共和盆地土地利用/覆盖变化（LUCC）及其驱动因素

The study of land use/cover change (LUCC) and its driving forces in Gonghe Basin, northeastern Qinghai-Xizang Plateau

关键词:  LUCC  人类活动  共和盆地  黄河源  青藏高原

Key words:  LUCC  human activities  Gonghe Basin  source region of the Yellow River  Qinghai-Xizang Plateau

摘要:

青藏高原是我国重要的生态安全屏障，在人类活动不断增强的影响下，青藏高原局部地区的生态安全正面临新的挑战。共和盆地位于青藏高原东北部，是青藏高原典型的农牧交错区之一。近几十年来，该地区农业开垦面积和工业建设用地面积急剧增加。为详细掌握该地区的土地利用/覆盖变化（LUCC）特征，以Landsat系列遥感影像为数据源，通过地理信息系统（GIS）技术对该地区1977、2000和2018年的土地利用/覆盖进行监测。监测结果显示：草地和未利用土地是共和盆地最主要的土地利用/覆盖类型，分别占研究区面积的64.9%和22.7%。1977—2018年水库坑塘、旱地和其他建设用地的面积增加最明显，分别增加341.0、229.4和47.5 km²。与此同时，中、低覆盖度草地和沙地的减少面积最大，分别减少229.3、197.5和120.7 km²。通过土地利用/覆盖的转移路径和驱动因素分析发现：人为因素是共和盆地LUCC的主要驱动因素，自然因素的影响非常有限。对于青藏高原人类活动密集地区，如何实现环境保护与经济建设的协调发展是当前亟需解决的问题。

Abstract:

Background, aim, and scope Qinghai-Xizang Plateau is the “Water Tower of Asia” and the “Third Pole of the Earth” and an important ecological security barrier of China. However, under the influence of increasing human activities, the ecological security in some areas of Qinghai-Xizang Plateau is facing new challenges. Gonghe Basin is located in the northeastern Qinghai-Xizang Plateau, and one of the typical agro-pastoral zones in China. Therefore, the basin is an ideal region for the study of man-earth relationship in Qinghai-Xizang Plateau. According to our field investigation, it is found that the area reclaimed for agriculture and used for industrial construction increased sharply in the past decades. Revealing the influencing factors of land use/cover change (LUCC) can provide scientific basis for efficient comprehensive and decision-making management for the local government. Materials and methods Remote sensing monitoring was applied to reveal the details of LUCC in this region. Landsat remote-sensing images recorded in 1977, 2000 and 2018 were applied to assess land use/cover change (LUCC) in Gonghe Basin, based on geographical information system (GIS) software and field investigations. The land use/cover transition matrix during 1977—2000 and 2000—2018 was obtained by overlay analysis. Results The remote sensing monitoring result shows that grassland and unused land are the most important land use/cover types in Gonghe Basin, accounting for 64.9% and 22.7% of the study area, respectively. From 1977 to 2018, the area of reservoir and pond, dry land and other construction land increased by 341.0, 229.4 and 47.5 km², respectively. Meanwhile, the area of medium and low coverage grassland and sandy land decreased the most, decreased by 229.3, 197.5 and 120.7 km², respectively. Discussion The spatial distribution of annual mean precipitation in Gonghe Basin shows that the spatial distribution pattern of land use/cover is mainly influenced by precipitation. However, the bare rock and gravel land in surrounding high elevations is influenced by vertical variation of air temperature. In the past decades, the increase of population and infrastructure construction have caused great impact on LUCC not only in Gonghe Basin but also in the whole Qinghai-Xizang Plateau. These changes include land reclamation, construction of hydropower station and photovoltaic power station. The ecological risks and ecological environmental effects of major construction projects in the Qinghai-Xizang Plateau need to be paid attention, and how to realize the coordinated development of environmental protection and economic construction is an urgent problem to be solved in the areas with intensive human activities in the Qinghai-Xizang Plateau. Conclusions Based on the analysis of land use/cover transfer paths and driving factors, it is concluded that human factors are the main driving factors of LUCC in the Gonghe Basin, while natural factors have limited influence. Recommendations and perspectives This regional study of LUCC provides details of land transfer paths, which is helpful for understanding the environmental changes triggered by human activities in the Qinghai-Xizang Plateau.