Submerged plant water quality sediment adaptability evaluation method and ecological restoration decision-making method

Abstract

The invention relates to submerged plant water quality sediment adaptability evaluation, in particular to a submerged plant water quality sediment adaptability evaluation method and an ecological restoration decision-making method.The submerged plant water quality sediment adaptability evaluation method comprises the following steps that 1, the weight of indexes is adjusted according to measured values of parameters; step 2, calculating the utility value of the index; and step 3, calculating an adaptability index according to the index and the weight thereof. According to the method, environmental stress changes can be responded in real time through the dynamic weight distribution model, the multi-parameter synergistic effect of the water quality factor, the sediment factor and the plant growth factor is comprehensively considered, utility value quantification is carried out by utilizing a membership function, the adaptability index is output, and a grading decision scheme is formed; according to the method, the adaptability of the submerged plants is converted from qualitative description to quantitative decision, the submerged plants can be scientifically matched with water quality-bottom mud conditions of specific water areas, a standardized and replicable technical tool can be provided for lake ecological restoration, and therefore the success rate and cost effectiveness of restoration engineering are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of submerged plant sediment adaptability assessment technology, and in particular to a method for assessing the adaptability of submerged plant sediment and an ecological restoration decision-making method. Background Technology

[0002] Submerged plants, as essential basic organisms for maintaining the stability of lake ecosystems, play an irreplaceable role in water purification, sediment stabilization, and nutrient cycling. Therefore, how to scientifically assess the adaptability of submerged plants under specific water quality and sediment conditions, and thus provide a basis for decision-making in lake ecological restoration, has become a key issue that urgently needs to be addressed in current research and engineering practice.

[0003] Current research on the adaptability of submerged plants is relatively limited and generally suffers from the following shortcomings: First, the assessment dimensions are singular. Traditional methods often focus on single-factor analysis of water quality factors (such as transparency, nitrogen and phosphorus concentrations) or sediment factors (such as organic matter content), failing to comprehensively reflect the complex interactions between water quality, sediment, and plant physiological responses. Second, most existing methods employ fixed-weight models, which cannot dynamically adjust the importance of different environmental factors under various ecological stresses. For example, when sediment is in a highly reducing state (Eh < -200 mV), the impact of sediment factors on the survival of submerged plants is significantly enhanced, but current technologies have failed to adaptively adjust the weights according to environmental conditions. Finally, existing assessments rely heavily on qualitative judgments based on expert experience, lacking quantitative grading standards. This leads to ambiguous decision-making criteria in ecological restoration projects, and in practical applications, the mortality rate of submerged plants often reaches 40% to 60%, severely hindering restoration effectiveness.

[0004] Therefore, there is an urgent need to propose an adaptive assessment method that can comprehensively consider the synergistic relationship of multiple parameters such as water quality, bottom sediment, and submerged plants. Through dynamic weight adjustment, utility value calculation, and the establishment of quantitative grading standards, a scientific evaluation of the adaptability of submerged plants and an optimized decision-making process for restoration plans can be achieved, thereby providing standardized and operable technical support for the ecological restoration of shallow lakes on plateaus. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for assessing the adaptability of submerged plants to water quality sediment and a method for ecological restoration decision-making.

[0006] This invention is achieved through the following technical solution: A method for assessing the adaptability of submerged plants to aquatic sediment, comprising the following steps: Step 1: Adjust the weight of the indicators based on the measured values ​​of the parameters; Step 2: Calculate the utility value of the indicator; Step 3: Calculate the adaptability index based on the indicators and their weights.

[0007] Preferably, the indicators include water quality factors, sediment factors, and plant growth factors; The parameters of the water quality factors include transparency and total phosphorus; The parameters of the sediment factor include organic matter content, total nitrogen, and redox potential; The parameters of the plant factors include biomass growth rate, root activity, and chlorophyll a.

[0008] Preferably, the initial weight of the water quality factor is 40%, the initial weight of the sediment factor is 30%, and the initial weight of the plant growth factor is 30%.

[0009] Preferably, "adjusting the weight of the index according to the measured value of the parameter" includes the following steps: When the transparency is less than 60cm, the weight of the water quality factor increases by 15%-20%; and / or When total phosphorus is greater than 0.2 mg / L, the weight of the water quality factor increases by 5%-10%; and / or When the organic matter content is greater than 15%, the weight of the sediment factor increases by 8%-10%; and / or When the redox potential is less than -200mV, the weight of the sediment factor increases by 10%-15%; and / or When the biomass growth rate declines for two consecutive weeks, the weight of the plant factor increases by 15%-20%; and / or When root activity is less than 0.4 mg·g -1 ·h -1 At that time, the weight of the plant factor increases by 12%-15%; and / or When the chlorophyll decreases by more than 30%, the weight of the plant factor increases by 10%-12%.

