An ecological network construction method for ecosystem multi-functionality synergistic effect

Abstract

The present application relates to the technical field of ecological network construction, and more particularly to an ecological network construction method for multi-function synergistic effect of ecological system; comprising the following steps: S1, setting multiple types of ecological system functions, and judging the relationship of any two ecological system functions; S2, calculating the multi-function synergistic effect potential value of each grid unit of the ecological system, and dividing the ecological protection area and the ecological restoration area; S3, constructing a random forest model, and screening out key factors from the influence factors; S4, taking the center point of the ecological protection area and the center point of the ecological restoration area as two types of nodes, taking the shortest connected path between the two types of nodes as an edge, and taking the variation gradient of the key factors as the attribute of the edge, and constructing an ecological network; S5, performing multi-function protection and restoration work; considering the synergistic / trade-off relationship between the multiple types of ecological system functions, quantifying the multi-function synergistic effect potential of the ecological system, and effectively distinguishing the key areas of ecological protection and restoration work.

Description

Technical Field

[0001] This invention relates to the field of ecological network construction technology, and in particular to a method for constructing ecological networks that are oriented towards multifunctional synergistic enhancement of ecosystems. Background Technology

[0002] Ecological networks are a common method for constructing ecological security patterns, evolving from an early focus on the single ecosystem function of biodiversity conservation to an emphasis on the multifunctionality of ecosystems. When constructing ecological networks based on ecosystem multifunctionality, the process typically begins by developing assessment indices for individual functions, followed by weighted summation of multiple functional indices to establish a comprehensive ecosystem function index. Areas with higher scores on this comprehensive index are then designated as ecological source areas. Next, factors such as habitat quality or human activities are selected as resistance factors to construct ecological factor resistance surfaces. Finally, ecological networks with a structure of "ecological source area - ecological corridor - ecological pinch point / barrier point" are constructed using methods such as the minimum cumulative resistance model and circuit theory for constructing ecological security patterns and protecting ecological functions.

[0003] However, the above method has three shortcomings:

[0004] (1) There are synergistic / trade-off relationships among the functions of various types of ecosystems in the region. The method of constructing the comprehensive index of ecosystem functions based on weighted summation ignores the trade-off relationship between ecosystem functions. For ecosystem functions that present a trade-off relationship, synergistic enhancement cannot be achieved.

[0005] (2) Although using areas with higher ecosystem function scores as ecological sources helps protect the existing ecosystem status, it is impossible to identify potential areas with multifunctional synergistic effects for ecological restoration and spatial pattern optimization aimed at synergistic effects of ecosystem functions.

[0006] (3) Although corridors in traditional ecological network construction achieve the connection of different ecological sources with minimal resistance, the early design of corridors was aimed at biodiversity conservation, that is, leaving migration paths for organisms with mobility. With the increase in attention to the types of ecosystem functions, most ecosystem functions are static and cannot be spontaneously and autonomously diffused with corridors, such as water conservation, food production and carbon sequestration. Therefore, the traditional meaning of corridors (protecting biodiversity by leaving migration paths for organisms) no longer exists for other ecosystem functions.

[0007] Therefore, there is an urgent need to provide a method for constructing ecological networks that is oriented towards the synergistic enhancement of multiple ecosystem functions. Compared with existing technologies, this method considers the synergistic / trade-off relationships between the functions of multiple types of ecosystems in a region, quantifies the potential for synergistic enhancement of multiple ecosystem functions, and effectively distinguishes the key areas of the work. Summary of the Invention

[0008] To address the technical problems existing in the prior art, this invention provides a method for constructing an ecological network that promotes multifunctional synergistic effects within an ecosystem.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] A method for constructing ecological networks that promote multifunctional synergistic effects within ecosystems includes the following steps:

[0011] S1. Divide the ecosystem region into multiple grid units, set multiple types of ecosystem functions, obtain the correlation coefficient of any two types of ecosystem functions, and determine the relationship between the two ecosystem functions, including synergistic and trade-off relationships.

