Assessment method for mangrove forest north migration adaptability

Abstract

The invention belongs to the technical field of environmental protection, and particularly discloses a mangrove forest north migration adaptability evaluation method, which comprises the steps of basic investigation and survey, evaluation index establishment, index determination, weight calculation, fitness calculation and back-stepping tracing. According to the method, a target layer and multi-level index evaluation mode is used, three-layer 16 indexes of a plant community, a water environment and a sediment environment are fused, vegetation habitat types under different conditions are considered at the same time, adaptation degree evaluation is carried out on the current situation of mangrove forest artificially introduced at middle and high latitudes by applying multiple weight calculation methods and combining adaptation degree calculation, and the evaluation accuracy is improved. Key indexes influencing mangrove forest adaptability in a sample plot are fed back in a targeted mode, professional suggestions are provided for current situation restoration of mangrove forests moved in the north, mangrove forest planting towards the north is promoted, the ecological potential is brought into full play, and a reliable evaluation basis is provided for scientific and reasonable mangrove forest resource management and control.

Description

Technical Field

[0001] The invention relates to the technical field of environmental protection, and in particular to a method for evaluating the adaptability of mangroves to northward migration. Background Art

[0002] Mangroves are woody plant communities that grow in the intertidal zones of tropical and subtropical coasts. They are highly productive and rich in biodiversity. They are the link between land and marine ecosystems and play an important role in biological protection, economic development, cultural tourism, education, etc. As one of the coastal blue carbon ecosystems and an ecological barrier for coastal cities, mangroves, known as the "coastal guards", help improve water quality and prevent waves and strengthen embankments.

[0003] Due to the impact of global warming, there is a possibility of introducing mangrove plants in mid- and high-latitude regions. Therefore, the successful northward migration of mangroves will play an important role in the restoration and protection of coastal coastlines, which is a new breakthrough. However, artificial aquaculture reclamation and sewage discharge have led to frequent eutrophication, threatening the nearshore water ecosystem, greatly reducing the self-purification capacity of mangroves, changing the structure and function of the local ecosystem, and threatening the healthy and stable development of the mangrove ecosystem. Therefore, there is an urgent need for research on the structural and functional adaptability of mid- and high-latitude mangrove ecosystems.

[0004] At present, the establishment and research of the index system for evaluating the health of mangrove ecosystems are all focused on the evaluation of the physiological and ecological conditions of mangrove plants themselves, the nitrogen and phosphorus content of water bodies, and the benthic biomass. Different competition patterns between mangrove plants and native and invasive species are not considered according to specific conditions. The monitoring of new pollutants such as microplastics is not considered in the selection of indicators, and the construction of the index system lacks comprehensiveness and integrity. At the same time, it is impossible to fully establish a feedback mechanism between the index system of mangrove health and the evaluation results, and it is impossible to accurately lock in the key indicators that affect the survival rate and adaptability of northward-migrating mangroves. Therefore, it is impossible to carry out effective and targeted construction in the ecological restoration project of mangroves in the future, and it is impossible to fundamentally improve the efficiency of coastal ecological barriers. Moreover, the current index evaluation system is only applicable to the health evaluation of low-latitude tropical mangroves, but it cannot be generalized for the artificially introduced mangrove ecosystems in mid- and high-latitudes under the dual influence of global warming and nearshore water pollution. Therefore, it is particularly important to construct a comprehensive evaluation system suitable for the adaptability of northward-migrating mangrove ecosystems. Summary of the invention

[0005] Based on the shortcomings of the existing mangrove evaluation index system and the impact of global climate change and offshore eutrophication on the adaptability of the northward-migrating mangrove ecosystem, the present invention provides an evaluation method for the northward adaptability of mangroves, so as to adjust and optimize the structural stability of the mangrove ecosystem and the ecological service function of the coastal coastline. By using the "target layer + multi-level index" evaluation method, 16 indicators of three layers of plant community, water environment and sediment environment are integrated, and vegetation habitat types in different situations are considered. A variety of weight calculation methods are used in combination with fitness calculation to evaluate the adaptability of the current status of artificially introduced mangroves in mid- and high-latitudes. The key indicators affecting the adaptability of mangroves in the sample plot are fed back in a targeted manner, which is used to provide professional suggestions for the restoration of the current status of the northward-migrating mangroves, help promote the northward planting of mangroves and give full play to their ecological potential, and provide a reliable evaluation basis for the scientific and reasonable management and control of mangrove resources.

