Wetland landscape pattern change and its driving forces in Beijing-Tianjin-Hebei region in recent 30 years

Wetlands,which are among the most productive and biodiverse ecosystems on Earth,are areas where aquatic and terrestrial ecosystems converge.Wetland environments are threatened by the rapid urbanization and socio-economic development of the Beijing-Tianjin-Hebei region.In this study,we analyzed the changes in the wetland landscape and its driving forces in the Beijing-Tianjin-Hebei region following GIS and principal component analysis methods.The results are as follows:(1) From the late 1980 s to 2015,the wetland area slightly increased and then rapidly decreased,however this decreasing trend slowed slightly over the last ten years.The wetland area of the Beijing-Tianjin-Hebei Region decreased by2695.05 km2,a reduction of 20.08%.The largest reduction occurred in Hebei Province,which is dominated by natural wetlands,followed by Tianjin and Beijing City.(2) Wetland areas were mainly lost in Bohai Bay,Beijing City,and the Zhangjiakou and Tangshan Cities of Hebei Province.(3) Paddy,reservoir,and pond wetlands are the dominant landscapetypes.Fragmentation is serious and the degree of aggregation is low in lake,river and canal,and beach landscapes,indicating that the spatial distribution of wetlands is discrete with poor connectivity.(4) The driving forces were analyzed using nine indicators following the principal component analysis method.The result showed that human activities were the main driving forces,and urban expansion and agricultural development were the main pathways of degradation.Additionally,the wetland landscape is also influenced by policy and the climate.