Repair method suitable for fish multi-nutritional-level habitat in water conservancy buffer area

Abstract

The invention discloses a water conservancy buffer fish multi-nutrition-level habitat restoration method, which comprises the following steps: S1, obtaining an ecological system structure of a water conservancy buffer, and determining representative species and ecological requirements of different nutrition-level fishes; s2, identifying habitat ranges matched with ecological requirements of fishes with different nutritional levels in the water conservancy buffer area; s3, constructing an ecological connectivity model of the multi-nutrition-level fish habitats, and quantifying connectivity indexes among the habitats; s4, determining a target habitat needing to be repaired and optimized according to connectivity indexes and ecological requirements of fishes of different nutritional levels; and S5, aiming at the target habitat, making a repair strategy, and constructing a repair effect evaluation system. Effective restoration of the fish habitat in the water conservancy buffer area and sustainable development of an ecological system are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of habitat restoration, and particularly to a method for restoring multi-trophic habitats of fish suitable for water conservancy buffer zones. Background Art

[0002] During the construction and operation of water conservancy projects, significant changes have occurred in the ecological environment of water conservancy buffer zones, having many adverse effects on the survival and reproduction of fish. The construction of water conservancy projects has changed the topography and geomorphology of water areas, destroyed the original hydrodynamic structure of water flows, resulting in changes in hydrological conditions such as water flow velocity and water depth, and reducing the suitable habitat space for fish. At the same time, changes in the chemical structure of water quality, such as problems of pollutant discharge and nutrient imbalance, have affected the food sources and breeding conditions of fish. In addition, the biological community structure and food web structure have also been disturbed, breaking the ecological relationships among fish. The combined action of these factors has caused a reduction in the fish population and a decrease in diversity. Therefore, it is necessary to restore the ecological environment of fish in water conservancy buffer zones, ensure the integrity of multi-trophic habitats of fish, and maintain the stability and health of the ecosystem.

[0003] Traditional fish habitat restoration techniques in water conservancy buffer zones mainly focus on the improvement of single factors. In terms of improving the habitat space, simple channel widening or deepening projects are often adopted. Although it can increase the activity space of fish to a certain extent, it does not fully consider the mutual relationships among hydrodynamic forces, water quality, and biological communities. Widening or deepening the channel will change the water flow velocity and direction, having a negative impact on fish that rely on specific water flow conditions, and it does not fundamentally solve the problems of food web structure imbalance and limited breeding conditions. In terms of improving food sources, traditional techniques simply put some feeds, and this method cannot establish a stable and sustainable food web. The excessive feeding of feeds also leads to water quality deterioration and further damages the fish habitat environment. In addition, when dealing with the problem of habitat connectivity, traditional restoration techniques often simply set some water passing channels, without fully considering the migration habits of fish and the impact of obstacles on migration, resulting in poor improvement effects of connectivity. Generally speaking, traditional technical solutions lack systematicness and comprehensiveness, cannot fully meet the ecological needs of fish at different trophic levels, and are difficult to effectively restore the fish habitat in water conservancy buffer zones and restore the ecosystem functions.

[0004] The existing technologies have made certain progress in the restoration of fish habitats in the water conservancy buffer zone, and pay more attention to the integrity of the ecosystem compared with traditional technologies. By constructing ecological slopes to improve the habitat environment, the ecological slopes can not only stabilize the riverbanks, but also provide certain habitats and breeding places for fish, and at the same time promote the growth of aquatic plants and microorganisms, optimizing the food web structure to a certain extent. Some technologies also adopt the method of ecological water replenishment to regulate the water volume and water quality of the water area, improving the living environment of fish. However, there are still some deficiencies in the existing technologies. On the one hand, the existing technologies have insufficient accuracy in matching the ecological needs of fish at different trophic levels. When determining the scope of habitat restoration, the differences in food sources, habitat spaces and breeding conditions of fish at different trophic levels are often not fully considered, resulting in weak pertinence of the restoration measures. On the other hand, the existing technologies lack in the quantitative evaluation of the restoration effect. Although some basic environmental indicators can be monitored, the quantitative evaluation of key indicators such as fish population dynamics and the restoration of ecosystem functions is not comprehensive and accurate enough, making it difficult to adjust the restoration strategy in a timely manner according to the evaluation results, affecting the continuous optimization and final effect of the restoration work.

[0005] Therefore, neither traditional technologies nor existing technologies can fully meet the needs of restoring multi-trophic fish habitats in the water conservancy buffer zone. Summary of the Invention

[0006] Based on the above content, a method for restoring multi-trophic fish habitats applicable to the water conservancy buffer zone in this application includes the following steps:

[0007] S1. Obtain the ecosystem structure of the water conservancy buffer zone, and determine the representative species and ecological needs of fish at different trophic levels;

[0008] S2. Identify the habitat ranges in the water conservancy buffer zone that match the ecological needs of fish at different trophic levels, and conduct preliminary classification according to the natural attributes and disturbance degrees of the habitats to obtain different types of habitats;

[0009] S3. Construct an ecological connectivity model for multi-trophic fish habitats, simulate the migration paths and diffusion capabilities of fish between different types of habitats, and quantify the connectivity indicators between habitats;

[0010] S4. According to the connectivity indicators and the ecological needs of fish at different trophic levels, determine the target habitats that need to be restored and optimized, and preferentially select the target habitat areas that have a key impact on the ecological system functions of multi-trophic fish and have poor connectivity;

[0011] S5. For the target habitats, formulate restoration strategies, construct a restoration effect evaluation system, and monitor in real time the population dynamics of multi-trophic fish, the changes in the habitat environment and the restoration of ecosystem functions during the restoration process, and dynamically adjust the restoration strategies according to the evaluation results.

[0012] Preferably, the ecosystem structure of the water conservancy buffer zone in S1 includes a water area topographic and geomorphic structure, a water flow dynamic structure, a water quality chemical structure, a biological community structure, and a food web structure formed by the interactions among various organisms; among them, the biological community structure consists of plankton, aquatic plants, benthic animals, and fish; by determining the representative species and ecological requirements of fish at different trophic levels through the obtained ecosystem structure, the ecological requirements include food sources, habitat spaces, and breeding conditions.

