A method for constructing an urban blue-green ecological network based on composite functions

Abstract

The present application relates to a kind of urban blue-green ecological network construction method based on composite function, comprising: obtaining the spatial distribution data of the present situation blue-green patch of object area, and screening target ecological source area;Build the comprehensive resistance surface of urban blue-green space, simulate the minimum resistance path of potential ecological corridor based on MCR model;Select target ecological source area and comprehensive resistance surface, calculate the current adjacent centrality of each minimum resistance path, obtain blue-green corridor importance classification;Select multiple-to-one calculation mode, and identify current density distribution map;Extract suitable corridor width range map and ecological pinch point distribution map;Target ecological source area, blue-green corridor importance classification, suitable corridor width range map and ecological pinch point distribution map are superimposed, and the construction of urban blue-green ecological network is completed.The construction of urban blue-green ecological network is carried out by the present application, and it has important value for protecting urban biodiversity, adjusting heat island effect, improving urban livability and meeting the daily recreational needs of residents.

Description

Technical Field

[0001] This invention relates to the field of urban ecological planning and construction technology, specifically to a method for constructing an urban blue-green ecological network based on composite functions. Background Technology

[0002] In recent years, rapid urban development has strongly promoted economic development, but it has also led to a series of ecological and environmental problems such as deteriorating air quality, habitat fragmentation, and reduced biodiversity. At the same time, rapid development has also been accompanied by many negative impacts on water systems, such as deterioration of water quality and environment, decrease in water surface area, and reduced water system connectivity.

[0003] To enhance urban resilience and reshape the harmonious relationship between humans and nature, people have begun to integrate ecological planning, green space planning, and water resource management at the urban planning level, giving rise to the urban blue-green ecological network. This network combines urban green spaces, woodlands, wetlands, and water bodies, helping to protect urban biodiversity, mitigate the urban heat island effect, improve urban livability, and meet residents' daily recreational needs.

[0004] Currently, most domestic and international methods for constructing ecological networks are aimed at large-scale areas and primarily focus on protecting biodiversity. However, urban blue-green ecological networks are geared towards urban areas and face more complex ecological and environmental problems, more diverse components, and more complex functional requirements. Existing methods for constructing ecological networks cannot adequately balance the needs of urban ecological protection and human ecological livability. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method for constructing an urban blue-green ecological network based on composite functions. This method constructs an ecological network based on urban blue-green patches, thereby forming an urban ecological security pattern while meeting the needs of human ecological livability.

[0006] The technical objective of this invention is achieved through the following technical solution:

[0007] A method for constructing a multi-functional urban blue-green ecological network, comprising:

[0008] Step 1: Obtain spatial distribution data of existing blue-green patches in the target area, and select candidate ecological source areas from green space and water body patches according to the set area threshold.

[0009] Step 2: Construct an evaluation index system for ecological source areas based on the composite functions of urban blue-green spaces. Use the evaluation index system to screen candidate ecological source areas and obtain target ecological source areas.

[0010] Step 3: Construct a comprehensive resistance surface for urban blue-green spaces, which includes a land use type resistance surface, a population density resistance surface, a distance resistance surface from major rivers, and a vegetation quality resistance surface.

[0011] Step 4: Select the target ecological source area and comprehensive resistance surface, and simulate the minimum resistance path of potential ecological corridors based on the minimum cumulative resistance model;

[0012] Step 5: Based on circuit theory, select the target ecological source area and the comprehensive resistance surface, calculate the current proximity centrality of each minimum resistance path, and classify the priority of ecological corridors and target ecological source areas according to the magnitude of current proximity centrality to obtain the importance classification of blue-green corridors.

[0013] Step 6: Based on circuit theory, input the target ecological source area and the comprehensive resistance surface into the Pinchpoint Mapper model, select the many-to-one calculation mode, set the cost-weighted distance as the threshold, identify the high current density area in the ecological corridor, and obtain the current density distribution map; extract the area with the highest current density as the width range of the ecological corridor, and obtain the suitable corridor width range map; extract the area with the highest current density as the ecological pinch point area range, and obtain the ecological pinch point distribution map.

[0014] Step 7: Overlay the target ecological source area, blue-green corridor importance classification, suitable corridor width range map and ecological splice distribution map to complete the construction of the urban blue-green ecological network.

[0015] Furthermore, in step 1, the green space patch data includes park green space, protective green space, ancillary green space and regional green space; the water body patches include river surface, lake surface, reservoir surface, pond surface, coastal mudflat, inland mudflat and ditch.

[0016] Furthermore, in step 1, the aggregated blue-green patches are screened according to a set area threshold to obtain candidate ecological source areas.