[0010] Preferably, "adjusting the weight of the index according to the measured value of the parameter" further includes the following steps: The weights of the three adjusted indicators are normalized so that the sum of the weights of the three adjusted indicators is 100%.

[0011] Preferably, "calculating the utility value of the indicator" includes the following steps: Calculate the utility value of the parameters of the indicator; Assign weights to the parameters; The utility value of the index is calculated based on the utility value of the parameters and the parameters themselves.

[0012] Preferably, "calculating the utility value of the parameters of the indicator" includes the following steps: The formula for calculating the utility value of transparency is:

[0013] In the formula, The utility value of the transparency. The measured value of the transparency; The formula for calculating the effectiveness of the redox potential is as follows:

[0014] In the formula, The effective value of the redox potential is... This refers to the measured value of the redox potential; The formula for calculating the utility value of the biomass growth rate is:

[0015] In the formula, The utility value of the biomass growth rate. This refers to the measured value of the biomass growth rate; The formula for calculating the utility value of root vitality is as follows:

[0016] In the formula, The utility value of the root vitality. The measured value of the root vitality; The formula for calculating the utility value of chlorophyll a is as follows:

[0017] In the formula, The utility value of chlorophyll a is given. The measured value of chlorophyll a is given.

[0018] Preferably, the formula for calculating the adaptability index is:

[0019] In the formula, For adaptability index, The weights of water quality factors, The normalized value of the membership function for the water quality factor. The weights of the sediment factors, This represents the normalized value of the membership function for the sediment factor. The weights of plant factors, This represents the normalized value of the membership function for plant factors.

[0020] An ecological restoration decision-making method, comprising the following steps: Decision-making schemes are determined based on the adaptability index; The adaptability index is the adaptability index obtained according to the above-mentioned method for assessing the adaptability of submerged plant sediment in water quality.

[0021] Preferably, "determining a decision scheme based on the adaptability index" includes the following steps: When the fitness index is greater than 0.8, direct planting is permitted; When the adaptability index is between 0.6 and 0.8, the plant is planted after environmental improvement; When the fitness index is less than 0.6, abandon planting or initiate an alternative program.

[0022] The beneficial effects of this invention are: This invention provides a method for assessing the adaptability of submerged plants to water quality and sediment. This method utilizes a dynamic weighting model to respond in real-time to changes in environmental stress, comprehensively considering the synergistic effects of multiple parameters, including water quality factors, sediment factors, and plant growth factors. It quantifies utility values ​​using membership functions, outputs an adaptability index, and forms a tiered decision-making scheme. Compared to existing technologies, this method overcomes the shortcomings of traditional assessment methods, such as single assessment dimensions, ineffective fixed weights, and reliance on empirical judgment. It transforms the assessment of submerged plant adaptability from qualitative description to quantitative decision-making. This method not only scientifically matches submerged plants with specific water quality and sediment conditions, avoiding indiscriminate planting and high mortality rates, but also provides standardized and replicable technical tools for lake ecological restoration, thereby significantly improving the success rate and cost-effectiveness of restoration projects. Attached Figure Description

[0023] Figure 1 This is a flowchart of the steps in the method for evaluating the adaptability of submerged plants to water quality sediment according to the present invention. Detailed Implementation

[0024] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and preferred embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0025] This invention provides a method for assessing the adaptability of submerged plants to water quality and sediment. The indicators in this method include water quality factors, sediment factors, and plant growth factors. Water quality factors include transparency and total phosphorus. Sediment factors include organic matter content, total nitrogen, and redox potential. Plant factors include biomass growth rate, root activity, and chlorophyll a. The initial weights for water quality factors are 40%, sediment factors are 30%, and plant growth factors are 30%.

[0026] The method includes the following steps: Step 1: Adjust the weight of the index based on the measured value of the parameter.

[0027] This step adjusts the weights of the indicators based on the measured values ​​of the parameters, taking into account the characteristics of the plateau environment. Specifically, this step includes the following steps: When the transparency is less than 60 cm, the weight of the water quality factor should be increased by 15%-20%. Transparency is a core indicator reflecting the clarity of water. When the transparency is below 60 cm, it means that the water is highly turbid, light cannot easily penetrate the water layer, the photosynthesis of submerged plants is severely inhibited, and they may even be unable to meet their physiological needs. Therefore, it is necessary to increase the weight of the water quality factor.