[0012] S2. Select the ecosystem functions that exhibit synergistic relationships, calculate the potential value of ecosystem multi-functional synergistic enhancement for each grid cell, and divide the ecological protection zone and ecological restoration zone according to the potential value of ecosystem multi-functional synergistic enhancement.

[0013] S3. Each ecosystem function includes multiple influencing factors. All influencing factors of each grid cell are used as independent variables, and the corresponding potential value of synergistic enhancement of ecosystem functions is used as dependent variable. A random forest model is constructed, and key factors are selected from the influencing factors based on the random forest model.

[0014] S4. Take the center point of the ecological protection zone and the center point of the ecological restoration zone divided in step S2 as two types of nodes, take the shortest connecting path between two adjacent types of nodes as the edge, and define the variation gradient of the key factor on the connecting path as the attribute of the edge, thereby constructing an ecological network.

[0015] S5. Based on the ecological network constructed in step S4, multifunctional protection and repair work is carried out.

[0016] Furthermore, S1 specifically includes the following steps:

[0017] S11. Calculate the functional value of each ecosystem function;

[0018] S12. In each type of ecosystem function, sort all grid cell function values ​​from largest to smallest to obtain the sorted function value of each grid cell, and then calculate the correlation coefficient between each pair of ecosystem functions. When the correlation coefficient is greater than 0, it indicates that the two ecosystem functions are synergistic; when the correlation coefficient is less than 0, it indicates that the two ecosystem functions are trade-offs.

[0019] Furthermore, the correlation coefficient in step S12 is calculated using the following formula:

[0020] ;

[0021] In the above formula, Let represent the correlation coefficient between the i-th ecosystem function and the l-th ecosystem function, where i and l both take values ​​from 1 to N, and N represents the total number of ecosystem functions. This represents the ranking value of the j-th raster cell in the i-th ecosystem function. This represents the average of the sorted function values ​​of all raster cells for the i-th type of ecosystem function. This represents the ranking value of the j-th raster cell in the l-th ecosystem function. represents the average of the sorted function values ​​of all raster cells for the l-th type of ecosystem function, and n represents the total number of raster cells.

[0022] Furthermore, the potential value for multifunctional synergistic effects of the ecosystem in step S3 is calculated using the following formula:

[0023] ;

[0024] In the above formula, This represents the potential value for multifunctional synergistic effects of the ecosystem in the j-th grid cell. This represents the comprehensive development index of the j-th grid cell.

[0025] Furthermore, the comprehensive development index of the j-th grid cell is calculated using the following formula:

[0026] ;

[0027] In the above formula, Y represents the weight of the y-th ecosystem function exhibiting a synergistic relationship, and Y represents the total number of selected ecosystem functions exhibiting a synergistic relationship. Take 1, The standardized value of the function of the y-th ecosystem function that exhibits a synergistic relationship is represented.

[0028] Furthermore, based on the potential for synergistic effects of ecosystem multifunctionality, ecological protection zones and ecological restoration zones are delineated. The specific method is as follows: when... At that time, the grid unit represents an area with low potential for synergistic effects and is designated as an ecological protection unit; when At that time, the grid unit is an area with high potential for synergistic effect and is an ecological restoration unit; adjacent ecological restoration units are formed into ecological restoration areas, and multiple adjacent ecological protection units are formed into ecological protection areas.

[0029] Furthermore, the method for selecting key factors in step S3 is as follows: set a cumulative threshold, compare the cumulative amount of information entropy reduction when each node splits in the decision tree generated in the random forest model with the cumulative threshold, and when the cumulative amount of information entropy reduction when a node splits is greater than the cumulative threshold, the node is an important factor. There must be at least two important factors, and the factor that can be improved through ecological restoration is selected as the key factor.

[0030] Furthermore, the variation gradient of each key factor along its connected path is calculated using the following formula:

[0031] ;

[0032] In the above formula, This represents the gradient of variation along the connected path containing the m-th key factor. This represents the average functional value of the m-th key factor in the ecological protection zone. This represents the average functional value of the m-th key factor in the ecological restoration area. This represents the length of the connected path containing the m-th key factor; m ranges from 1 to M, where M represents the number of key factors.