[0017] Furthermore, in step 2, the evaluation index system for ecological source areas includes a social service function system and an ecological service function system. The evaluation factors for the social service function system include source area and source accessibility, while the evaluation factors for the ecological service function system include habitat quality and connectivity importance.

[0018] Furthermore, the Analytic Hierarchy Process (AHP) was used to assign weights to all evaluation factors in the ecological source area evaluation index system. Based on the GIS platform, each factor was calculated separately to obtain a raster layer for each factor. The raster layers were superimposed and weighted for calculation. The results were reclassified to obtain the composite functional importance level of each patch. A threshold was set to screen target ecological source areas with higher importance levels.

[0019] Furthermore, in step 4, the minimum cumulative resistance model is expressed as follows:

[0020]

[0021] Where i represents the i-th landscape unit, j represents the j-th target ecological source area, m represents the total number of landscape units, n represents the total number of target ecological source areas, and D ij R represents the spatial distance between the j-th target ecological source area and the i-th landscape unit. i Let f represent the resistance value corresponding to the i-th landscape unit, and let f represent the positive correlation between the minimum cumulative resistance and the ecological process.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. In selecting the source site, this invention fully considers the combination of social and ecological functions, taking into account the needs of urban ecological protection and human ecological livability for building an urban blue-green ecological network.

[0024] 2. When constructing the comprehensive resistance surface and extracting the corridor path, we should fully consider the human need for slow recreation and the ecological conservation function of each ecological land. We should combine the current land use with other resistance surfaces and select the resistance surface based on the characteristics of blue-green space, namely the resistance surface based on the distance from the river and the resistance surface based on the vegetation coverage. The resistance surface based on the distance from the main river can allow the corridor to pass through the waterfront space on both sides of the main river, while the resistance surface based on the vegetation coverage can allow the corridor to pass through the green space with high vegetation coverage.

[0025] 3. In addition to the path with the minimum cumulative resistance, the importance of each corridor and source area to the entire ecological network is calculated by introducing proximity centrality analysis, which helps to classify blue-green corridors.

[0026] 4. Based on current theory, high current density areas in the blue-green ecological corridor are identified. Areas with different current density thresholds are taken as the suitable path space range and ecological pinch point range of the blue-green corridor. The suitable path space range is used as a reference for the corridor width range, and the ecological pinch points are used for key protection to improve the feasibility of the planning and construction of the scheme.

[0027] 5. This invention addresses the complex and diverse environmental problems within cities by constructing a blue-green integrated ecological network. It fully utilizes fragmented ecological spaces within cities, balances the needs of urban ecological protection and human ecological livability, and fulfills the goal of blue-green synergy in urban ecological construction and protection, thus possessing significant practical value. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the construction process of the urban blue-green ecological network based on composite functions according to the present invention.

[0029] Figure 2 This is a distribution map of urban blue-green ecological source areas in an embodiment of the present invention.

[0030] Figure 3 This is a comprehensive resistance surface distribution diagram in an embodiment of the present invention.

[0031] Figure 4 This is a potential blue-green corridor distribution map in an embodiment of the present invention.

[0032] Figure 5 This is a blue-green corridor importance classification diagram in an embodiment of the present invention.

[0033] Figure 6 This is a current density diagram in an embodiment of the present invention.

[0034] Figure 7 This is a diagram showing the suitable corridor width range in an embodiment of the present invention.

[0035] Figure 8 This is a distribution map of ecological pinch points in an embodiment of the present invention.

[0036] Figure 9 This is a schematic diagram of the blue-green ecological network in an embodiment of the present invention.

[0037] Figure 10 This is the present invention. Figure 9 Enlarged view of point b in the image.

[0038] Figure 11 This is the present invention. Figure 9 Enlarged view of point c in the image. Detailed Implementation

[0039] The technical solution of the present invention will be further described below with reference to specific embodiments:

[0040] A method for constructing an urban blue-green ecological network based on multiple functions, such as Figure 1 As shown, the method includes:

[0041] Step 1: Obtain the spatial distribution data of blue-green patches in the target area. The spatial distribution data of blue-green patches includes green space patch data and water body patch data. Among them, green space patch data includes park green space, protective green space, attached green space and regional green space; water body patch green space includes river surface, lake surface, reservoir surface, pond surface, coastal mudflat, inland mudflat and ditch.

[0042] To consolidate the overly fragmented blue-green patches, the aggregation surface tool in GIS software is used to aggregate green space and water body patches within a certain range.

[0043] The data packages of green patches and water patches are aggregated to form blue-green patches. The aggregated blue-green patches are then screened according to a set area threshold to select candidate ecological source areas.

