近10年福州市滨海湿地变化研究

Change of Coastal Wetlands in Fuzhou City in Recent 10 Years

利用2000年的Landsat 7 ETM+和2009年的ALOS AVNIR遥感影像数据,对福州市滨海湿地进行分类和专题信息提取。用GIS空间分析功能,对福州市滨海湿地的分布及其变化进行了分析和比较。结果表明,与2000年相比,2009年福州市东海岸的天然滨海湿地面积有所减少,人工湿地面积明显增多;其中,养殖场的面积增加了2699.82hm2,其主要由非湿地、泥滩和水田转化而来;水田面积增加了2484.21hm2,其主要是由非湿地转化而来;建设用地主要占用了养殖场、河流、浅水海域、沙滩和泥滩的用地。大规模的水产养殖、农业建设和城市发展是导致福州市滨海湿地变化的主要原因。

Fuzhou located in the east of Fujian province is one of the areas holding the most abundant wetland resources in Fujian province, which has a large number of coastal wetlands. The coastal wetland ecosystems provides habitat and nursery areas for many commercially important fish and crustaceans. They also play im- portant roles in shoreline protection, chemical buffering, water quality maintenance, recreation and education, and as reservoirs of genetic materials. During the past decades, the distribution and amount of coastal wet- lands have been changed due to human activities, urbanization development, and other economic issues imposed on it, which brought on a series of serious damage to wetland resources. Thus, there is an increasing need to master the distribution and dynamic change of coastal wetlands, which is important to protection, ratio- nal development and utilization of the coastal wetlands in Fuzhou. It will play a promational role on wetland resources investigation, long-term monitoring and scientific management for the province and even the national in the future, and has a strong practical value and broad application prospects. In this study, in order to monitor the change of the distribution and amount of the coastal wetlands in Fuzhou, Landsat 7 ETM＋ image in 2000 and ALOS image in 2009 were used to classify the coastal wetland resources in Fuzhou. In the classifica- tion procedure involved, the images in 2000 and 2009 were classified into 9 land use types, including aquatic farm, mudflat, paddy field, river, shallow water, sandy beach, mudfiat, marshy meadow, reservoir pond and non-wetland, using the conventional unsupervised Maximum Likelihood Classification Algorithm. To im- prove information extraction accuracy from the coastal wetlands, the crude results of unsupervised classifica- tion were refined and optimized. Then the distribution and the spatio-temporal changes of the coastal wetlands were analyzed and compared using GIS analysis function. The results showed that natural wetlands in the east coast of Fuzhou had reduced while artificial wetlands have increased significantly in the past 10 years. Aquatic farm had the largest change with its area increasing about 2 699.82 ha, which were mainly transformed from non-wetland types, mudflats and paddy fields. The transformation of paddy fields were mainly changed from non-wetlands, of which the overall area increased by 2 484.21 ha. As for aquatic farm, river, shallow water, sandy beach and mudfiat, they all had a certain scale of areas that had been converted to construction lands. The changes of coastal wetlands were primarily caused by the increasingly large areas of aquaculture and the development of agriculture and urban construction.