Diversity description method for multilayer vertical space structure of wetland vegetation

Abstract

The invention provides a multi-layer vertical space structure diversity description method for wetland vegetation, which belongs to the field of ecology and comprises the following steps: dividing the wetland vegetation into a canopy layer, a middle layer and a bottom layer by height; collecting parameters of vegetation in different hierarchies to construct corresponding models to describe the structural diversity of each hierarchie. According to the method, the structural diversity of the bottom layer, the middle layer and the canopy layer of the wetland vegetation and the arbor vegetation and the herbaceous vegetation of the wetland can be described at the full-level multi-angle vertical height, comprehensive multi-aspect and multi-dimensional evaluation of the vegetation structural diversity is realized, and the structural characteristics of the wetland vegetation can be reflected more comprehensively and accurately.

Description

Technical Field

[0001] The present invention belongs to the field of ecology, and particularly relates to a method for describing the diversity of the multi-layer vertical spatial structure of wetland vegetation. Background Art

[0002] The function intensity of an ecosystem is not only related to the scale, vegetation, and type of the ecosystem, but also has a certain relationship with the vegetation distribution within the ecosystem. The individual sizes and physical arrangements of various species within the ecosystem have different effects on the function of the ecosystem by affecting the flow and utilization of energy and resources such as heat and nutrients, especially the vegetation in the ecosystem. Therefore, accurately quantifying and describing the vegetation structure diversity and mastering the current situation and changes of the vegetation structure diversity are very important for the study of the ecosystem function.

[0003] At present, there have been many research and calculation methods for diversity research and quantification research at various levels, such as α, β, γ diversity, distribution pattern index, segregation index, etc. However, they focus on describing the abundance and number of communities, or the horizontal spatial distribution of forest stands from a single angle, and these indices cannot directly visualize the three-dimensional structural form of forest stands. Moreover, for wetland vegetation, the distribution of aerial roots and herbaceous vegetation together constitute a complex lower layer of the forest stand. For mangrove wetlands with high ecosystem productivity and complex forest stand structures, specific structural diversity description and quantitative calculation methods need to be established. Summary of the Invention

[0004] The purpose of the present invention is to describe the structural diversity of wetland habitat vegetation from three vertical levels, namely the bottom layer, the middle layer, and the canopy layer, based on individual vegetation, aiming at the complex root systems and stem and leaf structures of wetland vegetation, and calculate the structural diversity indices of each level.

[0005] The technical solution of the present invention is as follows: A method for describing the diversity of the multi-layer vertical spatial structure of wetland vegetation, comprising the following steps: Dividing wetland vegetation into a canopy layer, a middle layer, and a bottom layer by height; Collecting the parameters of the vegetation in different layers to construct corresponding models to describe the structural diversity of each layer.

[0006] Further, it is characterized in that collecting the parameters of the vegetation in different layers to construct corresponding models to describe the structural diversity of each layer specifically is: Collecting the position and tree height data of mangrove trees in the wetland to construct a three-dimensional fold model of tree height, and obtaining the tree height structural diversity of the wetland vegetation canopy layer based on the three-dimensional fold model of tree height; Collecting the basal diameter and breast diameter data of the vegetation in the wetland plot to construct a three-dimensional main stem frustum model, and obtaining the main stem structural diversity of the wetland vegetation middle layer based on the three-dimensional main stem frustum model; Collect data on the height of aerial roots above the ground and the distance from the main trunk of mangrove plants in wetland plots to construct a three-dimensional radial root model, and obtain the diversity of above-ground root structures of wetland vegetation based on the three-dimensional radial root model; Collect data on the height and distribution boundary positions of herbaceous plants in wetland plots to construct a three-dimensional model of herbaceous plants, and obtain the three-dimensional diversity of the herbaceous layer of wetland vegetation based on the three-dimensional model of herbaceous plants; Obtain the diversity of the bottom layer structure of wetland vegetation based on the diversity of the above-ground root structure of wetland vegetation and the diversity of the herbaceous layer structure of wetland vegetation.