[0006] In order to achieve the above object, the specific technical solution adopted by the present invention is as follows:

[0007] A method for assessing the adaptability of mangrove forests to the north includes the following steps:

[0008] S1. Basic survey: Investigate the natural conditions of the area, conduct preliminary surveys on climate temperature, historical landforms, hydrological conditions, and flooding environmental factors in the selected area; and record plant species and their dominance ratios, including mangrove plants, semi-mangrove plants, native plants, invasive plants, and other introduced plants, and identify the key factors that affect the physiological and ecological conditions of true mangrove and semi-mangrove plants under natural conditions;

[0009] S2. Establish evaluation indicators: As shown in the following table, fitness is the primary indicator; plant community, water environment, and sediment are secondary indicators; in plant community, biomass, growth period, canopy density, number of roots, stems, and leaves, biological enzyme activity, and carbon, nitrogen, and phosphorus components are the third-level indicators; in water environment, salinity, pH value, dissolved oxygen, and comprehensive nutritional status index are the third-level indicators; in sediment, particle size, comprehensive pollution index, organic matter content, heavy metal content, microplastic content, and benthic biomass are the third-level indicators;

[0010] Table of evaluation indexes for suitability of northward-migrating mangroves

[0011]

[0012]

[0013] S3. Determination of indicators: Sampling party, determine the specific values ​​of each indicator in the three-level indicators;

[0014] S4. Calculate weights: As shown in the following table, calculate the weights of each indicator in the secondary and tertiary indicators; select 2-3 methods for comprehensive weight calculation based on conventional weight calculation methods, such as hierarchical analysis method, fuzzy analysis method, neural network method, etc., to avoid the error caused by subjective selection of a single weight method;

[0015] Weight table for evaluation of suitability of northward-migrating mangroves

[0016]

[0017] S5. Calculate fitness: Assign values ​​to each indicator through expert scoring, then multiply the comprehensive weight of each indicator by the assigned value and weight it, and calculate the fitness of the northward-migrating mangrove ecosystem according to formula (5) (the adaptability of the northward-migrating mangroves is evaluated by fitness, the higher the fitness, the better the adaptability):

[0018]

[0019] Where: n is the number of evaluation indicators, n is a positive integer; Pij is the value of the jth indicator in the i-th indicator layer; Wij is the comprehensive weight of the jth indicator in the i-th indicator layer.

[0020] Preferably, the method for evaluating the adaptability of mangroves to the north also includes: Step S6. Reverse tracing: combining the preliminary basic information survey and the reverse derivation of the weights of each stratified indicator, tracing back the key indicator items affecting the adaptability of mangroves in the sample plot, and providing professional suggestions for the current restoration of the northward-migrated mangroves.

[0021] Preferably, in step S1, if more than one mangrove plant species is found in the sample plot, the weight values ​​of the secondary index plant community and its tertiary index need to be calculated for different plant species. a , A b ...; The weight values ​​of the third-level indicators are further divided into W a11 ~W a16 , W b11 ~W b16 …….

[0022] Preferably, in step S4, the weights of various indicators are calculated as comprehensive weights, which are obtained by combining subjective weights and objective weights. The calculation method of the comprehensive weights is as follows:

[0023] S41. The function shown in formula (3) is established with the purpose of minimizing the sum of squares of the deviations among the subjective weight, the objective weight and the combined weight:

[0024]

[0025] Where: W 综i is the comprehensive weight of the i-th indicator; W主i is the subjective weight value of the indicator; W 客i is the objective weight value of the indicator;

[0026] S42. Formula (3) combined with formula (4) to obtain the comprehensive weight W 综i :

[0027] W 综i =θW 主i +(1-θ)W 客i (4)

[0028] Where: θ is the subjective preference coefficient, that is, the proportion of the subjective value in the comprehensive weight.

[0029] Preferably, the subjective weight is obtained by using a hierarchical analysis method, and the objective weight is obtained by using an entropy method.

[0030] Preferably, in step S5, the fitness average of at least three samples is used as the result.

