七里海湿地土地利用变化及其景观格局演替分析

通过遥感手段，利用大量的ETM、TM、MSS遥感影像，从土地覆盖变化、景观格局指数等角度，分析了近30年七里海湿地的土地利用变化特点及景观演替趋势特征。详细分析了七里海内水域、芦苇等用地类型的转化趋势与成因，并通过多年来景观指数对比的方法揭示了该区域景观连通性和破碎化程度的变化趋势。研究结果表明：由于入境水量减少，1976到2009年期间七里海湿地水域面积减少了80％，之后由于保护区的建立，水域面积持续增长。期间以保护区建立为节点，主要的土地利用类型变化趋势是水域-芦苇-水域。1976到2009年期问七里海总体聚集度指数从95．75下降到87．54、水面的破碎化指数从6．42上升到10．74，反映出区域景观连通性变差，破碎化程度在加剧，人类活动对环境影响越来越深刻。

Land Use Pattern Change and Landscape Evolution Process for Qilihai Wetland in Tianjin

The trend characters of the land-use change and landscape succession in Qilihai Wetland within nearly 30 years were analysed from the land use change, landscape pattern index by means of remote sensing, a large number of ETM, TM and the MSS remote sensing images. The detailed analysis of the trends and causes of the conversion of waters, reeds and other land use types revealed the trends of the regional landscape connectivity and the degree of fragmentation by the method of landscape index contrast. The results showed that as the entry water reduced, the water area in Qilihai Wetland reduced by 80 percent during the years 1976-2009, and then the water area continued growth after the establishment of protected area. The major land use change trended waters-reeds-waters by establishing the protected areas. The overall aggregation index decreased from 95.75 to 87.54 and the surface fragmentation index increased from 6.42 to 10.74 during 1976-2009 in Qiliha wetland. That showed the regional landscape connectivity was becoming worse, the degree of fragmentation was more severe, and the human activity was influencing the environment more and more obviously.