[0007] Furthermore, collect data on the position and tree height of mangrove trees in the wetland to construct a three-dimensional wrinkled tree height model, and the specific method for obtaining the diversity of the tree height structure of the canopy layer of wetland vegetation based on the three-dimensional wrinkled tree height model is as follows: Take the abscissa of the tree position in the plot as x, the ordinate as y, and the height of the tree crown vertex as z to construct a triangular mesh diagram; Calculate the tree height diversity index of the three-dimensional wrinkled tree height model according to the areas of the triangles in the triangular mesh diagram. The formula is: , In the formula, is the area of any triangular grid in the triangular mesh diagram, A is the area of the wetland plot, n is the total number of triangles in the grid, and l is the l-th triangle.

[0008] Furthermore, collect data on the base diameter and breast diameter of vegetation in wetland plots to construct a three-dimensional main stem frustum model, and the specific method for obtaining the diversity of the main stem structure in the middle layer of wetland vegetation based on the three-dimensional main stem frustum model is as follows: Take the abscissa of the tree position in the plot as x and the ordinate as y, and draw a distribution diagram of the stem thickness of the main stem of the vegetation according to the data on the base diameter and breast diameter of the vegetation; Calculate the diversity index of the main stem structure in the middle layer of the trees at any height in the plot based on the distribution diagram of the stem thickness of the main stem of the vegetation for the three-dimensional main stem frustum model. The formula is: , In the formula, S R is the cross-sectional area at any base diameter of the vegetation in the grid, S r is the cross-sectional area at any crown base height of the vegetation in the grid, A is the area of the wetland plot, m is the total number of frustum cross-sections in the plot, and j is the j-th frustum cross-section.

[0009] Furthermore, collect data on the height of aerial roots above the ground and the distance from the main trunk of mangrove plants in wetland plots to construct a three-dimensional radial root model, and the specific method for obtaining the diversity of the above-ground root structure of wetland vegetation based on the three-dimensional radial root model is as follows: Taking the abscissa of the tree position in the sample plot as x, the ordinate as y, the height of the aerial roots as z, the distribution radius of the aerial roots as r, and the arc length of the aerial root fan as l, draw a radial network diagram of the vegetation roots; Based on the radial network diagram of the vegetation roots, calculate the three-dimensional radial model of the roots to obtain the three-dimensional structural diversity index of the roots. The formula is: , In the formula, is the area of any sector grid in the radial network diagram of the vegetation roots, A is the area of the wetland sample plot, p is the total number of sectors in the grid, and k is the kth sector.

[0010] Furthermore, collect the height and distribution boundary position data of the herbaceous plants in the wetland sample plot to construct a three-dimensional model of the herbaceous plants. The three-dimensional diversity of the herbaceous layer of the wetland vegetation obtained based on the three-dimensional model of the herbaceous plants is specifically: Taking the x and y of the distribution edge position of the herbaceous plants in each area of the sample plot and the height h of the herbaceous vegetation, draw a three-dimensional distribution structure diagram of the vegetation; Based on the three-dimensional distribution structure diagram of the vegetation, calculate the three-dimensional model of the herbaceous plants to obtain the three-dimensional diversity index of the herbaceous layer. The formula is: , In the formula, is the area of any triangular grid in each top surface grid in the three-dimensional distribution structure diagram, A is the area of the wetland sample plot, is the height of each vegetation, is the height of the tallest herbaceous vegetation in the sample plot, is the order after sorting the herbaceous plants from small to large in height, and n is the total number of herbaceous plant individuals.

[0011] Furthermore, the bottom layer structural diversity of the wetland vegetation obtained based on the above-ground root structural diversity of the wetland vegetation and the herbaceous layer structural diversity of the wetland vegetation is specifically: , Among them, is the three-dimensional structural diversity index of the roots, is the three-dimensional diversity index of the herbaceous layer.

[0012] Compared with the prior art, the present invention has the following advantages: The present invention establishes a method for describing the diversity at the vegetation structure level, which can describe the structural diversity at all levels and multiple angles of the bottom layer, middle layer and canopy of the wetland vegetation, as well as the wetland tree vegetation and herbaceous vegetation, in the vertical height, realizes the comprehensive evaluation of the vegetation structure diversity in multiple aspects and dimensions, and can more comprehensively and accurately reflect the structural characteristics of the wetland vegetation.