[0033] Furthermore, ecosystem functions include, but are not limited to, water production, carbon storage, food production, and soil conservation; influencing factors include meteorological, topographical, vegetation, soil, and anthropogenic engineering factors.

[0034] Furthermore, S5 includes the following steps:

[0035] S51. For ecological protection zones, carry out in-situ conservation;

[0036] S52. Carry out ecological restoration work in ecological restoration areas;

[0037] S53. Add up the variation gradients of all edges connected to each ecological restoration zone to obtain the cumulative variation value of the ecological restoration zone. Sort all ecological restoration zones by their cumulative variation values ​​from largest to smallest. The higher the cumulative variation value, the higher the restoration priority of the corresponding ecological restoration zone. Perform the corresponding restoration work according to the priority of the ecological restoration zone.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] This invention lays the foundation for synergistic effects among multiple ecosystem functions by pre-judging the functional relationships of ecosystems, avoiding the neglect of trade-offs between these functions. By quantifying the synergistic potential of multiple ecosystem functions, it effectively distinguishes key areas for ecological protection and restoration work. Specifically, it focuses on ecological protection work in areas with low synergistic potential (where multiple ecosystem functions are synergistic and already at a high level of development), and on ecological restoration work in areas with high synergistic potential (where multiple ecosystem functions are synergistic but at a relatively low level of development). This avoids the problem of traditional ecological network construction techniques that only focus on areas with high levels of ecosystem function development. By using the connectivity paths of key factors affecting synergistic potential as edges of the ecological network and defining the variation gradient of key factors on these paths as edge attributes, it provides a quantitative technique for selecting key areas and key restoration factors for ecological restoration work aimed at synergistic effects among multiple ecosystem functions. Attached Figure Description

[0040] Figure 1 This is a flowchart of the ecological network construction method of the present invention.

[0041] Figure 2 This is a schematic diagram of the ecological network constructed in this invention. Detailed Implementation

[0042] The technical solution of the present invention will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are not all embodiments of the present invention. All other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0043] like Figure 1 As shown, this invention provides a method for constructing an ecological network that promotes multifunctional synergy and efficiency in ecosystems, comprising the following steps:

[0044] S1. Divide the ecosystem region into multiple grid cells, calculate the functional values ​​of each type within each grid cell, and sort all grid cell functional values ​​from largest to smallest within each functional type to obtain the functional value ranking value of each grid cell. This yields the correlation coefficient between any two ecosystem functions. Based on the correlation coefficient, determine the relationship between these two ecosystem functions, including synergistic and trade-off relationships. The specific steps include:

[0045] S11. Ecosystem functions include water production, carbon storage, food production, and soil conservation. The function value of each ecosystem function is calculated using the following formula.

[0046] The water production function value of the j-th grid cell is calculated using the following formula:

[0047] ;

[0048] In the above formula, This represents the water production function value of the j-th grid cell. This represents the potential evapotranspiration of the j-th grid cell. This represents the precipitation in the j-th grid cell. Dimensionless parameters that characterize the surface features of a region.

[0049] The carbon storage function value of the j-th grid cell is calculated using the following formula:

[0050] ;

[0051] In the above formula, This represents the carbon storage function value of the j-th grid cell. , , , These represent the aboveground biomass (surviving vegetation above the ground), underground biomass (generally referring to the living root system of plants), litter (including fallen leaves, dead standing trees, and dead fallen trees) and soil carbon storage of land use type t in the j-th grid cell, respectively.

[0052] The grain production function value of the j-th grid cell is calculated using the following formula:

[0053] ;

[0054] In the above formula, This represents the grain production function value of the j-th grid cell. This represents the normalized vegetation index of the j-th raster cell. This represents the sum of the normalized vegetation indices of all raster cells representing the land use type of the region, specifically for crops. This indicates the regional grain output obtained from statistical yearbooks.