[0044] Step 2: Construct an ecological source area evaluation index system based on the composite functions of urban blue-green spaces, including a social service function system and an ecological service function system. The evaluation factors of the social service function system include source area and source area accessibility, while the evaluation factors of the ecological service function system include habitat quality and connectivity importance. The values ​​are assigned using the method in Table 1.

[0045] Based on the socio-economic level and natural geographical conditions of the study area, taking Minhang District of Shanghai as an example, the Analytic Hierarchy Process (AHP) was used to assign weights to all evaluation factors in the ecological source area evaluation index system. Based on a GIS platform, each factor was calculated separately, resulting in raster layers for each factor. These raster layers were then weighted and overlaid for analysis. The analysis results were reclassified to obtain the composite functional importance level of each patch. In this embodiment, the importance level was divided into 10 levels (1-10). A screening threshold was set to select candidate ecological source areas with higher importance levels as target ecological source areas. Figure 2 As shown.

[0046] Table 1. Screening Index System for Urban Blue-Green Ecological Source Areas Based on Socio-Ecological Composite Functions

[0047]

[0048] Step 3: Construct a comprehensive resistance surface for urban blue-green spaces; combine the current land use in Minhang District with other resistance factors to construct a resistance factor table (Table 2). This table mainly includes four resistance factors: land use, population density, distance from major rivers, and vegetation coverage.

[0049] The land use resistance surface includes various types of land use such as green spaces, water bodies, and construction land, which are assigned resistance values. Among them, ecological land such as green spaces and water bodies are assigned smaller values, while non-ecological land such as construction land is assigned larger values. The population density resistance surface uses mobile phone signaling heat maps at specific time points, which are then classified and assigned resistance values. The higher the heat map value, the greater the resistance value. The distance from the main river resistance surface is designed to ensure that the corridor travels along the green spaces surrounding the blue space of the main river. The Euclidean distance from each pixel to the main river is calculated using the main river vector map, and then classified and assigned resistance values. The closer to the river, the smaller the resistance value. The vegetation coverage is designed to ensure that the corridor travels along green spaces with high vegetation coverage. The summer normalized vegetation index (NDVI) map is used to classify and assign resistance values. The higher the index, the smaller the resistance value (Table 2).

[0050] Using the Analytic Hierarchy Process (AHP), weights were assigned to the above indicators, resulting in a resistance factor table (Table 2). Based on GIS software, the raster layers of each resistance factor were spatially weighted and overlaid using these indicator weights to determine the comprehensive resistance surface raster map, as shown below. Figure 3 As shown.

[0051] Table 2. Resistance Factor Assignment Table

[0052]

[0053]

[0054]

[0055] Step 4: Select the target ecological source area and comprehensive resistance surface, and simulate the minimum resistance path of the potential ecological corridor based on the minimum cumulative resistance (MCR) model. The minimum cumulative resistance model is expressed as follows:

[0056]

[0057] Where i represents the i-th landscape unit, j represents the j-th target ecological source area, m represents the total number of landscape units, n represents the total number of target ecological source areas, and D ij R represents the spatial distance between the j-th target ecological source area and the i-th landscape unit. i Let represent the resistance value corresponding to the i-th landscape unit, and f represent the positive correlation between minimum cumulative resistance and ecological processes. The MCR model can simulate the potential corridor path with the shortest cost-weighted distance (CWD) between two source areas, such as... Figure 4 As shown.

[0058] Step 5: Based on circuit theory, select the target ecological source area and the comprehensive resistance surface, and calculate the current flow betweenness centrality (CFBC) for each minimum resistance path in Step 4. Circuit theory treats the landscape surface as a conductive surface, using the random flow of electrons in a circuit to simulate the migration and diffusion process of an individual species or gene in the landscape. CFBC can be used to measure the importance of a path and a source area in maintaining the connectivity of the entire ecological network, and can be used to determine the priority of corridors constructed based on that path.

[0059] In GIS software, based on the Centrality Mapper model, the target ecological source area and the comprehensive resistance surface are input, and the process is run to identify the current density between ecological corridors and target ecological source areas, generating centrality data for each ecological corridor and target ecological source area. Then, based on the centrality value of each ecological corridor and source area, they are classified to obtain an importance classification map of all ecological corridors and target ecological source areas based on centrality analysis, i.e., the importance classification of blue-green corridors, such as... Figure 5 As shown.

