黑河流域典型区土地利用格局变化及影响比较

Comparison of Spatial Diversity of Land Use Changes and the Inpacts on Two Typical Areas of Heihe River Basin

在黑河流域选择两个典型区域进行土地利用变化的空间差异与影响的对比研究,利用20世纪60年代以来的三期遥感数据,通过定量表征指标体系,对比分析了两个区域不同空间土地利用格局变化和土地利用类型变化的分异特征,定量评价了土地利用变化对不同区域绿洲系统的稳定性和水资源空间分配的影响。结果表明:过去35年来两个对比区域不同的土地利用格局变化,形成了显著的绿洲沿河流的溯源迁移和以基于下游老绿洲的渐进性绿洲外围拓展两种不同模式,前者导致流域水资源过度集中消耗于流域上游和源区,中下游水资源可利用量急剧减少,在35年间下游荒漠化土地增加了85.1%,灌溉绿洲萎缩了25.5%;后者则不同,水资源利用量的空间配置在区域下游具有小幅度集中,区域绿洲系统整体的稳定性较高。从流域整体的水土相互关系出发,合理规划干旱内陆流域土地利用模式和空间土地资源配置,对于促进流域整体的可持续发展具有重要意义。

Land use changes have a great impact on water resources and environment of arid inland regions. In the Heihe river basin, two typical areas were chosen to compare their spatial diversities of land use change and their impacts. Based on three periods of remote sensing data since the 1960s and the quantitative index system, the characteristics of land use pattern changes and land use type changes were compared and analyzed between the two areas, and the impact of land use changes on the stability of oasis system and spatial distribution of water resources in different areas were quantitatively assessed. The results indicate that different land use pattern changes have led to the formation of two different modes in the last 35 years. One is obvious shifting of oasis to headwater and upstream regions; the other is progressive prolongation around downstream old oasis periphery. The former leads to excessive centralized consumption of water resources in the upstream and headwater regions, and rapid decrease of the available water resources in the mid- and down-streams. Within the 35 years, the desertified land at downstream increased by 85.1% and irrigated oases shrank by 25.5%; however, the latter is different. The spatial distribution of water resource utilization centralized in the downstream regions with a small range, and the stability of the whole oasis system was quite high. In view of the relationship between water and land of the whole river basin, reasonable planning of land use mode and land resource distribution in an arid inland river basin is very meaningful to the improvement of the sustainable development of the whole river basin.