| High-intensity human activities have a greater impact on regional hydrology and water cycle processes,and problems such as water shortages,water disasters,and the loss of aquatic habitats are becoming more and more serious.The regional human-water balance and sustainable development can be realized by identifying key areas in the water ecosystem,rationally constructing the pattern of water ecological security,and planning the regional water ecological space,which also maintenance the functions and structure of water ecosystems.Based on the theories of landscape ecology,landscape architecture and urban planning,with the help of GIS,RS and SPSS platform,this paper evaluated the importance for five kinds of water ecosystem service functions in Linli County,Hunan Province,such as water conservation,water and soil conservation,biological protection in water ecological space,flood regulation and storage,and water quality purification.The comprehensive materiality evaluation results were analyzed by MSPA and landscape connectivity,combined with MCR and circuit theory,to construct a water ecological security pattern.On this basis,the water ecological space was demarcated,and finally the water ecological space protection strategies were proposed from the level of"point-line-surface".The main findings are as follows:(1)Functional importance assessment of aquatic ecosystem services.The areas with extremely important and highly important of integrated water ecosystem service functions are 15 066.63 hm2 and 25 538.22 hm2 respectively,accounting for 12.58%and 21.31%of the total area of Linli County,which are centrally distributed in the Lishui River,the Daoshui National Wetland Park,the Taifushan Scenic Spot,the Guanting Reservoir and other areas.Small and medium-sized reservoirs and their surrounding areas are distributed in dots.These areas are rich in vegetation,rich in water sources,and have high water ecological value,which is an important component of maintaining regional water ecological security,and their water ecological balance should be maintained.The important area is 19 700.01 hm2,accounting for 16.44%of the total area of Linli County,which is distributed around the extremely important and highly important areas,and the construction of water ecological infrastructure should be strengthened.The general important areas have the largest areas,occupying 34 695.27 hm2,accounting for 28.95%of the total area of Linli County,which are not obviously concentrated.The unimportant areas have a total area of 24 831.99 hm2,accounting for 20.72%of the total area of Linli County,and the areas distribute in the central urban area and the cultivated land area in the north,which has low vegetation coverage,low water ecological value and serious human interference.(2)Construction of water ecological security pattern.Linli County has a large number of water ecological source patches,with a total area of 3 531.71 hm2,accounting for 2.93%of the total area of Linli County.There are 30 water ecological source patches,including Lishui River,Daoshui River,Guanting Reservoir,Qunying Reservoir,Tonghuan Reservoir,and Fushan Reservoir,among which Lishui is the most important one,followed by Guanting Reservoir.The buffer zone of water ecological is divided into five safety levels:lowest,lower,medium,higher and highest.Among them,the pattern of lowest safety level is around the core water ecological source area,which covers an area of 20212.92 hm2,accounting for 16.82%of the total area of Linli County,and is extremely unsuitable for urban construction.The area of the lower safety level area is 24 939.54 hm2,accounting for 20.75%of the total area of Linli County,and this part is closely surrounding the area of the lowest safety level.The area with medium safety level is located between the higher and lower safety level areas,with an area of 41 349.42 hm2,accounting for 34.41%of the total area of Linli County,which is a transitional area between water ecological protection and urban development and construction.The areas of the highest safety level and the higher safety level are 4 357.08 hm2 and 29 305.17 hm2 respectively,accounting for 3.63%and 24.39%of the total area of Linli County,which is a high resistance area for the diffusion of water ecological sources and an important area for carrying regional production and living functions.At the same time,29 water corridors with a total length of 213.02 km are identified by cost connectivity.66 water corridors are identified by Linkage Mapper,showing the characteristics of north-sparse-south-dense.Each water ecological source patches are connected by water ecological corridors and formed network loop.(3)Water ecological spatial division.The total area of comprehensive water ecological space is 51 892.26 hm2,accounting for 43.31%of the total area of Linli County.And the water ecological space delineated based on the level of water ecological security basically covers the scope of delineation according to the importance of water ecosystem service functions.Water ecological space is divided into three categories:the core area,buffer zone and control area of water ecological space.Among them,the proportion of water and forest land in the core area of water ecological space is as high as 92.26%;The main land use types in the buffer area and control area of water ecological space are forest land,accounting for 45.24%and 47.96%of the total area of each district,respectively.Water ecological space is mainly based on ecological land such as water areas and woodlands,indicating that the demarcation results are relatively reasonable.Furthermore,according to the elements of water ecological security pattern,the protection strategies of water ecological space in Linli County are proposed.①Taking "keeping the blue,preserving the blue,and introducing the blue" as the protection strategy of the water ecological source,it can expand the area of the water ecological source and enhance its connectivity.②We should give priority to the protection and restoration of water ecological grips and obstacles in the core area of water ecological space,and propose corresponding protection and restoration strategies according to the landscape types of these key areas.③We also ought to construct a water ecological space protection corridor with a certain width to connect various water ecological sources.Vegetation buffer zones,planting ditches and constructed wetlands with interception effects shall be established within a certain width along the aquatic ecological blue line corridor;The aquatic ecological green line corridor adopts indigenous tree species to green bare land,and constructs a composite three-dimensional space structure including qiao,shrub and grass.④A blue-green intertwined "one axis,two belts,five waters,multiple points" water ecological space network should be constructed,which can plan and protect the water ecological space from a systematic perspective.The research results can provide a certain reference for the planning of water ecological space and landscape architecture in the county. |
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