中文摘要：

以1955~2004年遥感影像为数据源,结合野外调查,运用景观生态学原理,研究50 a间北海市滨海湿地的景观格局及其动态变化。结果表明,50 a间北海市滨海湿地呈整体退化趋势,潮间砂质海滩、潮间淤泥质海滩、红树林滩、小型岛屿湿地减少;景观格局指数显示1977年、1998年是北海市滨海湿地较明显变化的拐点。1977年人类活动影响增加,滨海湿地稍有退化,湿地景观多样性指数减小,优势度指数增加,均匀度指数减小、景观总面积指数降至最低值。1988年湿地保护力度加大,湿地略为好转,景观多样性指数、优势度指数、均匀度指数则呈相反规律。1998年湿地受到的极端气候灾害、人类干扰程度加大,平均斑块分形维数下降,斑块密度指数、景观斑块数破碎化指数呈最高值。湿地景观格局指数的变化,反映了围垦改造、互花米草的生物入侵、城市污染、极端气候灾害等对景观格局的影响,人类活动是北海市滨海湿地景观格局变化的主要驱动因子。

英文摘要：

With landscape ecology theory as a basis, we studied the landscape pattern of Beihai＇s costal wetland and its dynamic changes over the past 50 years （1955--2004） using remote sensing images as the data source in addition to a field survey. The results show that over the past 50 years, Beihai＇s coastal wetland has experienced a degrada- tion trend, with decreases in the inter-tidal sandy beaches, inter-tidal silt beach, mangrove beach, and small-sized island wetland. The landscape pattern indexes indicate that 1977 and 1998 witnessed obvious changes to Beihai＇s coastal wetland. In 1977, the impact of human activities increased, which caused a slight degradation in the coastal wetland, as indicated by the increased dominance index of the wetland landscape, decreases in the diversity and evenness indices, and a reduction in the total landscape area index to its minimum. In 1988, wetland protection ef- forts were enhanced, and the wetland recovered somewhat. For instance, the landscape diversity index, dominance index, and evenness index showed opposite patterns. Due to the increased levels of extreme weather and human disturbance to the wetlands in 1998, its mean patch fractal dimension decreased, while the patch density and land- scape fragmentation indices reached their maxima. Changes in the wetland landscape pattern index reflected the influence of the following factors on the landscape pattern： reclamation transformation, biological invasion of spartina alterniflora, urban pollution, and extreme weather disasters. Of these factors, human activities were the major driving force behind the changes in the landscape pattern of the coastal wetland in Beihai.