[0031] This paper focuses on the current status of artificial introduction of mangroves in mid- and high-latitudes under the background of global warming. It uses 16 indicators in three layers of plant communities, water environment and sediment environment to evaluate the adaptability of mangroves to the north through fitness calculation, and combines basic information and model weights to trace back the key indicators that affect the adaptability of mangroves in the sample plot, and puts forward suggestions for the protection and management of the resources of the northward-migrating mangrove ecosystem. On the one hand, it can effectively evaluate the health level of the mangrove ecosystem and further improve the survival rate and adaptability of mangrove plants in mid- and high-latitude regions; on the other hand, it helps to scientifically and rationally manage mangrove resources, making it easier for enterprises to carry out subsequent governance projects based on these evaluation results and suggestions. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 : Flow chart of the method for evaluating the adaptability of mangroves to the northward migration described in the present invention. DETAILED DESCRIPTION

[0033] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0034] Example 1

[0035] A method for assessing the adaptability of mangrove forests to the northward migration, the process is as follows: Figure 1 As shown, the specific steps include:

[0036] S1. Basic research:

[0037] Today, the intensification of global warming has become a favorable boost to the northward migration of mangroves. Introducing mangrove plants in the Jiangsu, Zhejiang and Shanghai areas near 31° north latitude has become a new trend. However, along with global climate change, it has caused a series of chain reactions such as increased frequency of extreme weather, changes in ocean circulation and upwelling. In order to cope with these ecological crises, helping mangrove ecosystems adapt and settle in mid- and high-latitudes has become an effective exploration to cope with extreme climate and beach erosion.

[0038] Therefore, we conducted a field survey on the habitat status of the mangrove ecosystem in Dongtan, Lingang, Shanghai, and carried out preliminary research on the constituency. We learned that: Shanghai Lingang has a monsoon climate with an average temperature of 17.6℃, hot summers and cold winters; it is located in the middle and lower reaches of the Yangtze River plain and is formed by silt alluvial deposits; the precipitation is 1173.4 mm, and the rainy season is concentrated in May-September; the river channel is more than 20,000 kilometers long, and the river network density is 3-4 kilometers per square kilometer on average; the native plants include reeds, the introduced plants include Scirpus maritima, and the invasive plants include Spartina alterniflora.

[0039] S2. Establish evaluation indicators: Establish 16 indicators in three levels as shown in the following table:

[0040]

[0041]

[0042] S3. Determination of indicators: Set up a sampling plot with a radius of about 5m to measure the specific values ​​of each indicator in the three-level indicators; the method is as follows:

[0043] S31. Determination of 6 index values ​​in plant communities:

[0044] Biomass: One plant was randomly harvested in the plot using the whole-harvest method, and the harvested plant was dried at 70°C to a constant weight, and its total dry mass was recorded.

[0045] Growth period: usually refers to the age of seedlings. One growth cycle is considered one unit of seedling age, and completing one growth cycle is one age, which is called a one-year-old.

[0046] Canopy closure: Use the visual method to set up multiple sample points. By looking up vertically at each position, determine whether the sample point is covered by the tree crown. Count the number of covered sample points and substitute the formula: Canopy closure = number of sample points covered by the tree crown / total number of sample points.

[0047] Number of roots, stems and leaves: One plant was randomly harvested within the plot using the full harvest method, and the number of roots, stems and leaves of the harvested plant was recorded separately.

[0048] Biological enzyme activity: Superoxide dismutase (SOD) activity was determined according to the method of Giannopolitis and Ries (1977), with 50% inhibition of photoreduction of nitroblue tetrazolium as one unit of enzyme activity; catalase (CAT) activity was determined according to the method of Chance and Maehly (1955), with OD per minute. 240 The amount of enzyme required for a change of 0.01 was defined as one unit of enzyme activity; the peroxidase (POD) activity was calculated according to the method of Chen Yizhu and Wang Yirou (1989) and the OD value per minute was determined. 470 A change of 0.01 was defined as 1 unit of enzyme activity. The activity of ascorbic acid (AsA) peroxidase (APX) was determined according to the method of Nakano and Asada (1981), with the amount of enzyme that oxidizes 1 μmol AsA per min as 1 unit of enzyme activity. The activity of glutathione reductase (GR) was determined according to the method of Foyer and Halliwell (1976), with the OD value within 3 min as 1 unit. 340 The change in represents one unit of enzyme activity.

[0049] Carbon, nitrogen and phosphorus content: A plant was randomly harvested in the sample plot using the full harvest method. The harvested plants were dried and crushed into powder and sieved. The total carbon was determined by wet burning method (potassium dichromate volumetric method). The total nitrogen and total phosphorus were determined by H2SO4-H2O2 digestion method. After filtering the digestion liquid, the total nitrogen content was determined by Kjeldahl nitrogen analyzer, and the total phosphorus content was determined by molybdenum antimony colorimetric method.

