年样带耕地面积减幅最大,为35.71%,集中位于蒙古国段;草地、水域面积逐年减少,在中国境内、境外变化趋势相同,但内蒙古段草地减幅大于蒙古国段且多转为未利用地;工矿用地面积增幅最大,为初期的近367倍,集中分布于内蒙古段;盐碱地、沙地面积逐年增加,在中国境内、境外的变化幅度相当。③ 草地是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。

Characteristics of grassland utilization in Mongolian Plateau and their differences among countries

Located in the southern part of the Mongolian Plateau, the Inner Mongolia grassland is an important ecological barrier in northern China. The ecological restoration is a tough task and poses a great pressure on the grassland. In this paper, we focus on the Ujumqin-Undurhan transect, a typical grassland of the Mongolian Plateau. We used Landsat TM data from 1988 to 2016 which was divided into five periods (of seven years), to reveal the characteristics of grassland utilization in the transect, a transboundary between Mongolia and Inner Mongolia autonomous region of China. In addition, we determined the main disturbance factors of grassland and explored effective restoration mitigation and an international experience for reference. Based on land-use type as of 2016, we found that grassland accounted for 95.05% of the transect, which was evenly distributed across the entire transect. Other land use types accounted for a small proportion, and were relatively concentrated in the localized areas. Among them, cultivated land was concentrated in the Mongolian section in the northwest of the transect, while mining and its industrial area, sandy land, and saline-alkali land were mainly located in the Inner Mongolian section in the southeast of the transect. In the past 30 years, the arable land in the transect decreased the most (35.71%), which was concentrated in the Mongolian section. The area of grassland and water mass suffered a continuous decline with a similar trend both on Chinese and Mongolian sides. However, the decrease in the area of grassland in Inner Mongolia, China was greater than that in Mongolia, and most of them were converted to unused land. The largest increase was found in mining and its industrial area in the transect, nearly 367 times of the initial period, which was concentrated in the Inner Mongolian section. The area of saline-alkali land and sandy land underwent a continuous increase and the changes within the two countries were comparable. Finally, we found the grassland was the predominant land use type on the plateau, which was mainly used for grazing. Mining was the chief disturbance factor of grassland in China, followed by grazing. Meanwhile, the reclamation was the main disturbance factor in Mongolia. The extent of grassland disturbance in Inner Mongolia, China was much greater than that in Mongolia. Overall, grassland degradation and drought were the main ecological and environmental challenges faced by the Mongolian Plateau, especially in Inner Mongolia.