[0028] When total phosphorus exceeds 0.2 mg / L, the weight of the aforementioned water quality factors increases by 5%-10%. Specifically, when the total phosphorus concentration in water exceeds 0.2 mg / L, it indicates a risk of eutrophication or hypereutrophication, significantly impacting the survival and adaptability of submerged plants. This can lead to algal blooms and decreased transparency, but is accompanied by the penetrating effect of ultraviolet radiation in shallow water environments. Studies have shown that high nutrient levels combined with strong ultraviolet radiation can amplify the photo-oxidative stress and toxic effects on submerged plants. Therefore, it is necessary to increase the weight of water quality factors.

[0029] When the organic matter content is greater than 15%, the weight of the sediment factor increases by 8%-10%. An organic matter content exceeding 15% in the sediment indicates that the sediment is rich in biodegradable substances. Under anoxic or reducing conditions in the water, the decomposition of these organic substances consumes a large amount of dissolved oxygen and produces harmful reducing substances such as methane and hydrogen sulfide. These products not only directly poison the roots of submerged plants but also disrupt the oxygen exchange environment between the plants and the sediment, inhibiting normal plant growth. Therefore, it is necessary to increase the weight of the sediment factor.

[0030] When the redox potential is less than -200 mV, the weight of the sediment factor is increased by 10%-15%. Redox potential (Eh) reflects the oxidation / reduction state of sediments. When the Eh value is below -200 mV, it indicates that the sediment environment has entered a strongly reducing state, with anoxic or even anaerobic reactions dominating. At this time, reducing substances (such as hydrogen sulfide, methane, ferrous ions, etc.) will be produced in the sediment. These substances have a strong toxic effect on the roots of submerged plants, severely inhibiting plant growth and survival. Therefore, it is necessary to increase the weight of the sediment factor.

[0031] When the biomass growth rate declines for two consecutive weeks, the weight of the plant factor should be increased by 15%-20%. The biomass growth rate represents the rate of biomass change per unit time for submerged plants. If this indicator declines for two consecutive weeks, it indicates that plant growth is being persistently inhibited, not just a short-term fluctuation. This often means that external environmental stresses (such as water quality deterioration, sediment toxicity, and insufficient light) have exceeded the plant's self-regulating capacity, and the plant's adaptability is entering a declining phase. Therefore, it is necessary to increase the weight of the plant factor.

[0032] When root activity is less than 0.4 mg·g -1 ·h -1 At this time, the weight of the plant factor increases by 12%-15%. Root activity represents the activity of plant root respiration, metabolism, and enzymatic reactions. If it is below 0.4 mg / g... -1 ·h -1 This indicates a significant decline in the plant's root system's ability to absorb nutrients and exchange substances, making it difficult to maintain normal growth and recovery processes. Therefore, it is necessary to increase the weight of plant factors.

[0033] When the chlorophyll content decreases by more than 30%, the weight of the plant factors is increased by 10%-12%. Chlorophyll a (Chl-a) is a core indicator of the photosynthetic efficiency of submerged plants. If a decrease in Chl-a content exceeding 30% is detected within a certain monitoring period, it indicates that the plant's photosynthetic system is severely inhibited, its carbon fixation and energy conversion capabilities are significantly weakened, and it is under physiological stress. Therefore, it is necessary to increase the weight of plant factors.

[0034] Furthermore, after adjusting the indicator weights according to the above steps, the sum of the weights of the three indicators is usually not 100%. Therefore, it is necessary to normalize the weights of the three indicators after adjustment so that the sum of the weights of the three indicators after adjustment is 100%.

[0035] Step 2: Calculate the utility value of the indicator. This step specifically includes the following steps: Step 2.1, calculate the utility value of the index parameters. This step includes the following steps: The formula for calculating the utility value of transparency is:

[0036] In the formula, The utility value of the transparency. The measured value of the transparency; The formula for calculating the effectiveness of the redox potential is as follows:

[0037] In the formula, The effective value of the redox potential is... This refers to the measured value of the redox potential; The formula for calculating the utility value of the biomass growth rate is:

[0038] In the formula, The utility value of the biomass growth rate. This refers to the measured value of the biomass growth rate; The formula for calculating the utility value of root vitality is as follows:

[0039] In the formula, The utility value of the root vitality. The measured value of the root vitality; The formula for calculating the utility value of chlorophyll a is as follows:

[0040] In the formula, The utility value of chlorophyll a is given. The measured value of chlorophyll a is given.