[0050] S32. Determination of 4 index values ​​in water environment:

[0051] During the experiment, surface water samples were collected using a water sampler or sampling bottle, filtered and concentrated through a plankton net, and water environment indicators including salinity, pH value, dissolved oxygen, and comprehensive nutrient status index (total nitrogen, total phosphorus, ammonia nitrogen, nitrate nitrogen, and water quality COD) were measured.

[0052] Salinity, pH value, dissolved oxygen: Use a salt content meter, pH detector, and dissolved oxygen meter to record the measured salinity (‰), pH value, and dissolved oxygen (mg / L) data separately.

[0053] Comprehensive nutritional status index: Using ultraviolet spectrophotometer and other instruments, using spectrophotometry, the measured chlorophyll a (chla), total phosphorus (TP), total nitrogen (TN), transparency (SD), permanganate index (CODMn) are substituted into formula (1) to calculate the comprehensive nutritional status index TLI (∑) and obtain the comprehensive water pollution index. The specific formula is as follows:

[0054]

[0055] Where: TLI (∑) is the comprehensive nutritional status index; Wj is the relevant weight of the nutritional status index of the jth parameter; TLI(j) is the nutritional status index representing the jth parameter; W j The calculation methods of TLI(j) refer to the Technical Regulations on Evaluation Methods and Classification of Eutrophication of Lakes (Reservoirs) formulated by the China Environmental Monitoring Center.

[0056] S33. Determination of 6 index values ​​in sediment:

[0057] For the soil in the rhizosphere layer of mangrove plants and the 0-10 cm surface layer of the bare beach area, the plum blossom sampling method was used to obtain sediment mud samples, which were transported back to the laboratory for sample pretreatment and the physical and chemical properties of the sediments were measured, including particle size, comprehensive pollution index, organic matter content, heavy metal content, microplastic content, and benthic biomass.

[0058] Particle size: Use a particle size analyzer to measure the particle size of sediment.

[0059] Comprehensive pollution index: Substitute into formula (2) to obtain the comprehensive pollution index P, and judge the pollution degree of the sediment environment in the selected area. The specific formula is as follows:

[0060]

[0061] Where: n is the type of pollutant; P is the comprehensive pollution index; P j It is the ratio of the measured value of the jth pollutant to the evaluation standard value, calculated according to the "Surface Water Environmental Quality Standard" (GB3838-2002).

[0062] Organic matter content: The oxidation amount of potassium dichromate is determined by measuring the back-titration amount of ferrous sulfate or the absorbance value of trivalent chromium after reduction, thereby measuring the organic carbon content in the soil and calculating the organic matter content.

[0063] Heavy metal content: The contents of Cr, Ni, Zn, Cu, Pb, and Cd in the filtered sediment samples were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES).

[0064] Microplastic content: According to the method proposed by NOAA, Fenton reagent was used for digestion and 1.6 g / mL ZnCl2 solution was used for separation. Stereo microscope and Fourier transform micro-infrared spectroscopy were used to identify the type, particle size, color and shape of microplastics.

[0065] Benthic biomass: The biomass of benthic organisms was measured by wet weight method (g / m 2 ), and simultaneously identify and count various organisms (ind / m 2 )

[0066] S4. Calculate weights: Calculate the weights of each indicator in the secondary and tertiary indicators as shown in the following table;

[0067]

[0068]

[0069] The weight calculation of each indicator is a comprehensive weight calculated by combining the analytic hierarchy process and the entropy method, so as to give full play to the advantages of subjective weight and objective weight, avoid the shortcomings of various weight determination methods, and make the evaluation results more reliable. The specific methods are as follows:

[0070] S41. The function shown in formula (3) is established with the purpose of minimizing the sum of squares of the deviations among the subjective weight, the objective weight and the combined weight:

[0071]

[0072] Where: W 综i is the comprehensive weight of the i-th indicator; W 主i is the subjective weight value of the indicator; W 客i is the objective weight value of the indicator;

[0073] S42. Formula (3) combined with formula (4) to obtain the comprehensive weight W 综i :

[0074] W 综i =θW 主i +(1-θ)W 客i (4)

[0075] Where: θ is the subjective preference coefficient, that is, the proportion of the subjective value in the comprehensive weight.

