中文摘要：

河岸缓冲带的植被结构特征是维持其多种生态服务发挥的重要因素。本研究以黄河中下游由丘陵向平原过渡区域的典型河岸缓冲带为研究对象,基于2003、2009和2015年Google Earth高分辨率遥感影像,通过景观格局分析、缓冲分析和回归分析,探讨研究区植被景观格局的时空动态及其驱动因子。结果表明,农田为黄河中下游典型河岸缓冲带景观基质,林地和草地呈逐年增加趋势,受黄河游荡和农业开垦种植与弃耕影响,水体和河漫滩相互转化频繁,农田与其他景观类型转化频率较高,林地的主要转化方向为草地、居民区和农田,草地的主要转化方向为农田和林地,不同时段植被变化的空间分布差异明显。研究区植被景观连通性较高,景观破碎化程度呈逐年增加趋势,景观斑块形状整体趋于复杂化,但不同植被类型存在差异,其中林地斑块的几何形状逐渐复杂,而草地斑块的几何形状逐渐规则,林地的空间连通性高于草地。草地和林地斑块沿居民区、河岸、沟渠、坑塘和道路缓冲具有明显的梯度分布特征,两者在2003—2015年的变化率受河岸和道路缓冲驱动较小,受居民区缓冲驱动显著,而对沟渠和坑塘的响应则存在差异,其中草地变化受沟渠驱动显著,林地变化受坑塘驱动显著。

英文摘要：

Vegetation structure of the riparian buffer zone is of great importance for maintaining various ecological services. Therefore, selecting a typical riparian buffer zone in the transition region from the hills to the plain area of the middle and lower reaches of the Yellow River as the research object, we analyzed the spatialtemporal dynamics of vegetation landscape pattern and the associated drivers, via landscape pattern analysis, buffer analysis, and regression analysis, based on the high resolution remote sensing images in 2003, 2009, and 2015 observed from the Google Earth satellite. The results showed that croplands were the landscape matrix of the typical riparian buffer zone of the middle and lower reaches of Yellow River, and riparian vegetation （forest and grassland） exhibited an increasing trend during 2003-2015. Influenced by the wandering of the Yellow River and agricultural reclamation and abandonment, the mutual transformation between water area and flood pain was frequent, and the transformation frequency from cropland to other landscape types was high. The main transformation directions of forest land were grassland, residential area, and cropland, and the main transformation directions of grassland were cropland and forest land. The spatial distribution of changes in vegetation was different in different periods. Landscape pattern analysis indicated that the landscape connectivity of vegetation in the study area was high, the degree of landscape fragmentation increased gradually, and patch shape tended to be more complicated. However, different vegetation types showed different trends, therein, geometrical shape of forest and grassland patches became more complicated and regular respectively, and spatial connectivity of forest land was higher than that of grassland. Grassland and forest patches showed obvious gradient features along the residential areas, riparian ditches, ponds, and road buffers. Meanwhile, regression analysis indicated that changes in grassland and forest patches were dr