[0013] Preferably, in S2, when identifying the habitat range in the water conservancy buffer zone that matches the ecological requirements of fish at different trophic levels by constructing a comprehensive habitat matching model, specifically:

[0014] Obtain the demand weights of the i-th trophic level fish for food sources, habitat spaces, and breeding conditions, and the demand weights are W is 、W iq 、W if , where W is +W iq +W if = 1, calculate the habitat matching degree M ij of area j for the i-th trophic level fish, and the formula is: M ij = W is ×F js +W iq ×F jq +W if ×F jf , where F js is the food source satisfaction degree, F jq is the habitat space satisfaction degree, and F jf is the breeding condition satisfaction degree; by traversing each area of the water conservancy buffer zone, when M ij is greater than the set threshold T i , it is determined that this area is the habitat range that matches the ecological requirements of the i-th trophic level fish.

[0015] Preferably, the demand weights W is 、W iq 、W if of the i-th trophic level fish for food sources, habitat spaces, and breeding conditions in S2 are calculated through a comprehensive weight model, specifically:

[0016] Define the preference matrix of different growth stages of fish for each ecological requirement as where i a is different growth stages, and the growth stages include juvenile stage, adult stage, and breeding stage, and j a is ecological requirements, including food sources, habitat spaces, and breeding conditions; calculate the comprehensive preference value The formula is: Where is the resource abundance correction coefficient vector of the water conservancy buffer zone. The larger the value, the richer the resources required for ecological needs or the better the conditions. The larger the value of

[0017] the higher the preference degree of the growth stage for the corresponding ecological needs. The demand weights of food sources, habitat spaces, and breeding conditions are obtained through normalization. The formula is:

[0018]

[0019] Among them, C1 is the comprehensive preference value of food sources during the growth process of fish, C2 is the comprehensive preference value of habitat spaces during the growth process of fish, and C3 is the comprehensive preference value of breeding conditions during the growth process of fish.

[0020] Preferably, the satisfaction degrees F js , F jq , F jf of food sources, habitat spaces, and breeding conditions in S2 are calculated as follows:

[0021] The food source satisfaction degree is calculated by obtaining the biomass and nutritional components of various food resources in the area to calculate the food source satisfaction degree F js . The formula is: Where P ik is the intake preference coefficient of the i-th trophic level fish for the k-th type of food, B jk is the biomass of the k-th type of food in the j-th area, N jk is the comprehensive score of the k-th type of nutritional component in the j-th area, and max(B k ) and max(N k ) are the maximum biomass and the highest nutritional component score of the k-th type of food in the entire water conservancy buffer zone respectively;

[0022] The habitat space satisfaction degree is calculated by obtaining the water depth suitability S Dj and the water flow velocity S Vj . The formula is: F jq =α q ×S Dj +β q ×S Vj , where α q and β q are the corresponding weight coefficients; the calculation formula of the water depth suitability S Dj is: Where D j is the water depth of the j-th area, and the suitable water depth range is [D min , D max ; the water flow velocity SVj The calculation formula is as follows: Where V j is the water flow velocity in the j-th area, and the suitable water flow velocity range is [V min , V max ;

[0023] The satisfaction degree of reproduction conditions is calculated by obtaining water temperature, water flow stability and the suitability of reproduction substrates. The formula is as follows: Where T j is the water temperature in the j-th area, T opt is the optimal water temperature for fish reproduction, R j is the water flow velocity change rate, Q j is the suitability of reproduction substrates, and ω, μ, ν are the corresponding weight coefficients.

[0024] Preferably, in the S3, an ecological connectivity model of a multi-trophic fish habitat is constructed to simulate the migration paths and diffusion capabilities of fish between different habitats and quantify the connectivity indicators between habitats. Specifically:

[0025] Obtain the distances, water flow conditions, and obstacle distributions between habitats, and construct a habitat connectivity model. The formula is as follows: is the straight-line distance between the m r -th habitat and the n r -th habitat, is the hindrance coefficient of water flow to fish migration, is the obstacle influence coefficient, and the connectivity index The larger the value, the better the connectivity between the two habitats.

[0026] Preferably, in the S4, the target habitats that need to be repaired and optimized are determined according to the connectivity indicators and the ecological requirements of fish at different trophic levels, and are determined by constructing a habitat repair priority index. Specifically:

[0027] Obtain the satisfaction degrees F js , F jq , F jf of the food source, habitat space, and reproduction conditions of the habitat, and the connectivity index between habitats to construct the repair priority index P j of habitat j. The formula is as follows: Where h is the number of habitats that have a connectivity relationship with habitat j. When P j > T S , it is determined that the habitat j is the target habitat that needs to be repaired and optimized, and T S is the repair priority threshold.

[0028] Preferably, the formulation of the restoration strategy in S5 includes, but is not limited to, reshaping the terrain and landforms, creating diverse water flow conditions and habitat microenvironments, optimizing the food web structure by introducing suitable aquatic plants and microbial communities, establishing ecological corridors to restore natural river channels, and enhancing the connectivity of habitat connections.

[0029] Preferably, in S5, a restoration effect evaluation system is constructed through a comprehensive evaluation index, specifically:

[0030] Obtain the habitat population change index P d , the environmental comprehensive change index E c and the material cycle efficiency index M r , calculate the comprehensive evaluation index R, and the formula is: R = α×P d +β×(1 - E c ) + γ×M r , where α, β, and γ are the corresponding weight coefficients, set different time thresholds R(t) according to different restoration stages. When R < R(t), analyze each sub - index. If P d is low, adjust the food web optimization strategy, increase or replace the types of aquatic organisms released; if E c is high, improve the habitat environment and adjust the water flow conditions to improve the dissolved oxygen content; if M r is low, optimize the ecosystem structure to achieve dynamic adjustment of the restoration strategy according to the evaluation results.

[0031] Preferably, the calculation of the habitat population change index P d , the environmental comprehensive change index E c and the material cycle efficiency index M r is specifically as follows:

[0032] The population change index P d is calculated by obtaining the species, quantity, and distribution information of fish at different trophic levels. The formula is: N l0 is the individual quantity of the l - th trophic level fish before restoration, N lt is the quantity at the t - time point during the restoration process, and m is the total number of trophic level fish species monitored;

[0033] The environmental comprehensive change index E c is calculated by obtaining key environmental factors such as water temperature, dissolved oxygen content, and pH value. The formula is: Among them, n s represents the total number of environmental factors participating in the evaluation, w q is the weight of the q - th environmental factor, X tq is the actual measured value of the q - th environmental factor at the t - time point during the restoration process; X0q is the ideal value of the q-th environmental factor, E c The smaller the value, the closer the habitat environment is to the ideal state;

[0034] Material cycle efficiency index M r It is calculated by obtaining the input and output amounts of nitrogen and phosphorus nutrients in the water body and the content change of nutrients in the sediment. The formula is: where I is the input amount of nutrients per unit time, O is the output amount, S is the net accumulation amount of nutrients in the sediment, and M r The closer it is to 1, the better the material cycle function of the ecosystem is restored.

