Landscape Features And Optimization Of Ecological Security Pattern In The Source Area Of Fenhe River Basin

The optimization of ecological security pattern could improve ecosystem services,maintain ecosystem stability and restore the original ecological functions of ecosystems.It is an important spatial way to solve ecological environment problems and ensure regional ecological security.The source area of the Fenhe River Basin is located in the loess hilly and gully area.The land is fragmented,the natural conditions are harsh,and the ecological environment is fragile.In addition,Ningwu and Jingle counties are deep poverty-stricken counties,and the level of economic development is low.The important reason for deep poverty is that the regional ecological environment is fragile and the ecological environment is also one of the main factors causing deep poverty.Therefore,in order to resolve the contradiction between ecological protection and economic development,we must pay attention to the ecological protection and restoration plan.The identification of ecological source and nodes in the ecological security pattern,the construction of ecological corridors and the determination of ecological breakpoints have identified key areas for ecological protection and restoration construction,with a view to providing spatial guidance for regional ecological protection and restoration planning.In this context,this paper takes the source region of the Fenhe River Basin as an example,analyzes spatial pattern of ecological land use and ecosystem service.And minimum cumulative resistance model is adopted to identify ecological security pattern,and hot spot analysis is used to identify important ecological sources.On the aspect of the setting of the resistance surface,on the one hand,considering the excessive width of the river,it has greatly hindered the migration activities of certain biological species,and constructed a mode-resistance surface.On the other hand,the river promoted the construction of the wetland ecological environment greatly.The important habitat of wetland organisms;On this basis,the ecological corridors were extracted separately,and the ecological security pattern of the source area of the Fenhe River Basin was studied,and relevant suggestions were put forward.The research conclusions were as follows:(1)Forest land,grassland,cultivated land,garden land and water area were extracted from the land use status database as ecological land,and particle size analysis method was used to generate particle size raster maps of different grades between 30and 300 m at intervals of 30 m.The landscape index was selected at the type level and the landscape level for analysis.The final determination of the 90m grain size and the800m range was the most suitable scale for studying the landscape pattern.The comprehensive analysis showed that there are serious problems such as serious landscape fragmentation and poor landscape connectivity in some areas.(2)This paper was based on the water production module and biodiversity protection module in the InVEST model,and used the modified general equation of soil erosion,quantitative assessment of water production,habitat quality,and soil conservation ecosystem services.We draw a conclusion that the yield of the study area was 7.65×10~8m~3;the average habitat quality index reached 0.84,which was divided into 0~0.3,0.3~0.6,0.6~0.9,0.9~1.0,and the area ratio was 1.3%,0.8%,43.4%,54.5%;There were serious ecological problems of soil erosion,and it was necessary to carry out ecological protection and restoration of the area to improve its ecological functions.(3)There are 19 ecological sources in the source area of the Fenhe River Basin,accounting for 16.59%of the total area of the study area.Based on the two modes of resistance,33 and 42 ecological corridors were constructed respectively,and the comprehensive ecological corridors were 43.The lengths of the corridors were363.811km,556.423km and 565.957km respectively.The network structure evaluation results showed that the network closure was between 0.455 and 0.758,the node connection rate was between 1.737 and 2.263,the network connection was between0.647 and 0.843,and the cost ratio was between 0.909 and 0.924.The connection rate and network connectivity were relatively high,and the cost was relatively small.All three modes could generate a closed ecological network.In addition,a total of 35ecological breakpoints have been identified and engineering or biological measures must be taken to protect biodiversity.