[0060] Step 6: Based on circuit theory, input the target ecological source area and the comprehensive resistance surface into Pinchpoint Mapper, and select the many-to-one calculation mode. This process involves grounding one ecological patch on the landscape surface, inputting a 1A current to all other patches, calculating the current values ​​from all patches to the grounded patch, and obtaining the current density map in the many-to-one mode through iterative calculation; setting the cost-weighted distance as a threshold, identifying high current density areas in the ecological corridor, and obtaining the current density distribution map, such as... Figure 6 As shown; the region with the highest current density (top 50%) is extracted as the width range of the ecological corridor (i.e., the width of the blue-green corridor), resulting in a suitable corridor width range map, as shown. Figure 7 As shown; the region with the highest current density (top 25%) is extracted as the ecological pinch area, resulting in an ecological pinch distribution map, as shown. Figure 8 As shown, ecological clips are used for key protection;

[0061] Step 7: Overlay the maps of target ecological source areas, blue-green corridor importance classification, suitable corridor width range, and ecological junction distribution to complete the construction of the urban blue-green ecological network, forming... Figure 9-11 The diagram illustrates a blue-green ecological network. This network clearly demonstrates the importance of blue-green source areas and corridors, the appropriate width range of corridors, and key protected areas. It provides a reference for guiding the construction priorities, scope, and key protected areas of blue-green corridors in urban ecological construction and protection.

[0062] This embodiment is merely a further explanation of the present invention and is not intended to limit the present invention. Those skilled in the art can make non-inventive modifications to this embodiment as needed after reading this specification, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A method for constructing an urban blue-green ecological network based on composite functions, characterized in that, The method includes: Step 1: Obtain spatial distribution data of existing blue-green patches in the target area, and select candidate ecological source areas from green space and water body patches according to the set area threshold. Step 2: Construct an evaluation index system for ecological source areas based on the composite functions of urban blue-green spaces. Use the evaluation index system to screen candidate ecological source areas and obtain target ecological source areas. Step 3: Construct a comprehensive resistance surface for urban blue-green spaces, which includes a land use type resistance surface, a population density resistance surface, a distance resistance surface from major rivers, and a vegetation quality resistance surface. Step 4: Select the target ecological source area and comprehensive resistance surface, and simulate the minimum resistance path of potential ecological corridors based on the minimum cumulative resistance model; Step 5: Based on circuit theory, select the target ecological source area and the comprehensive resistance surface, calculate the current proximity centrality of each minimum resistance path, and classify the priority of ecological corridors and target ecological source areas according to the magnitude of current proximity centrality to obtain the importance classification of blue-green corridors. Step 6: Based on circuit theory, input the target ecological source area and the comprehensive resistance surface into the Pinchpoint Mapper model, select the many-to-one calculation mode, set the cost-weighted distance as the threshold, identify the high current density area in the ecological corridor, and obtain the current density distribution map; extract the area with the highest current density as the width range of the ecological corridor, and obtain the suitable corridor width range map; extract the area with the highest current density as the ecological pinch point area range, and obtain the ecological pinch point distribution map. Step 7: Overlay the map of the target ecological source area, the importance classification of blue-green corridors, the suitable corridor width range, and the distribution map of ecological junctions to complete the construction of the urban blue-green ecological network; In step 2, the ecological source area evaluation index system includes a social service function system and an ecosystem service function system. The evaluation factors of the social service function system include source area area and source area accessibility, while the evaluation factors of the ecosystem service function system include habitat quality and connectivity importance. The Analytic Hierarchy Process (AHP) was used to assign weights to all evaluation factors in the ecological source area evaluation index system. Based on the GIS platform, each factor was calculated separately to obtain a raster layer for each factor. The raster layers were superimposed and weighted, and the results were reclassified to obtain the composite functional importance level of each patch. A screening threshold was set to select target ecological source areas with higher importance levels.

2. The method for constructing a multi-functional urban blue-green ecological network according to claim 1, characterized in that, In step 1, the green space patch data includes park green space, protective green space, attached green space and regional green space; the water body patches include river surface, lake surface, reservoir surface, pond surface, coastal mudflat, inland mudflat and ditch.

3. The method for constructing an urban blue-green ecological network based on composite functions according to claim 2, characterized in that, In step 1, candidate ecological source areas are obtained by screening the aggregated blue-green patches according to the set area threshold.

4. The method for constructing an urban blue-green ecological network based on composite functions according to claim 1, characterized in that, In step 4, the minimum cumulative resistance model is expressed as follows: ， Where i represents the i-th landscape unit, j represents the j-th target ecological source area, m represents the total number of landscape units, and n represents the total number of target ecological source areas. This represents the spatial distance between the j-th target ecological source and the i-th landscape unit. This represents the resistance value corresponding to the i-th landscape unit. This indicates a positive correlation between minimum cumulative resistance and ecological processes.

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