[0055] The soil conservation function value of the j-th grid cell is calculated using the following formula:

[0056] ;

[0057] In the above formula, This represents the soil retention function value of the j-th raster cell. The rainfall erosion factor is calculated based on rainfall intensity and rainfall kinetic energy; K represents the soil erodibility factor, which depends on the content of silt, clay, sand, and organic carbon in the soil. represents the slope length and slope factor, calculated based on the terrain; C represents the vegetation management factor, which is a dimensionless factor; P represents the engineering measures factor, which is a dimensionless factor.

[0058] S12. Calculate the correlation coefficient between each pair of ecosystem functions based on the functional value ranking of each grid cell corresponding to each ecosystem function. When the correlation coefficient is greater than 0, it indicates that the two ecosystem functions are synergistic. When the correlation coefficient is less than 0, it indicates that the two ecosystem functions are trade-offs.

[0059] Specifically, the correlation coefficient between the functions of the two ecosystems is calculated using the following formula:

[0060] ;

[0061] In the above formula, Let represent the correlation coefficient between the i-th ecosystem function and the l-th ecosystem function, where i and l both take values ​​from 1 to N, and N represents the total number of ecosystem functions. This represents the ranking value of the j-th raster cell in the i-th ecosystem function. This represents the average of the sorted function values ​​of all raster cells for the i-th type of ecosystem function. This represents the ranking value of the j-th raster cell in the l-th ecosystem function. represents the average of the sorted function values ​​of all raster cells for the l-th type of ecosystem function, and n represents the total number of raster cells.

[0062] S2. Select ecosystem functions exhibiting synergistic relationships, calculate the comprehensive development index and the potential value of synergistic enhancement of ecosystem multifunctionality for each grid cell, and delineate ecological protection zones and ecological restoration zones based on the potential value of synergistic enhancement of ecosystem multifunctionality, specifically as follows:

[0063] The comprehensive development index of the j-th grid cell is calculated using the following formula:

[0064] ;

[0065] In the above formula, This represents the comprehensive development index of the j-th grid cell. Y represents the weight of the y-th ecosystem function exhibiting a synergistic relationship, and Y represents the total number of selected ecosystem functions exhibiting a synergistic relationship. Take 1, The standardized value of the function of the y-th ecosystem function that exhibits a synergistic relationship is represented.

[0066] The potential value of multifunctional synergistic effects in an ecosystem is calculated using the following formula:

[0067] ;

[0068] In the above formula, This represents the potential value for multifunctional synergistic effects of the ecosystem in the j-th grid cell.

[0069] Based on the potential for synergistic effects across multiple ecosystem functions, determine whether each grid cell belongs to an ecological protection zone or an ecological restoration zone; when At that time, the grid unit is an area with high potential for synergistic effects and is an ecological restoration unit. At that time, the grid unit is an area with low potential for synergistic effect and is an ecological protection unit; adjacent ecological restoration units are formed into ecological restoration areas, and multiple adjacent ecological protection units are formed into ecological protection areas.

[0070] S3. Using all the influencing factors corresponding to all ecosystem functions in each grid cell as independent variables and the corresponding potential value of synergistic enhancement of ecosystem functions as dependent variables, construct a random forest model. The influencing factors include five categories: meteorological, topographic, vegetation, soil, and anthropogenic factors. Meteorological factors include precipitation, temperature, radiation, wind speed, and humidity; topographic factors include altitude and slope; vegetation factors include vegetation coverage, leaf area index, and vegetation type; soil factors include soil water content, soil particle size, soil organic carbon, soil bulk density, and porosity; and anthropogenic factors include GDP, population density, impermeable ground area, terrace area, silt-retaining dam area, and reservoir area.

[0071] Set a cumulative threshold. Compare the cumulative amount of information entropy reduction when each node splits in the decision tree generated in the random forest model with the cumulative threshold. When the cumulative amount of information entropy reduction when a node splits is greater than the cumulative threshold, the node is considered an important factor. There must be at least two important factors. Among the important factors, those that can be improved through ecological restoration are selected as key factors. Only meteorological factors cannot be improved through ecological restoration.