[0013] The present invention comprehensively considers the influence of the size distribution and physical arrangement of the roots, stems, and leaves of wetland vegetation on the overall habitat vegetation structure. The adventitious roots growing at the bottom layer in wetland vegetation are the main characteristics that distinguish it from other vegetation types. This method takes the structural diversity of various types of adventitious roots as an important part and comprehensively considers the structural diversity of wetland vegetation. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The drawings generally illustrate various embodiments by way of example and not limitation, and are used together with the description of the specification and the claims to illustrate the embodiments of the invention. When appropriate, the same reference numerals are used throughout the drawings to refer to the same or similar parts. Such embodiments are illustrative and are not intended to be an exhaustive or exclusive embodiment of the device or method.

[0015] Figure 1 It shows a schematic flow diagram of the method of the present invention; Figure 2 It shows a schematic diagram of the triangular network diagram of the tree canopy top height of the present invention; Figure 3 It shows a schematic diagram of any triangle ΔABC in the triangular grid of the present invention; Figure 4 It shows a schematic diagram of the three-dimensional main stem frustum model of the tree of the present invention; Figure 5 It shows a schematic diagram of the relevant calculation of the stem diameter distribution at the plant height H drawn based on the three-dimensional main stem frustum model of the present invention; Figure 6 It shows a schematic diagram of the radiation network diagram of the vegetation root system of the present invention; Figure 7 It shows a schematic diagram of the three-dimensional distribution structure diagram of wetland herbaceous vegetation of the present invention; Figure 8 It shows a schematic diagram of the vertical three-dimensional structure of the canopy density of herbaceous vegetation of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0017] As Figure 1 shown, the present invention discloses a method for describing the multi-layer vertical spatial structure diversity of wetland vegetation, including the following steps: S1 Collect the position and tree height data of the wetland sample plot vegetation (tall mangrove trees), establish a three-dimensional fold model of the tree height according to the formula, determine the form of the three-dimensional fold layer of the tree height, calculate the tree height structure diversity, and describe the tree height structure diversity of the wetland vegetation canopy; S2 Collect the data of the base diameter and breast diameter of the wetland plot vegetation, establish a three-dimensional frustum model of the main stem according to the formula, determine the three-dimensional shape of the stem, calculate the structural diversity of the main stem, and describe the structural diversity of the main stem in the middle layer of the wetland vegetation; S3 Collect the data of the height of the aerial roots above the ground and the distance from the main trunk of the wetland plot vegetation (mangrove plants), establish a three-dimensional radial model of the root system according to the formula, determine the three-dimensional radial shape of the root system, calculate the structural diversity of the root system, and describe the structural diversity of the aerial roots of the wetland vegetation; S4 For herb modeling, collect the height of the herbs in the wetland plot (mainly Acanthus ilicifolius) and the data of the distribution boundary positions of the herbaceous plants in the plot, establish a three-dimensional model of the herbaceous plants according to the formula, determine the three-dimensional shape of the herbaceous plants, calculate the structural diversity of the herbaceous plants, and describe the structural diversity of the herbaceous layer of the wetland vegetation.

[0018] S5 Based on the structural diversity of the aerial roots and the structural diversity of the herbaceous layer of the vegetation, determine the structural diversity of the bottom layer of the wetland vegetation.

[0019] Refer to Figure 2 , connect the top of the canopy of any tree in the quadrat with the tops of the canopies of the two nearest adjacent trees to form a triangle. Connect the tops of the canopies of all the trees in the quadrat in this way to form a three-dimensional folded triangular network, which constitutes the triangular network of the tree canopy top height. Refer to Figure 3 , according to the definition of the cross product of two vectors, the area of this triangle can be calculated: .

[0020] Based on the collected data of the positions and heights of the mangrove arbor vegetation in the wetland, construct a three-dimensional model of the tree height according to the canopy top height in the quadrat. Take the abscissa of the tree position in the plot as x, the ordinate as y, and the height of the canopy vertex as z, and draw the triangular network diagram of each quadrat according to the quadrat data. The three-dimensional folding index FS,I of the tree canopy crown top height is calculated by the formula: , In the formula, is the area of any triangular grid in the triangular network diagram, A is the area of the wetland plot, n is the total number of triangles in the grid, and l is the l-th triangle.

