以滦河流域为研究区域,基于SWAT模型模拟1976-2012年滦河流域的水沙过程,分析2000年京津风沙源治理项目实施前后流域产水产沙时空格局变化;研究1980-2010年流域景观格局变化特征,揭示景观格局变化的水沙响应;应用Spearman相关分析法分析流域景观格局变化对水沙过程的影响.结果表明:与20世纪80年代相比,2010年流域林地和建设用地增加,其他用地类型减小;流域景观集中程度提高、连通性变优、优势斑块显著、形状趋于规则、多样性减少、破碎化程度降低、景观类型向非均衡方向发展;流域年均地表径流减少9mm,产水量增加5.44mm,产沙减小1.59t/hm2;地表径流减少区域占全流域89.32％,产水量增加区域占76.71％,产沙量减少区域占93.89％;地表径流、产水、产沙与林地面积呈负相关,产水与草地面积呈正相关,地表径流、产沙与农业用地面积呈正相关;地表径流、产水、产沙与景观形状、Shannon's均匀度、景观分离度呈正相关,与蔓延度、最大斑块指数呈负相关;产水、产沙与斑块密度和Shannon's多样性指数呈正相关;工程治理后,流域年均径流量与产沙量显著下降,产水产沙高值区显著缩小,产沙关键区域仍需治理.%The Luanhe River Basin is one of the most important sources of sand for sandstorms in Beijing and Tianjin.To alleviate the hazards,a sandification control program for areas near Beijing and Tianjin was carried out in June 2000,which could have changed the landscape pattern of this basin.Firstly,the present study used landscape pattern indices to analyze landscape pattern changes from 1980 to 2010.Secondly,the SWAT model was used to reveal how the changes in landscape pattern influenced the surface runoff,water yield,and sediment yield in 1980 and 2010,and to evaluate the effects of the sandification control program.Additionally,the Spearman Correlation was used to analyze the relationship between landscape pattern changes and flow-sediment process changes.Furthermore,the SWAT model was applied to study the spatial and temporal distribution of the water and sediment yield in the basin before the implementation of the program (1976-1999) and after the implementation of the program (2000-2012),respectively,and identify the critical zones of sediment yield that should be controlled at present in the Luanhe River Basin.The results were as follows:(1) compared with the area of landscape types in 1980s,forest and construction land increased obviously in 2010,whereas the other land use types decreased in 2010.Compared with the landscape pattern in 1980,increases of splitting index (SPLIT),Contagion Index (CONTAG),Landscape Shape Index (LSI),and Largcst Patch Index (LPI),and decreases of Shannon' s Diversity Index (SHDI) and Shannon's Evenness Index (SHEI),diversity of landscape patterns and fragmentation,and more regular landscape shapes and imbalanced development of landscape types in 2010 were also observed.(2) Compared with the flow and sediment processes in 1980,annual average surface runoff was significantly reduced in 2010,with a 9 mm decrease,and the decrease in surface runoff accounted for 89.32％ of the whole basin;the annual average water yield increased strongly in 2010,with a 5.44mm increase,and areas of the increase in water yield accounted for 76.71％ of the basin;average annual sediment yield was obviously reduced,with a decrease of 1.59 t/hm2,and 93.89％ of the basin area showed this trend.(3) Variations in landscape indices were correlated with the processes of flow and sediment well.The surface runoff,water yield,and sediment yield were negatively correlated with the area of forest.The water yield was positively correlated with the area of grassland.The surface runoff and sediment yield were positively dependent on the area of agricultural land.Surface runoff,water yield,and sediment yield were positively correlated with SPLIT,LSI,and SHEI.On the contrary,surface runoff,water yield,and sediment yield were negatively correlated with LPI and CONTAG.Additionally,water and sediment yield both positively correlated with SHDI (Shannon's Diversity Index) and PD (Patch Density).(4) Soil erosion in most zones of Luanhe River Basin has been reduced with the implementation of the program.However,a few zones were still experiencing severe soil erosion that should be taken into account.
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