黄河中游河龙区间是我国退耕还林／还草工程（Grain for Green Project,GGP）实施的重点区和典型区．定量评估该流域植被动态及其对径流的影响，对流域水资源可持续利用以及GGP工程的生态水文效应评价具有重要意义。该研究基于遥感、GIS技术、数理统计和布迪克弹性系数法，利用7期植被类型数据，定量评估了37年来河龙区间植被覆盖的时空变化格局及其对径流变化的影响。 结果表明：（1)植被变化并未显著地改变河龙区间各植被类型的时空分布格局；（2)GGP的实施改变了各植被类型的平衡状态和转化速度； (3）植被变化是GGP实施后10年 (2000一2010年）径流下降的主要驱动因素，但随后降水的持续增加，使得植被的“减水效应”趋于缓和。

The Hekouzhen-Longmen region of the middle reaches in the Yellow River is a key and typical area for the implementation of the Grain for Green Project (GGP) in China. It is of great significance for the sustainable utilization of water resources and the eco-hydrological effect assessment of the GGP project to quantitatively evaluate the vegetation dynamics and its impact on runoff in the basin. Based on remote sensing, GIS technology, mathematical statistics, and Budyko framework, the spatial-temporal change pattern of vegetation cover and its impact on runoff change is quantitatively evaluated using different vegetation type data of seven periods in the Hekouzhen-Longmen region for past 37 years. The results indicate that; 1) the change in vegetation do not significantly change the temporal and spatial distribution pattern of each vegetation type in the Hekouzhen-Longmen region;2) the implementation of the GGP change the equilibrium status and transformation rate of each vegetation type;3) vegetation changes are the main driving factor of runoff decline after the implementation of GGP in the last 10 years ( 2000-20l0), but the subsequent continuous increase in precipitation make the ”water reduction effect” of vegetation tend to ease.

国家自然科学基金项目（41877158;41701019〕