[0035] Compared with the prior art, the technical solution of the present application has the following technical effects:

[0036] The present invention obtains the ecological system structure of the water conservancy buffer zone, clarifies the representative species and ecological requirements of fish at different trophic levels, including food sources, habitat space, and breeding conditions, uses the constructed comprehensive habitat matching model to calculate the habitat matching degree between the region and fish at different trophic levels, identifies the habitat range that matches the ecological requirements of fish at each trophic level, calculates the demand weight through the comprehensive weight model, makes the matching result more scientific and reasonable, improves the suitability of the habitat for fish, creates good conditions for the survival and reproduction of fish, and helps the recovery and growth of fish populations.

[0037] The present invention constructs an ecological connectivity model for multi-trophic fish habitats. By obtaining the distance, water flow conditions, and obstacle distribution information between habitats, a habitat connectivity model is constructed to quantify the connectivity index between habitats, enabling people to clearly understand the degree of connection tightness between different habitats, providing a strong basis for optimizing the habitat ecological network. For example, for habitats with a low connectivity index, targeted measures such as establishing ecological corridors and removing obstacles can be taken to enhance the connectivity between habitats and promote the migration and diffusion of fish between different habitats. Good ecological connectivity helps fish find more suitable living environments, obtain food and breeding places, maintain gene exchange in fish populations, and is of great significance for protecting fish biodiversity, making the fish habitats in the water conservancy buffer zone form an interconnected and stable ecological network.

[0038] Based on the connectivity index and the ecological requirements of fish at different trophic levels, the present invention scientifically determines the target habitats that need to be repaired and optimized by constructing a habitat restoration priority index, preferentially selects areas that have a key impact on the ecological system function of multi-trophic fish and have poor connectivity for restoration, avoids blind restoration, focuses resources on solving key problems, and significantly improves the restoration efficiency.

[0039] The present invention constructs a complete restoration effect evaluation system. By obtaining key indicators such as the habitat population change index, the environmental comprehensive change index and the material circulation efficiency index, the comprehensive evaluation index is calculated, and the population dynamics of multi-trophic level fish, habitat environmental changes and the recovery of ecosystem functions during the restoration process are monitored in real time. The corresponding time thresholds are set according to different restoration stages. When the comprehensive evaluation index does not meet the standard, the sub-indices can be quickly analyzed and the restoration strategy can be adjusted in a targeted manner.

[0040] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application so that it can be implemented in accordance with the contents of the specification, and to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following is a detailed description of the preferred embodiments of the present application in conjunction with the accompanying drawings as follows.

[0041] Based on the detailed description of the specific embodiments of the present application in combination with the accompanying drawings below, those skilled in the art will become more aware of the above and other objects, advantages and features of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings without creative work. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, each element or part is not necessarily drawn according to the actual scale.

[0043] Figure 1 A flowchart of a multi-trophic level habitat restoration method for fish in hydraulic buffer zones;

[0044] Figure 2 This is a structural diagram of the multi-trophic level habitat model for fish in the experimental water buffer zone;

[0045] Figure 3 This is a comparison chart of the number of fish in the experimental area and the control area at a certain time. DETAILED DESCRIPTION

[0046] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are some, but not all, of the embodiments of this application. In the following description, specific details such as specific configurations and components are provided only to assist in a comprehensive understanding of the embodiments of this application. Therefore, those skilled in the art should clearly understand that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. Additionally, descriptions of known functions and structures are omitted in the embodiments for the sake of clarity and conciseness.

[0047] It should be understood that the phrase "one embodiment" or "this embodiment" mentioned throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, the phrase "one embodiment" or "this embodiment" that appears throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in one or more embodiments in any suitable manner.

[0048] In addition, this application may repeat reference numerals and / or letters in different examples. This repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or arrangements discussed.

[0049] The term "and / or" in this document is merely a description of the associated relationship of the associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, B exists alone, and both A and B exist simultaneously. The term " / and" in this document is a description of another associated object relationship, indicating that two relationships can exist. For example, A / and B can represent: A exists alone, and both A and B exist. Additionally, the character " / " in this document generally indicates that the associated objects before and after are in an "or" relationship.

[0050] The term "at least one" in this document is merely a description of the associated relationship of the associated objects, indicating that three relationships can exist. For example, at least one of A and B can represent: A exists alone, both A and B exist simultaneously, and B exists alone.

[0051] It should also be noted that in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprise," "include," or any other variant thereof are intended to cover non-exclusive inclusion.

[0052] Embodiment 1

[0053] This embodiment mainly describes a method for restoring multi-trophic habitats of fish in a water conservancy buffer zone, such as Figure 1 shown, which includes the following steps:

[0054] S1. Obtain the ecosystem structure of the water conservancy buffer zone, and determine the representative species and ecological requirements of fish at different trophic levels;

[0055] S2. Identify the habitat ranges in the water conservancy buffer zone that match the ecological requirements of fish at different trophic levels, conduct a preliminary classification according to the natural attributes and disturbance levels of the habitats, and obtain different types of habitats;

[0056] S3. Construct an ecological connectivity model for multi-trophic fish habitats, simulate the migration paths and diffusion capabilities of fish between different types of habitats, and quantify the connectivity indicators between habitats;

[0057] S4. According to the connectivity indicators and the ecological requirements of fish at different trophic levels, determine the target habitats that need to be restored and optimized, and preferentially select the target habitat areas that have a key impact on the ecological functions of the multi-trophic fish ecosystem and have poor connectivity;

[0058] S5. For the target habitats, formulate restoration strategies, construct an evaluation system for restoration effects, monitor the population dynamics of multi-trophic fish, the changes in habitat environment, and the restoration of ecosystem functions during the restoration process in real time, and dynamically adjust the restoration strategies according to the evaluation results.

[0059] Furthermore, the ecosystem structure of the water conservancy buffer zone in S1 includes the water area topographic and geomorphic structure, the water flow dynamic structure, the water quality chemical structure, the biological community structure, and the food web structure formed by the interactions between various organisms; among them, the biological community structure consists of plankton, aquatic plants, benthic animals, and fish; determine the representative species and ecological requirements of fish at different trophic levels through the obtained ecosystem structure, and the ecological requirements include food sources, habitat spaces, and breeding conditions.

