Research On Spatiotemporal Changes Of Coastal Wetland Landscape Pattern And Ecosystem Service Value Based On Remote Sensin

Wetlands,as an important component of natural systems,play an important role in the global carbon cycle,providing humanity not only with abundant food,raw materials,and water resources,but also with the maintenance of ecological balance,biodiversity,and scarce species resources,as well as water conservation,flood prevention,pollution degradation,climate regulation,groundwater replenishment,and soil erosion.However,under the influence of large-scale human development,the world’s wetlands have been degraded or even disappeared.Wetland monitoring and protection is urgent.Acquiring accurate spatial distribution information of wetlands is the basis of wetland conservation and management.Remote sensing technology with its broad observational range,abundant information,rapid access to information,and high comparability plays an important role in dynamic real-time monitoring of wetland land cover change and has been used extensively in research on wetland resource surveying and wetland identification over the past few years.By strengthening remote sensing monitoring and research of wetlands and correctly grasping the distribution and dynamic trends of wetlands of all types,we can provide scientific decision-making support for wetland protection,management and wetland ecological restoration,and make wetland resources sustainable.The marine wetland is recognized as the "kidney of the earth",yancheng’s coastal wetlands are a national nature reserve,a national marine seed resource reserve,and a major source of water,as well as habitat for rare and threatened birds and other animals.This study uses satellite data as data source,chooses the coastal wetland reserve in Yancheng,Jiangsu province,as research area,classifies the wetland land cover types in the study area by supervision and classification,especially realizes the detailed division of the vegetation types in the study area,and analyzes the dynamic change law of the coastal wetland in Yancheng city by combining the image data over the years,in order to provide some reference basis for wetland protection and scientific utilization.At the same time,the spatial and temporal changes of landscape pattern and ecological service value in the study area were analyzed from the perspective of landscape pattern and ecological service value using GIS and landscape pattern index.The main conclusions were as follows:(1)In this study,the types of coastal wetland in Yancheng were divided into six categories: alkaline tent,rice grass,reed,water body,construction land and paddy field.A comprehensive analysis of relevant wetland data in the study area showed that the total area of coastal wetlands in Yancheng decreased from 1985 to 2020.The largest decrease was in the area of alkaline ponds,from 10,756.48 hm2 in 1985 to 5,278.83 hm2 in 2020,followed by water bodies,from 4,024.86 hm2 in 1985 to 1,113.86 hm2 in 2020,with the largest increase in the area of reciprocal flowering mead wetlands,by 3,078.30 hm2.According to the analysis of 17 landscape pattern indices of landscape type and landscape level,the fragmentation of coastal wetland landscape in salt city increased from 1985 to 2020,the structure of landscape type tended to be complicated,and the Shannon diversity index and Shannon uniformity index generally increased over the 35 years.(2)From 1985 to 2020,the total value of ecosystem services of the coastal wetland in Yancheng decreased year by year,reaching a high of 8.483 billion yuan in 1985 and 3.972 billion yuan in 2020.In terms of the value of wetland ecosystem services in different wetland landscape types,the value of alkaline canopy,flowering rice grass and water body all showed a downward trend.Reeds,paddy fields all showed an upward trend.The value of construction land was ignored and not accounted for.The most significant decrease was in the value of reciprocal flowering rice and grass,which decreased by 1.21 billion yuan.In proportion,the dominant landscape in the study area was reed,alkaline tent,and cross-flowering rice grass.For different wetland ecosystem services value dimensions,the four main types of service value order were regulation services > support services > supply services > cultural services,and water temperature regulation and biodiversity conservation were given as the main service functions in the study area.(3)The total value of ecosystem services in Yancheng Marina wetlands was negatively correlated with their patch density,landscape segmentation,Shannon diversity index and Shannon uniformity index,while their boundary density was negatively correlated with their spread index,indicating that the higher the landscape fragmentation of wetland types and the more complex the patch shape,the less the value of the wetland ecosystem services in the study area,and the greater the size and aggregation of the dominant landscape types,the value of wetland ecosystem services in the study area increased.