[0076] S5. Calculate fitness: Repeat the sampling three times, obtain the measured values ​​of plants, water samples and sediment samples in the three sample plots, and then score the above indicators and assign a value to each indicator; then multiply the comprehensive weight of each indicator by the assigned value and weight it, and calculate the fitness of the northward mangrove ecosystem according to formula (5):

[0077]

[0078] Where: n is the number of evaluation indicators, n is a positive integer; P ij Assign a value to the jth indicator of the i-th indicator layer; W ij is the comprehensive weight of the jth indicator in the i-th indicator layer.

[0079] The fitness of the three samples was calculated separately, and the average was taken as the final fitness result. The adaptability of the northward-migrated mangroves was evaluated by the fitness score. The higher the fitness score, the better the adaptability.

[0080] S6. Backtracking: Combined with the previous basic information survey and the reverse deduction of the weights of each layered indicator, the key indicator items that affect the adaptability of mangroves in the sample plot are traced back to provide professional suggestions for the restoration of the current status of the northward-migrated mangroves. For example, if the comprehensive weight W24 of the fourth indicator (B4 comprehensive nutritional status index) in the second indicator layer (B water environment indicator layer) accounts for the largest proportion and the indicator value P24 is the lowest, it is judged that the indicator has the highest degree of influence on the adaptability of the northward-migrated mangrove ecosystem in the sample plot, and finally the key indicator layer that affects the adaptability of mangroves in the sample plot - water environment indicator B and key indicator item - comprehensive nutritional status index B4 are determined, and then professional suggestions are provided for the restoration of the current status of the northward-migrated mangroves, pointing out that the discharge of aquaculture wastewater and domestic sewage should be strictly controlled, and biological measures should be taken to alleviate offshore eutrophication, so as to provide a reference for ensuring the health and stability of the coastal ecological barrier in the Yangtze River Delta region and maintaining the safety of the mangrove ecosystem.

[0081] Example 2

[0082] This embodiment provides a more specific application example of the method for evaluating the adaptability of mangroves to the northward migration.

[0083] Annual sampling was conducted in the mangrove planting demonstration area of ​​Shanghai Nanhui Dongtan Wetland, and the results were averaged. Then case calculations and evaluations were performed based on the model, and the adaptability of Kandelia candel was evaluated according to the corresponding indicators and weight system, as follows:

[0084] 1. Index system

[0085] 1.1 Scores and corresponding ranges of the three-level sixteen indicators

[0086]

[0087]

[0088]

[0089] 1.2 Measurement values ​​of sixteen indicators at three levels

[0090] For each third-level indicator, the average data actually measured by annual sampling in the mangrove planting demonstration area of ​​Shanghai Nanhui Dongtan Wetland is as follows:

[0091]

[0092]

[0093] According to the measured values ​​of each indicator, specific values ​​are assigned to each indicator in accordance with the previous range table.

[0094] 2. Invite 10 experts from relevant industries and technical personnel from engineering demonstration enterprises to score the indicators according to their importance. An anonymous questionnaire scoring method is adopted to collect the expert scoring data. The objective weight is obtained by processing the values ​​of each indicator obtained from the literature search using the entropy method. Substituting into formulas (3) and (4), the comprehensive weight (W 综 ), the weight values ​​are shown in the following table:

[0095]

[0096]

[0097] 3. Comprehensive score (fitness)

[0098] Substitute the values ​​of each indicator obtained in 1 and the weight values ​​of each indicator obtained in 2 into formula (5) to calculate the fitness, and the obtained comprehensive score is 6.485.

[0099] 4. Evaluation results

[0100] The comprehensive score classification is as follows:

[0101] Score range 0-2 3-5 6-8 9-10 Evaluation results Unsuitable More suitable suitable Very suitable

[0102] The suitability level was determined. According to the comprehensive score of 6.485, the Shanghai Nanhui Dongtan Wetland Mangrove Planting Demonstration Area was evaluated as "suitable". Specifically, the vegetation coverage rate of coastal wetlands is high, the ecosystem is relatively stable, and the biodiversity is good, but there are sparse vegetation in some local areas. The content of nutrient elements in plants is relatively moderate, the activity of functional enzymes fluctuates slightly, and the metabolic level is in good condition. The dissolved oxygen content of the wetland water environment is average, the water pollution index is moderate, and the water quality is basically maintained in a suitable pH range, which is suitable for the survival and reproduction of aquatic organisms. The sediment state is acceptable, but there may be slight accumulation of pollutants.