[0060] Furthermore, in S2, when identifying the habitat ranges in the water conservancy buffer zone that match the ecological requirements of fish at different trophic levels by constructing a habitat comprehensive matching model, specifically:

[0061] Obtain the demand weights of the i-th trophic level fish for food sources, habitat spaces, and breeding conditions, and the demand weights are W is 、W iq 、W if , where W is +W iq +W if =1, calculate the habitat matching degree M ij of area j for the i-th trophic level fish, and the formula is: M ij =Wis ×F js +W iq ×F jq +W if ×F jf , where F js is the satisfaction degree of food source, F jq is the satisfaction degree of habitat space, F jf is the satisfaction degree of breeding conditions; by traversing each area of the water conservancy buffer zone, when M ij is greater than the set threshold T i , it is determined that this area is the habitat range matching the ecological requirements of the fish of the i-th trophic level.

[0062] Furthermore, the demand weights W is , W iq , W if of the fish of the i-th trophic level for food source, habitat space, and breeding conditions in S2 are calculated through a comprehensive weight model, specifically:

[0063] Define the preference matrix of different growth stages of fish for each ecological requirement as where i a is different growth stages, and the growth stages include juvenile stage, adult stage, and breeding stage, and j a is ecological requirements, including food source, habitat space, and breeding conditions; calculate the comprehensive preference value The formula is: where is the resource abundance correction coefficient vector of the water conservancy buffer zone, and the larger the value, the richer the resources or the better the conditions of the ecological requirements, The larger the value of

[0064] means the higher the preference degree of the growth stage for the corresponding ecological requirement;

[0065]

[0066] where C1 is the comprehensive preference value of food source during the growth process of fish, C2 is the comprehensive preference value of habitat space during the growth process of fish, and C3 is the comprehensive preference value of breeding conditions during the growth process of fish.

[0067] Furthermore, the calculation of the satisfaction degrees F js , F jq , F jf of food source, habitat space, and breeding conditions in S2 is specifically:

[0068] The food source satisfaction degree is calculated by obtaining the biomass and nutritional components of various food resources in the area to calculate the food source satisfaction degree Fjs , the formula is: where P ik is the intake preference coefficient of the fish of the i-th trophic level for the k-th type of food, B jk is the biomass of the k-th type of food in the j-th area, N jk is the comprehensive score of the k-th type of nutrient component in the j-th area, max(B k ) and max(N k ) are respectively the maximum biomass and the highest nutrient component score of the k-th type of food in the entire water conservancy buffer zone;

[0069] The habitat space satisfaction degree is calculated by obtaining the water depth suitability S Dj and the water flow velocity S Vj , and the formula is: F jq =α q ×S Dj +β q ×S Vj , where α q and β q are the corresponding weight coefficients; the calculation formula of the water depth suitability S Dj is: where D j is the water depth of the j-th area, and the suitable water depth range is [D min , D max ; the calculation formula of the water flow velocity S Vj is: where V j is the water flow velocity of the j-th area, and the suitable water flow velocity range is [V min , V max ;

[0070] The breeding condition satisfaction degree is calculated by obtaining the water temperature, water flow stability and breeding substrate suitability, and the formula is: where T j is the water temperature of the j-th area, T opt is the optimal water temperature for fish breeding, R j is the water flow velocity change rate, Q j is the breeding substrate suitability, and ω, μ, v are the corresponding weight coefficients.

[0071] Furthermore, in the above-mentioned S3, an ecological connectivity model of the multi-trophic fish habitat is constructed to simulate the migration paths and diffusion capabilities of fish between different habitats, and quantify the connectivity indicators between each habitat. Specifically:

[0072] Obtain the distances, water flow conditions, and obstacle distributions between habitats, and construct a habitat connectivity model. The formula is: is the straight-line distance between the m r th habitat and the n r th habitat. is the hindrance coefficient of water flow to fish migration. is the obstacle influence coefficient. The larger the connectivity index , the better the connectivity between the two habitats.

[0073] Furthermore, in the above S4, the target habitats that need to be restored and optimized are determined according to the connectivity index and the ecological requirements of fish at different trophic levels, and are determined by constructing a habitat restoration priority index, specifically:

[0074] Obtain the satisfaction degrees F js , F jq , F jf of the food source, habitat space, and breeding conditions of the habitat, and the connectivity index between habitats Construct the restoration priority index P j of habitat j, and the formula is: where h is the number of habitats that have a connectivity relationship with habitat j. When P j >T s , it is determined that the habitat j is the target habitat that needs to be restored and optimized, and T s is the restoration priority threshold.

[0075] Furthermore, the formulation of the restoration strategy in the above S5 includes but is not limited to reshaping the terrain and landform, creating diverse water flow conditions and habitat microenvironments, optimizing the food web structure by introducing suitable aquatic plants and microbial communities, and establishing ecological corridors to restore natural river channels and enhance the connectivity of habitat connections.

[0076] Furthermore, in the above S5, a restoration effect evaluation system is constructed through a comprehensive evaluation index, specifically:

[0077] Obtain the habitat population change index P d , the environmental comprehensive change index E c , and the material cycle efficiency index M r , and calculate the comprehensive evaluation index R. The formula is: R = α×P d +β×(1 - E c )+γ×M r , where α, β, and γ are the corresponding weight coefficients. Set different time thresholds R(t) according to different restoration stages. When R < R(t), analyze each sub-index. If P d is low, adjust the food web optimization strategy and increase or replace the types of aquatic organisms released; if E c is high, improve the habitat environment and adjust the water flow conditions to improve the dissolved oxygen content; if M rLower, optimize the ecosystem structure, and realize dynamic adjustment of the restoration strategy according to the evaluation results.