[0041] Step 2.2: Assign weights to the parameters. Specifically, the sum of the weights of multiple parameters for the same metric should be 100%.

[0042] Step 2.3: Calculate the utility value of the index based on the utility value of the parameters and the parameters themselves.

[0043] Step 3: Calculate the adaptability index based on the aforementioned indicators and their weights. The formula for calculating the adaptability index is:

[0044] In the formula, For adaptability index, The weights of water quality factors, The normalized value of the membership function for the water quality factor. The weights of the sediment factors, This represents the normalized value of the membership function for the sediment factor. The weights of plant factors, This represents the normalized value of the membership function for plant factors.

[0045] Step 4: Determine the decision-making scheme based on the adaptability index. This specifically includes the following steps: When the fitness index is greater than 0.8, direct planting is permitted; When the adaptability index is between 0.6 and 0.8, the plant is planted after environmental improvement; When the adaptability index is less than 0.6, planting should be abandoned or an alternative program should be initiated. Specifically, measures such as species replacement, emergency treatment of sediment, and improving transparency can be adopted.

[0046] The detailed steps of this method are described below with reference to specific embodiments.

[0047] Step 1: Adjust the weight of the index based on the measured value of the parameter.

[0048] The initial weights of water quality factors are 40%, sediment factors are 30%, and plant growth factors are 30%, with the sum of the weights of the three indicators being 100%.

[0049] The measured parameter values ​​for this embodiment are shown in the table below: ; The measured value of transparency is 42.5cm. The trigger condition for adjusting the transparency index is less than 60cm. Therefore, it is necessary to adjust the weight of the water quality factor corresponding to transparency. The specific adjustment value is to increase the weight by 20%, that is, 40%+20%=60%.

[0050] Next, the weights of the three indicators are normalized so that the sum of the adjusted weights is 100%. The specific calculation method is as follows: Normalization of water quality factor weights: 60% / (60% + 30% + 30%) ≈ 50% Normalized weighting of sediment factors: 30% / (60% + 30% + 30%) ≈ 25% Normalization of plant growth factor weights: 30% / (60% + 30% + 30%) ≈ 25% Step 2: Calculate the utility value of the indicator.

[0051] For water quality factors, the utility values ​​of transparency and total phosphorus are first calculated. In this embodiment, the utility value of transparency is (42.5-30) / (60-30)≈0.417, and the utility value of total phosphorus is 0.8. Next, the parameter weights of the water quality factors are assigned. In this embodiment, the weight of transparency is 60%, and the weight of total phosphorus is 40%. Then, the utility value of the water quality factors is calculated as 0.6×0.417+0.4×0.8≈0.57.

[0052] For sediment factors, the utility values ​​of redox potential and organic matter content are first calculated. In this embodiment, the utility value of redox potential is (-100+200) / (0+200)×0.5≈0.75; the utility value of organic matter content is (15-10) / (15-5)×0.2+0.8≈0.9. Then, the parameter weights of the sediment factors are assigned. In this embodiment, the weight of redox potential is 60%, and the weight of organic matter content is 40%. Then, the utility value of the sediment factors is calculated: 0.6×0.75+0.4×0.9≈0.81.

[0053] For plant growth factors, the utility values ​​of biomass growth rate, root activity, and chlorophyll a are first calculated. In this embodiment, the utility value of biomass growth rate is 10 / 50 × 1.0 ≈ 0.2; the utility value of root activity is 1; and the utility value of chlorophyll a is 2.0 / 3.5 × 1.0 ≈ 0.571. Then, the parameter weights of the plant growth factors are assigned. In this embodiment, the weight of biomass growth rate is 30%, the weight of root activity is 40%, and the weight of chlorophyll a is 30%. Finally, the utility values ​​of the plant growth factors are calculated as 0.3 × 0.2 + 0.4 × 1.0 + 0.3 × 0.571 ≈ 0.591.

[0054] Step 3, calculate the fitness index: 50%×0.570+25%×0.81+25%×0.591=0.636.

[0055] Step 4: Determine the decision-making plan based on the adaptability index. In this embodiment, the adaptability index is 0.636, which belongs to "moderate adaptability". The decision-making plan is to plant after improvement, and the measures include: sediment oxidation: adding calcium peroxide to raise Eh to above -100mV. Transparency improvement: adding microbial agents to improve transparency.