[0021] According to the areas of the triangles in the triangular network in the quadrat, the three-dimensional folding index of the tree canopy top height of the quadrat can be calculated. The three-dimensional folding index of the tree canopy top height of the quadrat is the tree height diversity index of the quadrat. The higher the tree height diversity index, the more complex the vegetation height structure in the quadrat.

[0022] Below the tree canopy is the main stem of the tree. Since most of the branches of the tree stem are concentrated in the upper and middle parts, and there is an overlapping part between the branch stem and the canopy after branching, only the main stem part below the branch stem is considered for modeling and simulation. Based on the collected tree position data and basal diameter and breast diameter data of wetland quadrats, a three-dimensional frustum model of the main stem of vegetation is constructed. The radius of the tree trunk gradually shrinks from the bottom to the top. The main stem of the tree can be approximately understood as a frustum with the basal diameter as the circumference of the bottom surface of the cone and the height of the crown base as the height. Refer to Figure 4 。

[0023] Taking the abscissa of the tree position in the plot as x and the ordinate as y, draw the stem diameter distribution map of the main stem of the vegetation at any height in each quadrat according to the quadrat data. Taking Figure 5 the frustum shown as an example, the calculation formulas for the stem diameter DR and cross-sectional area S at the plant height H are: , where R is the basal diameter of the tree, H is any height on the main stem of the tree, r1.3 is the radius at the breast diameter (1.3m) of the tree, and R is the radius at the basal diameter of the tree.

[0024] The structural diversity index F of the middle layer of the main stem of the tree at any height in the plot S，2 is calculated by the formula: , where S R is the cross-sectional area at the basal diameter of any vegetation in the grid, S r is the cross-sectional area at the crown base height of any vegetation in the grid, A is the area of the wetland quadrat, m is the total number of frustum cross-sections in the quadrat, and j is the jth frustum cross-section.

[0025] The lower layer of wetland vegetation mainly consists of various plant roots and herbaceous plants. The method of the present invention is calculated in two parts respectively. The biggest difference between wetland vegetation and the vegetation of other ecosystems is the widely growing multi-type aerial roots, bamboo shoot-like roots, knee-like roots, plank roots, etc., which have a certain height and are radially distributed in a fan shape with the tree position as the midpoint. Based on the collected data of the height of aerial roots above the ground and the distance from the main trunk of the wetland quadrat vegetation (mangrove plants), a three-dimensional radiation model of the root system is established. Taking the abscissa of the tree position in the plot as x, the ordinate as y, the height of the aerial root as z, the distribution radius of the aerial root as r, and the arc length of the fan-shaped aerial root as l, draw the root system radiation network diagram of the vegetation in each quadrat, as Figure 6 shown. The calculation formula for the three-dimensional structural diversity index F of the root system is: , where is the area of any fan-shaped grid in the root system radiation network diagram of the vegetation, A is the area of the wetland quadrat, p is the total number of fans in the grid, and k is the kth fan.

[0026] Such as Figure 6, For any sector in the fan-shaped grid, given the distribution radius \(r\) and arc length \(l\) of the aerial roots, the area of the sector can be calculated. Since the heights of the fan-shaped grids are different, there may be overlapping parts. The areas of the overlapping parts are calculated separately for each fan-shaped grid: , Based on the areas of the sectors in the fan-shaped network within the quadrat, the root system structure diversity index of the quadrat can be calculated.

[0027] The herbaceous vegetation in the mangrove forest is mainly Acanthus ilicifolius. In some areas, Acanthus ilicifolius grows vigorously, with a height exceeding 1 meter and having intersections with the main stem and roots. Based on the herb height and distribution boundary data of the wetland quadrats, a three-dimensional model of wetland herbaceous plants is constructed. The wetland herbaceous plants are distributed in patches. The vegetation at the edges of the distribution patches is relatively low, while in the middle it is relatively high. The entire patch forms a three-dimensional spatial structure with an irregular triangular grid on the top surface and the herbaceous plant distribution area as the bottom. The top surface is similar to the three-dimensional fold model of the tree height. The height of the herbaceous vegetation can be obtained by combining Lidar laser radar scanning and field measurement. Using the edge positions \((x, y)\) of the herbaceous plant distribution in each patch of the quadrat and the height \(h\) of the herbaceous vegetation in each patch, a three-dimensional distribution structure diagram of the herbaceous vegetation within each quadrat is drawn, as Figure 7 .

