蒙古高原典型草原景观格局变化及其国别差异

Changes of Landscape Patterns of Typical Grassland in Mongolian Plateau and Their Differences among Countries

摘要: 典型草原作为内蒙古草原带的主要自然景观，是我国北方重要的生态屏障，关乎着我国北方生态安全。本文以蒙古高原典型草原乌珠穆沁–温都尔汗带为例，以1988~2020年6期TM数据为信息源，在获取景观类型信息的基础上，采用景观指数方法，研究了样带景观格局变化及其国别差异。研究发现：① 近30年样带草地和耕地面积呈下降趋势，其他景观类型面积均呈上升趋势。其中耕地减幅最大，为31.48%，集中于蒙古国段；工矿用地增幅最大，为初期的近379倍，集中于内蒙古段。② 景观层次上，近30年样带景观破碎度增加，由集中趋向于分散。在境内外破碎化程度均在增加，但内蒙古段景观格局变化持续向破碎化方向发展，蒙古国段为波动式变化。斑块类型层次上，各景观类型指数变化不一，差异明显。样带蒙古国段和内蒙古段草地斑块景观百分比趋于减小，除了耕地之外的其余斑块类型景观百分比则趋于增大，其中内蒙古段变化趋势较明显。③ 近30年样带景观破碎化程度上升，在内蒙古段尤为严重。除了自然因素，人为干扰对蒙古高原典型草原景观格局变化的贡献占部分比重，尤其是放牧方式和强度。

Abstract: The typical grassland, as the main natural landscape of the Inner Mongolia grassland belt, is an im-portant ecological barrier in northern China, and it is related to the ecological security of northern China. In this paper, the Ujumqin-Undurhan transect, a typical grassland of the Mongolian Plateau, was taken as an example. Based on the 6th TM data from 1988~2020 as the information source, using landscape index method, we analyzed the changes of landscape patterns of the transect and their differences among countries. The study found that: ① In the past 30 years, the area of grass-land and cultivated land in the transect showed a downward trend, while the area of other land-scape types showed an upward trend. Among them, arable land decreased most, at 31.48%, con-centrated in the Mongolian section; industrial and mining land increased largest, nearly 379 times the initial period, concentrated in the Inner Mongolia section. ② At the landscape level, the land-scape fragmentation of the transect has increased in the past 30 years, from concentration to dis-persion. The degree of fragmentation is increasing both at home and abroad, but the landscape pattern change in the Inner Mongolia section continues to develop towards fragmentation, and the Mongolia section is fluctuating. At the patch type level, the index of each landscape type varies, and the difference is obvious. The percentage of grassland patch landscape in the Mongolian section and the Inner Mongolia section of the transect tends to decrease, while the percentage of patch type landscapes in the rest of the patch type except for the cultivated land tends to increase, and the change trend in the Inner Mongolia section is more obvious. ③ In the past 30 years, the degree of landscape fragmentation in the transect has increased, especially in the Inner Mongolia section. Be-sides the natural factors, human disturbance also contributed to the landscape changes of the typi-cal steppe in Mongolian Plateau, especially the grazing method and intensity.