中文摘要：

通过不同年代地形图、卫星影像的对比及野外实地测量等，综合分析了黄河三角洲北部开敞型和潮沟型两类贝壳堤岛近50年来的数量和面积变化及其演化特征。结果表明，该区两类贝壳堤岛自20世纪50年代以来在自然和人为因素的共同作用下发生了明显的变化，但其演化特征因岛屿成因的类型差异而各不相同。目前，该区贝壳堤岛群逐渐萎缩，人类活动已成为影响三角洲北部两类贝壳堤岛发育演变的主导因素，特别是潮沟型贝壳堤岛，基本上结束了自然演化的历史，呈现出新的演化特征。

英文摘要：

This study presents an analysis of the evolution of shell ridge islands on the front margin of the abandoned delta lobe and of the storm shell islands on the head of the tidal river gulf or on the outer side of the tidal channel in northern Yellow River delta. Using comparisons of topographic maps, Landsat images and other survey results during different times as well as new survey data, the changes of quantity, area and evolution characteristics about the two kinds of shell ridge islands have been studied. Since 1950s, the shell ridge islands in the northern Yellow River delta have changed a lot because of natural and human activities, while they have different evolution results from different formation courses. Human activities have been considered as the main restrictive factor in the recent evolution development of the shell ridge islands. At present, the shell ridge islands are changing dynamically, especially the natural evolvement course of the storm shell islands on the head of the tidal river gulf or on the outer side of the tidal channel is almost ended and turning into a new estate.