[0028] Three vertical spaces are divided according to the height of the herbaceous plants in the quadrat. For example, if the maximum height of the herbaceous plants is 1.5 m, then three layers of 0 cm - 50 cm, 50 cm - 100 cm, and 100 cm - 150 cm are set. The leaf area index meter is used to operate at the top of the canopy and the bottom of each layer respectively to measure the leaf area index at the top and the bottom of each layer, obtain the non-intercepted scattering amount of each vertical layer of the canopy, and the light transmittance of each layer of the canopy can be obtained according to the formula: , In the formula, is the zenith angle, \(L\) is the leaf area index of this layer, is the light transmittance at a certain zenith angle.

[0029] For the top layer of the canopy, the light transmittance can be directly calculated through the leaf area index. For the canopy layers below the first layer, the light transmittance can be calculated through the formula: , In the formula, \(T\) up is the light transmittance of all upper layers of a certain vertical canopy, and \(T\) un is the light transmittance of the lower layer of a certain vertical canopy.

[0030] In this way, the density of each layer of the herbaceous vegetation canopy is determined. Combining with the three-dimensional fold model of the herbaceous vegetation, a vertical three-dimensional structure of the herbaceous vegetation canopy density is established, as Figure 8 shown.

[0031] The three-dimensional complexity of herbaceous vegetation consists of two aspects: the degree of grid wrinkles on the top surface and the degree of height difference. Therefore, the three-dimensional diversity index consists of two parts. The height difference of herbaceous vegetation in the plot is characterized by the Gini index of the herbaceous vegetation height. The calculation formula of the three-dimensional diversity index F of herbaceous vegetation is as follows: , In the formula, Si is the area of any triangular grid in each top surface grid, A is the area of the plot, hi is the height of each vegetation, h is the height of the tallest herbaceous vegetation in the plot, i is the order after sorting the herbaceous plants from small to large in height, and n is the total number of herbaceous plant individuals.

[0032] The calculation method of the three-dimensional fold index of the triangular grid on the herbaceous top surface is the same as that of the three-dimensional fold index of the tree height.

[0033] According to the height of herbaceous plants (mainly Acanthus ilicifolius) in the wetland plot and the data of the distribution boundary position of herbaceous plants in the plot, the structural diversity index of herbaceous plants is calculated.

[0034] The bottom layer structure of the vegetation is mainly composed of the aerial roots of the vegetation and herbaceous plants. Therefore, the bottom layer structure diversity index of the vegetation is composed of two parts based on the above-ground root structure diversity and the herbaceous layer structure diversity of the vegetation, so as to determine the bottom layer structure diversity of the wetland vegetation.

[0035] , Among them, is the three-dimensional structure diversity index of the root system, is the three-dimensional diversity index of the herbaceous layer. As described above, it is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A method for describing the diversity of multi-layer vertical spatial structure of wetland vegetation, characterized in that: The following steps are involved: Wetland vegetation is divided into canopy, middle layer and bottom layer by height; The parameters of vegetation at different levels are collected to construct corresponding models to describe the structural diversity of each level.

2. The method for describing the diversity of multi-layer vertical spatial structure of wetland vegetation according to claim 1, characterized in that: The parameters of vegetation at different levels are collected to construct corresponding models to describe the structural diversity of each level: The location and tree height data of mangrove trees in the wetland are collected to construct a three-dimensional fold model of tree height, and the tree height structure diversity of wetland vegetation canopy is obtained based on the three-dimensional fold model of tree height; The base diameter and breast diameter of vegetation in the wetland sample plot are collected to construct a three-dimensional main stem frustum model, and the structural diversity of the middle-layer main stems of the wetland vegetation is obtained based on the three-dimensional main stem frustum model; The height of aerial roots of mangrove plants above the ground and their distance from the main trunk in the wetland sample plots were collected to construct a three-dimensional radiation model of the root system, and the diversity of the above-ground root system structure of wetland vegetation was obtained based on the three-dimensional radiation model of the root system; Collecting the height and distribution boundary position data of herbaceous plants in the wetland sample plot to construct a three-dimensional model of herbaceous plants, and obtaining the three-dimensional diversity of the herbaceous layer of wetland vegetation based on the three-dimensional model of herbaceous plants; The diversity of the bottom layer structure of wetland vegetation is obtained based on the diversity of the above-ground root structure of wetland vegetation and the diversity of the herb layer structure of wetland vegetation.