[0078] Furthermore, the habitat population change index P d , the environmental comprehensive change index E c and the material cycle efficiency index M r are calculated specifically as follows:

[0079] The population change index P d is calculated by obtaining the species, quantity, and distribution information of fish at different trophic levels. The formula is: N l0 is the individual quantity of the l-th trophic level fish before restoration, N lt is the quantity at the t-th time point during the restoration process, and m is the total number of monitored trophic level fish species;

[0080] The environmental comprehensive change index E c is calculated by obtaining key environmental factors such as water temperature, dissolved oxygen content, and acidity and alkalinity. The formula is: Among them, n s represents the total number of environmental factors participating in the evaluation, w q is the weight of the q-th environmental factor, X tq is the actual measured value of the q-th environmental factor at the t-th time point during the restoration process; X 0q is the ideal value of the q-th environmental factor. The smaller the E c value, the closer the habitat environment is to the ideal state;

[0081] The material cycle efficiency index M r is calculated by obtaining the input and output amounts of nitrogen and phosphorus nutrients in the water body and the change in the nutrient content in the sediment. The formula is: Among them, I is the input amount of nutrients per unit time, O is the output amount, S is the net accumulation amount of nutrients in the sediment, and M r the closer it is to 1, the better the material cycle function of the ecosystem is restored.

[0082] This embodiment details that this application determines a suitable habitat range by matching the ecological needs of fish at different trophic levels, quantifies the connectivity index, optimizes the habitat ecological network, scientifically selects the restoration target, and improves the restoration efficiency and effect; by constructing an evaluation system, it monitors in real time and dynamically adjusts the restoration strategy to comprehensively guarantee the restoration of the fish habitat in the water conservancy buffer zone and promote the restoration of the fish population and the stable and healthy development of the ecosystem.

[0083] Based on Embodiment 1, this embodiment details obtaining the distances, water flow conditions, and obstacle distributions between habitats in S3 and constructing a habitat connectivity model as follows;

[0084] Obtain the distances between habitats, water flow conditions, and obstacle distributions, and construct a habitat connectivity model. The formula is: is the straight-line distance between the m r th habitat and the n r th habitat, is the hindrance coefficient of water flow to fish migration, is the obstacle influence coefficient, and the connectivity index The larger it is, the better the connectivity between the two habitats;

[0085] To determine the hindrance coefficient of water flow to fish migration By obtaining the water flow velocity in the jth area and the optimal water flow velocity V opt for fish to migrate appropriately, calculate using the formula: where V j is the water flow velocity in the jth area, V opt is the optimal water flow velocity for fish to migrate appropriately, |V j -V opt | is used to measure the difference between the actual water flow velocity and the optimal velocity. The greater the difference, the greater the hindrance coefficient; α k and β k are the corresponding adjustment coefficients to adjust the influence weights of different factors on the hindrance coefficient; ΔV j is the fluctuation amplitude of the water flow velocity. The greater the fluctuation, the stronger the hindrance effect; γ k is the correction coefficient, with a value range between 0 and 1, adjusted according to the swimming ability and adaptation characteristics of different fish species to more accurately reflect the hindrance degree of water flow to the migration of specific fish species;

[0086] The obstacle influence coefficient is constructed by comprehensively considering the type, quantity, distribution density of obstacles, and the degree of blocking of fish migration routes. The formula is: where n o represents the total number of obstacles between habitats, T i is the obstacle type influence factor (different types of obstacles such as dams and bridge piers are assigned different values, with a value range of 0 - 1. The T i value of obstacles that completely block fish migration approaches 1, and the T i value of obstacles that have less impact on fish migration approaches 0), D i is the obstacle distribution density (the number of obstacles per unit area), L i is the proportion of the length of the obstacle blocking the fish migration route to the total migration route length, S i$S_i$ is the surface area of the $i$-th obstacle. By calculating and integrating various factors, the obstacle influence coefficient is obtained to accurately measure the impact of obstacles on the migration of fish between different habitats.

[0087] This implementation details the construction of a habitat connectivity index formula that includes factors such as the distance between habitats, water flow conditions, and obstacle distribution. The connectivity index between habitats is quantified, clearly understanding the difficulty of fish migration between different habitats, providing a scientific basis for subsequent targeted optimization of habitat connectivity. Through quantitative analysis, areas with poor connectivity can be efficiently identified, and then reasonable measures can be taken to effectively promote the migration and diffusion of fish between different habitats.

[0088] Based on Example 1, this example details the fish habitat restoration experiment in the water conservancy buffer zone of this application, specifically as follows:

[0089] As Figure 2 shown, in a certain water conservancy buffer zone, due to long-term human activities and water conservancy project construction, the fish habitat has been damaged, and the fish population quantity and diversity have decreased significantly. To improve this situation, this comparative experiment is carried out. In the experiment, two areas with similar areas and similar degrees of ecological environment damage in the water conservancy buffer zone are selected and marked as the experimental area (using the technical solution of this application) and the control area (using the existing technology) respectively. Both the experimental area and the control area include the river and shallow water area environment of the water conservancy buffer zone, and the intensity of surrounding human activities is quite the same. Before the experiment, the basic ecological data of the two areas are measured in detail, including but not limited to topography, water flow velocity, water temperature, water quality, and the initial quantity and distribution of various organisms, as shown in the following table:

[0090] Measurement items Experimental area Control area <![CDATA[Water area (km 2 )]]> 2.35 2.42 Average water depth (m) 3.25 3.18 Average water flow velocity (m / s) 0.42 0.45 Water temperature (°C) 18.52 18.65 Dissolved oxygen content (mg / L) 6.25 6.18 <![CDATA[Plankton biomass (g / m 3 )]]> 15.36 14.98 <![CDATA[Benthic animal biomass (g / m 2 )]]> 35.68 34.87 Number of fish species 12 11 Total number of fish (tails) 567.32 534.45

[0091] According to the representative species of fish at different trophic levels in the experimental area, their ecological requirements are determined. Taking crucian carp (primary consumer), perch (mid-level consumer), and catfish (high-level consumer) as research objects, through consulting literature and on-site observation, the demand weights for food sources, habitat space, and breeding conditions are obtained, and using the habitat comprehensive matching model, the habitat matching degree $M_j$ of the area for fish at different trophic levels is calculated. ij , and the demand weights $W$ of crucian carp for food sources, habitat space, and breeding conditions are obtained. is $= 0.42$, $W$ iq $= 0.35$, $W$ if $= 0.23$, and the habitat matching degree $M_j$ of area $j$ for crucian carp is calculated, where the food source satisfaction degree $F$ 1j jsBy calculating the biomass and nutritional components of food resources such as plankton and aquatic insects in the area, it is calculated that within the experimental area, 5 habitat ranges matching the ecological needs of crucian carp, 3 habitat ranges matching the ecological needs of perch, and 2 habitat ranges matching the ecological needs of catfish are determined.

