1973-2020年黄河三角洲滨海盐沼湿地景观格局演化模式和驱动因素OACHSSCDCSTPCD

Understanding the dynamics and driving factors of the coastal salt marsh landscape patterns is critical for effective wetland restoration and sustainable development of the regional ecosystem.This study aims to investigate the spatiotemporal evolution and the driving factors of the salt marsh landscape patterns in the coastal wetlands in the Yellow River Delta.First,we obtained the land use/cover maps during ten periods from 1973 to 2020 based on Landsat series satellite images,based on which we analyzed the spatiotemporal variations of the spatial extent of salt marshes and the conversion between salt marshes and other land use/cover types.We then adopted an improved State-and-Evolution Detection models(SEDMS)to analyze the landscape pattern evolution characteristics of salt marshes and utilized the geographic detector to analyze the driving factors of the spatial variation.The results showed that:(1)from 1973 to 2020,the area of salt marshes decreased by 252.35 km2,and the spatial extent moved seaward and tended to be concentrated.The lost salt marshes were mainly converted to grassland,aquaculture ponds,salt pans,and cultivated lands,while the restored salt marshes were mainly converted from tidal flats and unutilized land,water bodies.(2)The evolution of the salt marsh landscape showed obvious three stages:the unstable period from 1973 to 1995,during which the landscape pattern change types were dominated by disappearance and fragmentation;the transitional period from 1995 to 2010,during which the landscape pattern change types gradually transitioned from disappearance/fragmentation-dominated to expansion-dominated;the stable period after 2010,during which the area with landscape pattern change were relatively small,and the landscape pattern change types were dominated by emergence and expansion.(3)Nearly 36％of the salt marsh wetlands experienced multiple alterations in landscape pattern change types.The tidal flats and unutilized land,cultivated land had the most significant influence on the frequency of landscape pattern changes and the artificial surface,aquaculture ponds/salt pans,road and dams led to the fragmentation and disappearance of salt marsh wetlands.