[0072] S4. Using the center points of the ecological protection zones and ecological restoration zones identified in step S2 as two types of nodes, the shortest connecting paths between adjacent nodes of these two types are designated as edges. Only nodes of different types are connected. The variation gradient of key factors along their respective connecting paths is defined as an attribute of that edge, thus constructing an ecological network. Figure 2 As shown, Figure 2 The thicker the edge in the diagram, the better the ecological restoration effect.

[0073] The variation gradient along the connected path containing each key factor is calculated using the following formula:

[0074] ;

[0075] In the above formula, This represents the gradient of variation along the connected path containing the m-th key factor. This represents the average functional value of the m-th key factor in the ecological protection zone. This represents the average functional value of the m-th key factor in the ecological restoration area. This represents the length of the connected path containing the m-th key factor; m ranges from 1 to M, where M represents the number of key factors.

[0076] S5. Based on the ecological network constructed in step S4, multifunctional protection and restoration work is carried out; specifically:

[0077] S51. For ecological protection areas, because their ecosystems have a high degree of multifunctional development and little potential for synergistic effects, in-situ conservation should be carried out.

[0078] S52. For ecological restoration areas, because their ecosystems have a low level of multifunctional integrated development and great potential for synergistic effects, they are suitable for carrying out ecological restoration work.

[0079] S53. Add up the variation gradients of all edges connected to each ecological restoration zone to obtain the cumulative variation value of the ecological restoration zone. Sort all ecological restoration zones by their cumulative variation values ​​from largest to smallest. The higher the cumulative variation value, the higher the restoration priority of the corresponding ecological restoration zone. Perform the corresponding restoration work according to the priority of the ecological restoration zone.

[0080] This invention lays the foundation for synergistic effects among multiple ecosystem functions by pre-judging the functional relationships of ecosystems, avoiding the neglect of trade-offs between these functions. By quantifying the synergistic potential of multiple ecosystem functions, it effectively distinguishes key areas for ecological protection and restoration work. Specifically, it focuses on ecological protection work in areas with low synergistic potential (where multiple ecosystem functions are synergistic and already at a high level of development), and on ecological restoration work in areas with high synergistic potential (where multiple ecosystem functions are synergistic but at a relatively low level of development). This avoids the problem of traditional ecological network construction techniques that only focus on areas with high levels of ecosystem function development. By using the connectivity paths of key factors affecting synergistic potential as edges of the ecological network and defining the variation gradient of key factors on these paths as edge attributes, it provides a quantitative technique for selecting key areas and key restoration factors for ecological restoration work aimed at synergistic effects among multiple ecosystem functions.

[0081] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A method for constructing an ecological network oriented towards multifunctional synergistic enhancement of ecosystems, characterized in that, Includes the following steps: S1. Divide the ecosystem region into multiple grid units, set multiple types of ecosystem functions, obtain the correlation coefficient of any two types of ecosystem functions, and determine the relationship between the two ecosystem functions, including synergistic and trade-off relationships. S2. Select ecosystem functions exhibiting synergistic relationships, calculate the synergistic potential value of ecosystem multi-functionality in each grid cell, and delineate ecological protection zones and ecological restoration zones based on the synergistic potential value of ecosystem multi-functionality. The synergistic potential value of ecosystem multi-functionality is calculated using the following formula: In the above formula, This represents the potential value for multifunctional synergistic effects of the ecosystem in the j-th grid cell. This represents the comprehensive development index of the j-th grid cell; Based on the potential for synergistic effects across multiple ecosystem functions, ecological protection zones and ecological restoration zones are delineated. The specific method is as follows: When… At that time, the grid unit represents an area with low potential for synergistic effects and is designated as an ecological protection unit; when At that time, the grid unit is an area with high potential for synergistic effect and is an ecological restoration unit; adjacent ecological restoration units are formed into ecological restoration areas, and multiple adjacent ecological protection units are formed into ecological protection areas; S3. Each ecosystem function includes multiple influencing factors. All influencing factors of each grid cell are used as independent variables, and the corresponding potential value of synergistic enhancement of ecosystem functions is used as the dependent variable. A random forest model is constructed. Based on the random forest model, key factors are screened from the influencing factors. The screening method for key factors is as follows: a cumulative threshold is set, and the cumulative amount of information entropy reduction when each node splits in the decision tree generated in the random forest model is compared with the cumulative threshold. When the cumulative amount of information entropy reduction when a node splits is greater than the cumulative threshold, the node is an important factor. There are at least two important factors. Among the important factors, the factors that can be improved through ecological restoration are selected as key factors. S4. Take the center point of the ecological protection zone and the center point of the ecological restoration zone divided in step S2 as two types of nodes, take the shortest connecting path between two adjacent types of nodes as the edge, and define the variation gradient of the key factor on the connecting path as the attribute of the edge, thereby constructing an ecological network. S5. Based on the ecological network constructed in step S4, multifunctional protection and repair work is carried out.