[0103] 5. Provide suggestions

[0104] According to the assessment results, it is recommended to take the following measures to restore the current status of mangroves in Shanghai Nanhui Dongtan Wetland: 1) Enhance vegetation coverage and promote vegetation growth in sparse areas through replanting and natural restoration; 2) Regularly monitor water quality, especially dissolved oxygen and pollution index, to ensure the health of the water environment; 3) Strengthen soil improvement, increase organic matter content, and improve sediment status; 4) Protect and restore biodiversity and promote the improvement of benthic habitats to enhance ecosystem stability. Through comprehensive measures, the ecological functions of mangroves can be further improved.

[0105] This specific implementation is only an explanation of the present invention, not a limitation of the present invention. Any changes made by those skilled in the art after reading the specification of the present invention will be protected by the patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A method for assessing the adaptability of mangrove forests to the north, characterized by: The following steps are involved: S1. Basic survey: Investigate the natural conditions of the area, conduct preliminary surveys on climate temperature, historical landforms, hydrological conditions, and flooding environmental factors in the selected area; and record plant species and their dominance ratios, including mangrove plants, semi-mangrove plants, native plants, invasive plants, and other introduced plants, and identify the key factors that affect the physiological and ecological conditions of true mangrove and semi-mangrove plants under natural conditions; S2. Establish evaluation indicators: fitness as the primary indicator; plant community, water environment, and sediment as secondary indicators; in plant community, biomass, growth period, canopy density, number of roots, stems, and leaves, enzyme activity, and carbon, nitrogen, and phosphorus components as the third-level indicators; in water environment, salinity, pH value, dissolved oxygen, and comprehensive nutrient status index as the third-level indicators; in sediment, particle size, comprehensive pollution index, organic matter content, heavy metal content, microplastic content, and benthic biomass as the third-level indicators; S3. Determination of indicators: Sampling party, determine the specific values ​​of each indicator in the three-level indicators; S4. Calculate weights: Calculate the weights of each indicator in the secondary and tertiary indicators and perform consistency checks; S5. Calculate fitness: Assign values ​​to each indicator through expert scoring, then multiply the comprehensive weight of each indicator by the assigned value and weight it, and calculate the fitness of the northward mangrove ecosystem according to formula (5): Where: n is the number of evaluation indicators, n is a positive integer; P ij Assign a value to the jth indicator of the i-th indicator layer; W ij is the comprehensive weight of the jth indicator in the i-th indicator layer.

2. The method for evaluating the adaptability of mangrove forests to the northward migration according to claim 1, characterized in that: It also includes step S6. Back-tracing: combining the previous basic information survey and the reverse deduction of the weights of each stratified indicator, tracing the key indicator items affecting the adaptability of mangroves in the sample site, and providing professional suggestions for the current restoration of the northward-migrated mangroves.

3. The method for evaluating the adaptability of mangrove forests to the northward migration according to claim 1, characterized in that: In step S1, if more than one mangrove plant species is found in the sample plot, the weight values ​​of the secondary indicator plant community and its tertiary indicator need to be calculated for different plant species.

4. The method for evaluating the adaptability of mangrove forests to the northward migration according to claim 1, characterized in that: In step S4, the weights of various indicators are calculated as comprehensive weights, which are obtained by combining subjective weights and objective weights. The calculation method of the comprehensive weights is as follows: S41. The function shown in formula (3) is established with the purpose of minimizing the sum of squares of the deviations among the subjective weight, the objective weight and the combined weight: Where: W 综i is the comprehensive weight of the i-th indicator; W 主i is the subjective weight value of the indicator; W 客i is the objective weight value of the indicator; S42. Formula (3) combined with formula (4) to obtain the comprehensive weight W 综i : IN 综i =θW 主i +(1-θ)W 客i (4) Where: θ is the subjective preference coefficient, that is, the proportion of the subjective value in the comprehensive weight.

5. The method for evaluating the adaptability of mangrove forests to the northward migration according to claim 4, characterized in that: The subjective weight is obtained by using the hierarchical analysis method, and the objective weight is obtained by using the entropy method.

6. The method for evaluating the adaptability of mangrove forests to the northward migration according to claim 1, characterized in that: In step S5, the fitness average of at least three samples is taken as the result.

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