[0092] Taking the habitat ranges A and B of crucian carp as an example, obtain the distance between habitats, water flow conditions, and obstacle distribution information, and construct a habitat connectivity model. The straight-line distance between habitat A and habitat B is about 1.25 km. After calculation, the hindrance coefficient of water flow to fish migration obstacle influence coefficient then

[0093] For the hindrance coefficient of fish migration measured by ADCP is 0.38 m / s, V opt is the optimal water flow speed suitable for crucian carp migration, determined to be 0.45 m / s according to relevant research and experimental measurements. α k = 0.6, β k = 0.4 are adjustment coefficients, determined according to the water flow characteristics and fish migration habits in the experimental area; ΔV j is the fluctuation range of the water flow speed, obtained by continuously monitoring the water flow speed over a period of time and calculating the standard deviation to be 0.05 m / s; γ k = 0.8 is a correction coefficient, determined according to the swimming ability and adaptation characteristics of crucian carp for calculation

[0094] For the obstacle influence coefficient Between habitats A and B, there are 2 obstacles, numbered O1 and O2. O1 is a small bridge pier, with T1 = 0.8 (since the bridge pier has a large hindrance to fish migration, a relatively high value is assigned), the distribution density D1 = 0.002 (calculated according to the area and quantity of the area where the bridge pier is located), the proportion L1 of the length of the fish migration route blocked by the bridge pier to the total migration route length is 0.3, and the surface area S1 = 20 m 2 ; O2 is an underwater reef group, T2 = 0.6. The reef group has a certain hindrance to fish migration, but less than that of the bridge pier, D2 = 0.003, L2 = 0.2, S2 = 15 mm 2 , after calculation,

[0095] According to the same method, calculate the connectivity index between all habitats, and comprehensively analyze the migration routes and diffusion capabilities of fish between different habitats.

[0096] According to the connectivity index and the ecological requirements of fish at different trophic levels, a habitat restoration priority index is constructed to determine the target habitats that need to be restored and optimized. Taking the habitats numbered H1, H2, and H3 as examples for implementing restoration strategies on the target habitats, they have connectivity relationships with other habitats and involve the survival needs of fish at different trophic levels such as crucian carp, perch, and catfish. When calculating the restoration priority index of these habitats, the food source satisfaction degree F js , the habitat space satisfaction degree F jq , and the breeding condition satisfaction degree F jf are all calculated in detail according to the above method. Taking the H3 habitat as an example, the food source satisfaction degree F 3s of the H3 habitat for crucian carp is calculated by detailed statistics of the biomass and nutrient components of various food resources such as plankton and aquatic insects in this area, and the calculated value is 0.55; the habitat space satisfaction degree F 3q is calculated by obtaining the water depth suitability S D3 and the water flow velocity S V3 . D3 is the water depth of the H3 area, which is measured to be 3.5 m, and the suitable water depth range is [3, 4] m. The calculated S D3 ≈0.73. V3 is the water flow velocity of the H3 area, and the measured value is 0.4 m / s. The suitable water flow velocity range is [0.3, 0.5] m / s. The calculated S V3 ≈0.62, then F 3q = 0.68, α q = 0.6, β q = 0.4; the breeding condition satisfaction degree F 3f is calculated by obtaining the water temperature, water flow stability, and breeding substrate suitability. Let ω = 0.4, μ = 0.3, v = 0.3. T3 is the water temperature of the H3 area, and the measured value is 19 °C. T opt is the optimal water temperature for fish breeding, which is set to 20 °C. R3 is the water flow velocity change rate, which is monitored to be 0.1 m / s. Q j is the breeding substrate suitability, which is evaluated to be 0.8, then F 3f ≈0.74; the number of habitats with connectivity relationships with the H3 habitat is h = 4, and its connectivity index has been calculated in the previous text. The 4 connectivity indices are C m1 = 1.2, C m2 = 1.1, C m3 = 1.3, C m4 = 1.0, then P3≈0.012. Similarly, calculate the restoration priority indices of the H1 and H2 habitats. P1 = 0.015, P2 = 0.018. The restoration priority threshold is set as T S = 0.01. Since both P1 and P2 are greater than T S, so it is determined that H1 and H2 are the target habitats that need to be repaired and optimized.

[0097] Implement repair strategies for the identified target habitats H1 and H2: including reshaping the terrain and landform. In the shoal area of H1 habitat, it is planned to dig a deep trench with a length of 200m, a width of 30m, and a depth of 1.5m. After the excavation, the average water depth in this area has increased from the original 2.2m to 2.8m, and the range of water depth change has increased, providing a more diverse habitat space for fish with different habits. In H2 habitat, some areas with relatively high terrain are leveled, and the height is reduced by about 0.8m, expanding the shoal area by about 500m 2 , creating more favorable conditions for the growth of aquatic plants and the habitation of benthic animals.

[0098] Create diverse water flow conditions and microhabitats: In the water flow channels of H1 habitat, 3 groups of diversion dams are set up, each group of diversion dams is 15m long and 0.5m high. By adjusting the angle and position of the diversion dams, the water flow speed and direction are changed. After measurement, after setting up the diversion dams, the water flow speed in this area has changed significantly at different positions. The water flow speed in some areas has decreased from the original 0.4m / s to 0.25m / s, forming a slow-flow area; while in other areas, the water flow speed has increased to 0.55m / s, forming a rapid-flow area. This diverse water flow condition provides a suitable habitat environment for fish with different swimming abilities and habits. In H2 habitat, 500 artificial fish nests with a diameter of 0.8m are put in. The fish nests are made of environmentally friendly materials and simulate the natural rock and branch structures, providing a place for fish to lay eggs and avoid natural enemies.

[0099] Introduce suitable aquatic plants and microbial communities to optimize the food web structure: In H1 and H2 habitats, aquatic plants such as water hyacinths and duckweeds are planted respectively, and screened microbial agents are put into the water body, with a dosage of 50g per cubic meter of water body. These microorganisms can decompose organic substances in the water body, increase the dissolved oxygen in the water body, promote the growth of aquatic plants, and provide a more abundant food source for fish.

[0100] Build an ecological corridor to enhance the connectivity of habitat connection: Between H1 and H2 habitats, a small abandoned dam with a length of 10m and a height of 2m is demolished. After the demolition, an ecological corridor with a width of 5m and a length of 80m is built. The bottom of the corridor is paved with gravel and sand, providing a convenient passage for fish migration. At the same time, willow trees and other trees are planted on both sides of the corridor, playing a role of shading and protection, and further enhancing the connectivity between habitats.

