Construction And Optimization Simulation Of Wetland Ecological Network In The Yellow River Estuary

In recent years,due to the influence of human activities and changes in the natural environment,the internal evolution of the Yellow River estuary wetland has been violent.The quality of the habitat has continued to decline.The fragmentation of the habitat has intensified.All of these affected the safety and stability of the ecosystem.Based on the theory of landscape ecology,GIS spatial analysis and other methods,this research took the Yellow River estuary as the research object,and analyzed the evolution of the landscape area of the Yellow River estuary from 1991 to 2020 and the reasons for evolution.This research used the minimum cost distance model to comprehensively consider the multi-factor resistance to construct the Yellow River estuary wetland ecological network,and the ecological network is evaluated from the aspects of network landscape composition,network structure,key nodes and ecological break points,and the average biomass of macrobenthos in the ecological network.With the goal of improving the food supply capacity of the Yellow River estuary wetland,the ecological network is optimized for both the habitat source and the resistance area.An optimized ecological network of the Yellow River estuary wetland was constructed,the overall function of the Yellow River estuary wetland has been improved.The main conclusions are:(1)Under the influence of natural and human factors such as storm surge,coastal erosion,water and sediment regulation,agricultural planting,artificial facilities and invasion of Spartina alterniflora,the natural wetland landscape area in the study area decreased year by year from 1991 to 2020,among which the area of herb swamp and shrub wetland decreased most obviously,and the area of non natural wetland increased year by year,mainly the growth of paddy field,aquaculture pond and salt field.In the Yellow River estuary,the total length and density of wet land tidal channel decreased,and the hydrological connectivity decreased year by year.The connectivity of the entire natural wetland landscape of the Yellow River estuary has declined year by year,the connection between habitat patches has become more difficult,and the fragmentation of the natural wetland landscape has increased.(2)Through the selection of the habitat source of the Yellow River estuary and the determination of the comprehensive resistance surface,an ecological network of the Yellow River estuary wetland has been formed.The study found that: Salt marsh wetlands,herbaceous swamps and shrub wetlands are the dominant landscapes that constitute the ecological network,and unnatural wetlands account for a relatively small proportion of the potential ecological network;The network structure index is at a medium level;Most of the key nodes in the Yellow River estuary ecological network are located in intertidal wetlands that play an important role in the migration of species.There are many road break points and hydrological connection break points.The average biomass of macrobenthos in the ecological corridor is relatively low.The ecological network of the Yellow River estuary Wetland needs to be further optimized.(3)The ecological network of the Yellow River estuary wetland was optimized from two aspects: habitat source and resistance surface.The fragmented landscape patches were combined,the joint nodes were optimized and the ecological break points were eliminated.The optimized ecological network of the Yellow River estuary wetland was constructed.The importance of patches and macrobenthics biomass were used as indicators for selecting habitat sources,landscape classification and the distribution of macrobenthics biomass in the Yellow River estuary were used as resistance factors to construct resistance surfaces to generate an optimized ecological network.Through comparison,we found: Through the optimized construction of the Yellow River estuary wetland Ecological Network,the area of salt marsh wetlands in the Yellow River estuary ecological network has increased,the structure of the ecological network is better than before,and the number of corridors and nodes have both increased;The average biomass of macrobenthos in the ecological network has been improved,which is conducive to the development of the food supply capacity of the Yellow River estuary wetland;after optimization,the landscape connectivity between the natural wetland of the Yellow River estuary and the ecological network has been improved.The optimal construction of ecological network reduces the impact of habitat fragmentation.