黄渭洛三河汇流区湿地景观变化

流域经济快速发展使得黄河、渭河及北洛河三河汇流区湿地景观变化显著。应用GIS/RS技术与景观格局分析软件FRAGSTATS,对1989、1996、2000年5月黄渭洛三河汇流区湿地景观的演变过程进行计算和分析,探讨了湿地景观格局特征的变化趋势以及湿地景观演化的驱动力因素,主要结论为:①水文因素和人文因素是汇流区景观变化的主要驱动力;②草地、盐碱地和裸地的面积在增加,而耕地和水域的面积在减少;③土地盐碱化形势依旧严峻,分别有1.38 km2的耕地、0.54 km2的草地和0.47 km2的水域演化为盐碱地;④景观指标表明湿地景观多样性和均匀性逐年升高。

Landscape changes of wetland in confluent area of the Yellow River,Weihe River and Beiluohe River

Landscape of wetland in the confluent area of the Yellow River,Weihe River and Beiluohe River fluctuates obviously because of rapid development of region economy.The historic data sets are derived from 1989,1996 and 2000 Landsat TM images after supervised classification and visual interpretation,geometrically correction with the relief map of 1982.Based on the technology of GIS/RS and using FRAGSTATS,the processes of wetland changes in confluent area between the year of 1989,1996 and 2000 are analyzed,the characteristics of wetland quantity change and wetland landscape pattern's dynamics and driving forces are also discussed.The results show that:(1)the area of meadow,saline-alkaline land,naked land,woodland are increasing,while the areas of tilth land and water body are declined with 1.38 km2 tilth and 0.54 km2 meadow have been salinized and alkalinized,and 0.47 km2 water area have converted into pickled land with the decrease of river runoff;(2) the connectivity of dominated patches is declining gradually and its fragmentation and heterogeneity are increasing currently;(3)the contradictions among industrialization,urbanization and food security and between agricultural development and eco-environmental protection are the main driver for landscape change in flooded areas,and the runoff changing and population increasing are also the important driving forces.The only way for land management in flooded areas is to exploit the resources above the ecological dead line and reconstruct the vegetation belt along the river banks.