[0101] Monitoring and evaluation: Establish a restoration effect evaluation system to monitor in real time the population dynamics of multi-trophic fish, the changes in habitat environment, and the restoration of ecosystem functions during the restoration process. Population change index monitoring: Regularly (once a month) monitor the species, quantity, and distribution information of fish at different trophic levels in the experimental area. Taking crucian carp as an example, before restoration, the number of crucian carp in the experimental area was 120. During the restoration process, the number increased to 135 at the 3rd month and reached 152 at the 6th month. Calculate that the population change index of crucian carp was approximately 0.125 at the 3rd month and approximately 0.27 at the 6th month. Calculate and monitor the population change indices of other trophic-level fish such as perch and catfish in the same way.

[0102] Monitor by obtaining key environmental factors such as water temperature, dissolved oxygen content, and pH. Before restoration, water temperature X 01 = 18.5 °C, dissolved oxygen content X 02 = 6.2 mg / L, pH X 03 = 7.3; After 6 months of restoration, the water temperature X 11 in habitat H1 = 19.2 °C, dissolved oxygen content X 12 = 6.8 mg / L, pH X 13 = 7.4. The comprehensive environmental change index of habitat H1 after 6 months of restoration is approximately 0.05. Similarly, regularly calculate and analyze the comprehensive environmental change indices of habitat H5 and other monitoring points.

[0103] Monitor the input and output amounts of nitrogen and phosphorus nutrients in the water body of habitat H1 and the change in the nutrient content in the sediment. Before restoration, the input amount I0 of nutrients per unit time (per month) = 150.12 kg, the output amount O0 = 102.36 kg, and the net accumulation amount S0 of nutrients in the sediment = 21.26 kg. Then the material cycle efficiency index is approximately 0.8; After 12 months of restoration, the input amount I1 of nutrients per unit time in habitat H1 = 140.65 kg, the output amount O1 = 129.65 kg, and the net accumulation amount S1 of nutrients in the sediment = 25.65 kg. Calculate that the material cycle efficiency index is approximately ≈0.96; Continuously monitor and evaluate the material cycle efficiency indices of habitat H2 and the entire experimental area.

[0104] The control area adopts existing technologies, mainly conducts simple river channel cleaning, removes some large garbage and obstacles; puts a certain amount of artificial feed to supplement the fish food source; plants single aquatic plants in some areas to improve water quality and provide habitats.

[0105] Through this comparative experiment, as Figure 3As shown, through the comparison of fish numbers, it can be intuitively seen that the technical solution of this application has significant advantages in the restoration of multi-trophic habitats for fish in the water conservancy buffer zone. Compared with the prior art, the technical solution of this application can more effectively promote the growth of fish population numbers and the restoration of species diversity, significantly improve the habitat environment, and enhance the material cycle efficiency of the ecosystem.

[0106] This embodiment details the comparative test between this application and the prior art in the fish habitat of the water conservancy buffer zone, verifying that this application has scientific and effective technical means, has important practical application value and promotion significance, and makes greater contributions to the protection and restoration of the aquatic ecosystem.

[0107] The above are only the preferred embodiments of the present invention, and it does not thereby limit the protection scope of the present invention. For those skilled in the art, the present invention can have various changes and modifications; within the spirit and principle of the present invention, any changes, modifications, substitutions, integrations, and parameter changes made to these embodiments through conventional substitutions or capable of achieving the same functions without departing from the principle and spirit of the present invention fall within the protection scope of the present invention.

Claims

1. A method for restoring multi-trophic habitats of fish suitable for water conservancy buffer zones, characterized in that, Including: S1. Obtain the ecosystem structure of the water conservancy buffer zone, and determine the representative species and ecological requirements of fish at different trophic levels; S2. Identify the habitat ranges in the water conservancy buffer zone that match the ecological requirements of fish at different trophic levels, conduct a preliminary classification based on the natural attributes and disturbance degrees of the habitats, and obtain different types of habitats; S3. Construct an ecological connectivity model for multi-trophic fish habitats, simulate the migration paths and diffusion abilities of fish between different types of habitats, and quantify the connectivity indicators between each habitat; S4. According to the connectivity indicators and the ecological requirements of fish at different trophic levels, determine the target habitats that need to be repaired and optimized, and preferentially select the target habitat areas that have a key impact on the ecological functions of the multi-trophic fish ecosystem and have poor connectivity; S5. For the target habitats, formulate repair strategies, construct a repair effect evaluation system, monitor in real time the population dynamics of multi-trophic fish, the changes in the habitat environment, and the restoration of ecosystem functions during the repair process, and dynamically adjust the repair strategies according to the evaluation results.

2. The method for restoring a multi-trophic fish habitat in a water conservancy buffer zone according to claim 1, characterized in that In S1, the ecosystem structure of the water conservancy buffer zone includes the water area topographic and geomorphic structure, the water flow dynamic structure, the water quality chemical structure, the biological community structure, and the food web structure formed by the interactions between various organisms; among them, the biological community structure consists of plankton, aquatic plants, benthic animals, and fish; determine the representative species and ecological requirements of fish at different trophic levels through the obtained ecosystem structure, and the ecological requirements include food sources, habitat spaces, and breeding conditions.

3. A method for restoring multi-trophic habitats of fish in a water conservancy buffer zone according to claim 1, characterized in that, In S2, when identifying the habitat ranges in the water conservancy buffer zone that match the ecological requirements of fish at different trophic levels by constructing a habitat comprehensive matching model, specifically: Obtain the demand weights of the fish at the i-th trophic level for food sources, habitat space, and breeding conditions, and the demand weights are W is , W iq , W if , where W is + W iq + W if = 1. Calculate the habitat matching degree M ij of region j for the fish at the i-th trophic level. The formula is: M ij = W is × F js + W iq × F jq + W if × F jf , where F js is the food source satisfaction degree, F jq is the habitat space satisfaction degree, and F jf is the breeding condition satisfaction degree; by traversing each region of the water conservancy buffer zone, when M ij is greater than the set threshold T i , determine that this region is the habitat range that matches the ecological needs of the fish at the i-th trophic level.