3. The method for describing the diversity of multi-layer vertical spatial structure of wetland vegetation according to claim 2, characterized in that: The location and tree height data of mangrove trees in the wetland are collected to construct a three-dimensional tree height fold model, and the tree height structure diversity of wetland vegetation canopy is obtained based on the three-dimensional tree height fold model: The triangulated network map is constructed with the tree position in the plot as x, the ordinate as y, and the height of the crown vertex as z; The tree height diversity index is obtained by calculating the three-dimensional fold model of tree height according to the area of ​​each triangle in the triangulated network diagram. The formula is: ， In the formula, is the area of ​​any triangular mesh in the triangulated network diagram, A is the area of ​​the wetland plot, n is the total number of triangles in the mesh, and l is the lth triangle.

4. The method for describing the diversity of multi-layer vertical spatial structure of wetland vegetation according to claim 2, characterized in that: The base diameter and breast diameter data of vegetation in the wetland sample plot were collected to construct a three-dimensional main stem frustum model. Based on the three-dimensional main stem frustum model, the structural diversity of the middle-layer main stems of wetland vegetation was obtained as follows: With the tree position in the plot as x and the ordinate as y, the main stem diameter distribution map of vegetation was drawn based on the vegetation base diameter and breast diameter data; Based on the main stem distribution map of the vegetation, the three-dimensional main stem frustum model is calculated to obtain the structural diversity index of the middle-level main stems of trees at any height in the sample plot, and the formula is: ， In the formula, S R is the cross-sectional area at the base diameter of any vegetation in the grid, S r is the cross-sectional area at the height of any vegetation crown in the grid, A is the area of ​​the wetland plot, m is the total number of frustum sections in the plot, and j is the jth frustum section.

5. The method for describing the diversity of multi-layer vertical spatial structure of wetland vegetation according to claim 2, characterized in that: The height of aerial roots of mangrove plants above the ground and their distance from the trunk in the wetland sample plot were collected to construct a three-dimensional root radiation model. Based on the three-dimensional root radiation model, the structural diversity of the above-ground root systems of wetland vegetation was obtained as follows: With the tree position in the plot as x, the ordinate as y, the aerial root height as z, the aerial root distribution radius as r, and the aerial root fan arc length as l, a vegetation root radial network diagram was drawn; Based on the vegetation root radiation network diagram, the root three-dimensional radiation model is calculated to obtain the root three-dimensional structural diversity index, and the formula is: ， In the formula, is the area of ​​any sector grid in the vegetation root radiation network diagram, A is the area of ​​the wetland plot, p is the total number of sectors in the grid, and k is the kth sector.

6. The method for describing the diversity of multi-layer vertical spatial structure of wetland vegetation according to claim 2, characterized in that: The height and distribution boundary position data of herbaceous plants in the wetland sample plot were collected to construct a three-dimensional model of herbaceous plants. Based on the three-dimensional model of herbaceous plants, the three-dimensional diversity of the herbaceous layer of wetland vegetation was obtained as follows: Draw a three-dimensional vegetation distribution structure map based on the edge position x, y of the herbaceous plant distribution in each area of ​​the sample plot and the height h of the herbaceous vegetation; Based on the three-dimensional vegetation distribution structure diagram, the three-dimensional model of herbaceous plants is calculated to obtain the three-dimensional diversity index of the herbaceous layer, and the formula is: ， In the formula, is the area of ​​any triangular grid in each top surface grid in the three-dimensional distribution structure diagram, A is the area of ​​the wetland sample plot, is the height of each vegetation, is the height of the highest herbaceous vegetation in the plot, is the order of herbaceous plants sorted from small to large in height, and n is the total number of herbaceous plant individuals.

7. The method for describing the diversity of multi-layer vertical spatial structure of wetland vegetation according to claim 2, characterized in that: Based on the diversity of the wetland vegetation's aboveground root structure and the diversity of the wetland vegetation's herbaceous layer structure, the diversity of the wetland vegetation's underlying structure is specifically as follows: ， in, is the root three-dimensional structure diversity index, It is the three-dimensional diversity index of the herb layer.

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