黑河和白河流域湿地变化及其归因分析

Analysis on wetland change and its attribution in Heihe River and Baihe River basins

通过构建决策树模型对黑河、白河流域沼泽化草甸湿地、沼泽湿地、湖泊等主要湿地类型进行划分,选取3种景观格局指标分析湿地类型的变化特征,采用主成分分析方法对湿地变化的驱动因素进行分析。结果表明:2000年以来,黑河、白河流域湿地总面积呈增加趋势,沼泽湿地变化趋势与草甸湿地相反,存在此消彼长的特征;两河流域湿地变化的地域分异显著,黑河流域草甸湿地面积呈扩大态势,破碎化程度降低,沼泽湿地有所减少,但斑块密度降低,存在局部连片情形;白河流域沼泽湿地面积增加,适宜地形和水文条件下,草甸湿地和周边草甸可转为沼泽湿地;两河流域湿地变化具有“社会经济+农牧业因素+气候变化”交互作用的特征,社会经济类因素对年代际尺度湿地变化起主导作用。

By constructing the decision tree model,the main wetland types such as swamp meadow wetland,swamp wetland and lake in Heihe River and Baihe River basins was divided.Three landscape pattern indices were selected to analyze the change characteristics of wetland types,and the driving factors of wetland change were analyzed by principal component analysis.The results show that the total area of wetlands in Heihe River and Baihe River basins has increased since 2000,and the change trend of swamp wetlands is opposite to that of meadow wetlands.The regional differences of wetland changes in the two river basins are significant.In the Heihe River Basin,the area of meadow wetland increases with the reduction of the fragmentation degree.And the area of swamp wetland decreases with the patch density reducing,and there is local contiguity.In Baihe River Basin,the area of swamp wetland increases.Under suitable topographic and hydrological conditions,meadow wetland and surrounding meadow can be transformed into swamp wetland.The wetland change in the two river basins has the interactive characteristics of“socio-economic+agricultural and animal husbandry factors+climate change”,and socio-economic factors play a leading role in the interdecadal scale wetland change.