4. A method for restoring a multi-trophic fish habitat applicable to a water conservancy buffer zone according to claim 3, characterized in that The demand weights W is 、W iq 、W if of the i-th trophic level fish for food sources, habitat space, and breeding conditions in S2 are calculated through a comprehensive weight model, specifically as follows: Define the preference matrix of different growth stages of fish for various ecological requirements as where i a represents different growth stages, including juvenile stage, adult stage and breeding stage, and j a represents ecological requirements, including food source, habitat space and breeding conditions; Calculate the comprehensive preference value The formula is as follows: Where is the resource abundance correction coefficient vector of the water conservancy buffer zone. The larger the value, the richer the resources required for ecological needs or the better the conditions. The larger the value of, the higher the preference degree of the growth stage for the corresponding ecological needs. Obtain the demand weights of food sources, habitat spaces, and breeding conditions through normalization processing, and the formula is: Among them, C1 is the comprehensive preference value of food sources during the growth process of fish, C2 is the comprehensive preference value of habitat spaces during the growth process of fish, and C3 is the comprehensive preference value of breeding conditions during the growth process of fish.

5. A method for restoring multi-trophic habitats of fish in a water conservancy buffer zone according to claim 1, characterized in that, The satisfaction degrees F of food source, habitat space, and reproduction conditions in S2 js , F jq , F jf The calculation is specifically as follows: The food source satisfaction degree F is calculated by obtaining the biomass and nutrient components of various food resources in the area, and the formula is: js , where the formula is: where P ik is the ingestion preference coefficient of the i-th trophic level fish for the k-th type of food, B jk is the biomass of the k-th type of food in the j-th area, N jk is the comprehensive score of the k-th type of nutrient component in the j-th area, and max(B k ) and max(N k ) are respectively the maximum biomass and the highest nutrient component score of the k-th type of food in the entire water conservancy buffer zone; The satisfaction of the habitat space is calculated by obtaining the water depth suitability S Dj and the water flow velocity S Vj The formula is: F jq =α q ×S Dj +β q ×S Vj where α q and β q are the corresponding weight coefficients; the calculation formula for the water depth suitability S Dj is: where D j is the water depth of the j-th area, and the suitable water depth range is [D min , D max ; the calculation formula for the water flow velocity S Vj is: where V j is the water flow velocity of the j-th area, and the suitable water flow velocity range is [V min , V max ; The satisfaction degree of breeding conditions is calculated by obtaining water temperature, water flow stability and the suitability of breeding substrates, and the formula is: where T j is the water temperature in the j-th area, T opt is the optimal water temperature for fish breeding, R j is the change rate of water flow velocity, Q j is the suitability of breeding substrates, and ω, μ, v are the corresponding weight coefficients.

6. The method for restoring a multi-trophic fish habitat in a water conservancy buffer zone according to claim 1, wherein In S3, when constructing an ecological connectivity model for multi-trophic fish habitats, simulating the migration paths and diffusion abilities of fish between different habitats, and quantifying the connectivity indicators between each habitat, specifically: Obtain the distances between habitats, water flow conditions, and obstacle distributions, and construct a habitat connectivity model. The formula is as follows: is the straight-line distance between the m r th habitat and the n r th habitat, is the hindrance coefficient of water flow to fish migration, is the obstacle influence coefficient, and the connectivity index The larger it is, the better the connectivity between the two habitats.

7. A method for restoring a multi-trophic fish habitat applicable to a water conservancy buffer zone according to claim 1, 5 or 6, characterized in that In S4, determine the target habitats that need to be repaired and optimized according to the connectivity indicators and the ecological requirements of fish at different trophic levels, and determine it by constructing a habitat repair priority index, specifically: Obtain the satisfaction degrees F of the habitat for food sources, habitat spaces, and breeding conditions js , F jq , F jf and the connectivity index between the habitat Construct the restoration priority index P of habitat j j , and the formula is: where h is the number of habitats with a connectivity relationship with habitat j. When P j > T s , it is determined that the habitat j is the target habitat that needs to be restored and optimized, and T s is the restoration priority threshold.

8. A method for restoring fish multi-trophic habitats suitable for a water conservancy buffer zone according to claim 1, characterized in that, The repair strategies in S5 include but are not limited to reshaping the topographic and geomorphic features, creating diverse water flow conditions and habitat microenvironments, optimizing the food web structure by introducing suitable aquatic plants and microbial communities, establishing ecological corridors to restore natural river channels, and enhancing the connectivity of habitat connections.

9. A method for restoring fish multi-trophic habitats applicable to a water conservancy buffer zone according to claim 1, characterized in that, In S5, construct a repair effect evaluation system through a comprehensive evaluation index, specifically: Obtain the habitat population change index P d , the comprehensive environmental change index E c and the material cycle efficiency index M r , calculate the comprehensive evaluation index R, and the formula is: R = α × P d + β × (1 - E c ) + γ × M r , where α, β, and γ are the corresponding weight coefficients. Set different time thresholds R(t) according to different restoration stages. When R < R(t), analyze each sub-index. If P d is low, adjust the food web optimization strategy and increase or replace the types of aquatic organisms released; if E c is high, improve the habitat environment and adjust the water flow conditions to improve the dissolved oxygen content; if M r is low, optimize the ecosystem structure to achieve dynamic adjustment of the restoration strategy according to the evaluation results.

10. A method for restoring multi-trophic habitats for fish in a water conservancy buffer zone according to claim 1, characterized in that, The habitat population change index P d , the environmental comprehensive change index E c and the material cycle efficiency index M r are calculated specifically as follows: Population change index P d Calculated by obtaining the species, quantity, and distribution information of fish at different trophic levels. The formula is: N l0 is the individual quantity of the l-th trophic level fish before restoration, N lt is the quantity at time point t during the restoration process, and m is the total number of monitored trophic level fish species; Environmental Comprehensive Change Index E c Calculated by obtaining key environmental factors such as water temperature, dissolved oxygen content, and pH value. The formula is: Among them, n s represents the total number of environmental factors participating in the evaluation, w q is the weight of the q-th environmental factor, X tq is the actual measured value of the q-th environmental factor at time t during the restoration process; X 0q is the ideal value of the q-th environmental factor. The smaller the E c value, the closer the habitat environment is to the ideal state; Material cycling efficiency index M r Calculated by obtaining the input and output amounts of nitrogen and phosphorus nutrients in the water body and the content changes of nutrients in the sediment. The formula is: Where I is the input amount of nutrients per unit time, O is the output amount, S is the net accumulation amount of nutrients in the sediment, and M r The closer it is to 1, the better the material cycling function of the ecosystem is restored.

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