2. The method for constructing an ecological network for multifunctional synergistic enhancement of an ecosystem according to claim 1, characterized in that, S1 specifically includes the following steps: S11. Calculate the functional value of each ecosystem function; S12. In each type of ecosystem function, sort all grid cell function values ​​from largest to smallest to obtain the sorted function value of each grid cell, and then calculate the correlation coefficient between each pair of ecosystem functions. When the correlation coefficient is greater than 0, it indicates that the two ecosystem functions are synergistic; when the correlation coefficient is less than 0, it indicates that the two ecosystem functions are trade-offs.

3. The method for constructing an ecological network for multifunctional synergistic enhancement of an ecosystem according to claim 2, characterized in that, The correlation coefficient in step S12 is calculated using the following formula: In the above formula, Let represent the correlation coefficient between the i-th ecosystem function and the l-th ecosystem function, where i and l both take values ​​from 1 to N, and N represents the total number of ecosystem functions. This represents the ranking value of the j-th raster cell in the i-th ecosystem function. This represents the average of the sorted function values ​​of all raster cells for the i-th type of ecosystem function. This represents the ranking value of the j-th raster cell in the l-th ecosystem function. represents the average of the sorted function values ​​of all raster cells for the l-th type of ecosystem function, and n represents the total number of raster cells.

4. The method for constructing an ecological network for multifunctional synergistic enhancement of an ecosystem according to claim 1, characterized in that, The comprehensive development index of the j-th grid cell is calculated using the following formula: In the above formula, Y represents the weight of the y-th ecosystem function exhibiting a synergistic relationship, and Y represents the total number of selected ecosystem functions exhibiting a synergistic relationship. Take 1, The standardized value of the function of the y-th ecosystem function that exhibits a synergistic relationship is represented.

5. The method for constructing an ecological network for multifunctional synergistic enhancement of an ecosystem according to claim 4, characterized in that, The variation gradient of each key factor along its connected path is calculated using the following formula: In the above formula, This represents the gradient of variation along the connected path containing the m-th key factor. This represents the average functional value of the m-th key factor in the ecological protection zone. This represents the average functional value of the m-th key factor in the ecological restoration area. This represents the length of the connected path containing the m-th key factor; m ranges from 1 to M, where M represents the number of key factors.

6. The method for constructing an ecological network for multifunctional synergistic enhancement of an ecosystem according to claim 1, characterized in that, Ecosystem functions include water production, carbon storage, food production, and soil conservation; influencing factors include meteorological, topographical, vegetation, soil, and anthropogenic engineering factors.

7. The method for constructing an ecological network for multifunctional synergistic enhancement of an ecosystem according to claim 1, characterized in that, S5 includes the following steps: S51. For ecological protection zones, carry out in-situ conservation; S52. Carry out ecological restoration work in the ecological restoration area; S53. Add up the variation gradients of all edges connected to each ecological restoration zone to obtain the cumulative variation value of the ecological restoration zone. Sort all ecological restoration zones by their cumulative variation values ​​from largest to smallest. The higher the cumulative variation value, the higher the restoration priority of the corresponding ecological restoration zone. Perform the corresponding restoration work according to the priority of the ecological restoration zone.

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