[0056] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for assessing the adaptability of submerged plants to aquatic sediment, characterized in that, Includes the following steps: Step 1: Adjust the weight of the indicators based on the measured values ​​of the parameters; Step 2: Calculate the utility value of the indicator; Step 3: Calculate the adaptability index based on the indicators and their weights.

2. The method for assessing the adaptability of submerged plants to water quality sediment according to claim 1, characterized in that, The indicators include water quality factors, sediment factors, and plant growth factors. The parameters of the water quality factors include transparency and total phosphorus; The parameters of the sediment factor include organic matter content, total nitrogen, and redox potential; The parameters of the plant factors include biomass growth rate, root activity, and chlorophyll a.

3. The method for assessing the adaptability of submerged plants to aquatic sediment according to claim 2, characterized in that, The initial weights of the water quality factors are 40%, the initial weights of the sediment factors are 30%, and the initial weights of the plant growth factors are 30%.

4. The method for assessing the adaptability of submerged plants to water quality sediment according to claim 3, characterized in that, "Adjusting the weights of indicators based on the measured values ​​of parameters" includes the following steps: When the transparency is less than 60cm, the weight of the water quality factor increases by 15%-20%; and / or When total phosphorus is greater than 0.2 mg / L, the weight of the water quality factor increases by 5%-10%; and / or When the organic matter content is greater than 15%, the weight of the sediment factor increases by 8%-10%; and / or When the redox potential is less than -200mV, the weight of the sediment factor increases by 10%-15%; and / or When the biomass growth rate declines for two consecutive weeks, the weight of the plant factor increases by 15%-20%; and / or When root activity is less than 0.4 mg·g -1 ·h -1 At that time, the weight of the plant factor increases by 12%-15%; and / or When the chlorophyll decreases by more than 30%, the weight of the plant factor increases by 10%-12%.

5. The method for assessing the adaptability of submerged plants to water quality sediment according to claim 4, characterized in that, "Adjusting the weights of indicators based on the measured values ​​of parameters" also includes the following steps: The weights of the three adjusted indicators are normalized so that the sum of the weights of the three adjusted indicators is 100%.

6. The method for assessing the adaptability of submerged plants to water quality sediment according to claim 2, characterized in that, Calculating the utility value of the indicator includes the following steps: Calculate the utility value of the parameters of the indicator; Assign weights to the parameters; The utility value of the index is calculated based on the utility value of the parameters and the parameters themselves.

7. The method for assessing the adaptability of submerged plants to water quality sediment according to claim 6, characterized in that, Calculating the utility value of the parameters of the indicator includes the following steps: The formula for calculating the utility value of transparency is: , In the formula, The utility value of the transparency. The measured value of the transparency; The formula for calculating the effectiveness of the redox potential is as follows: , In the formula, The effective value of the redox potential is... The measured value of the redox potential is given. The formula for calculating the utility value of the biomass growth rate is: , In the formula, The utility value of the biomass growth rate. This refers to the measured value of the biomass growth rate; The formula for calculating the utility value of root vitality is: , In the formula, The utility value of the root vitality. The measured value of the root vitality; The formula for calculating the utility value of chlorophyll a is as follows: , In the formula, The utility value of chlorophyll a is given. The measured value of chlorophyll a is given.

8. The method for assessing the adaptability of submerged plants to aquatic sediment according to claim 2, characterized in that, The formula for calculating the fitness index is as follows: , In the formula, For adaptability index, The weights of water quality factors, The normalized value of the membership function for the water quality factor. The weights of the sediment factors, This represents the normalized value of the membership function for the sediment factor. The weights of plant factors, This represents the normalized value of the membership function for plant factors.

9. An ecological restoration decision-making method, characterized in that, Includes the following steps: Decision-making schemes are determined based on the adaptability index; The adaptability index is the adaptability index obtained by the method for evaluating the adaptability of submerged plant sediment in water quality according to any one of claims 1-8.

10. The ecological restoration decision-making method according to claim 9, characterized in that, "Determining a decision-making scheme based on the aforementioned adaptability index" includes the following steps: When the fitness index is greater than 0.8, direct planting is permitted; When the adaptability index is between 0.6 and 0.8, the plant is planted after environmental improvement; When the fitness index is less than 0.6, abandon planting or initiate an alternative program.

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