Method for evaluating influence of lampetra japonica on ecological system where lampetra japonica is located

Abstract

The invention relates to a method for evaluating the influence of lampetra japonica on an ecological system, and belongs to the technical field of ecological system evaluation. The method comprises the following steps: when the lampetra japonica is used as a competitor, acquiring competitor data of the lampetra japonica, constructing a competition network, obtaining competition influence factors, finally constructing an inter-species differential equation, when the lampetra japonica is used as a predator and a predator, acquiring natural enemy and prey species data of the lampetra japonica, constructing an ecological system influence index calculation method, and determining the weight of each index of each species; and counting the score of each species according to the weight. And finally, evaluating the influence of the lampetra japonica on the ecological system according to the competitive species prediction condition and the species score interval. The one-sidedness problem that only the influence of sex of lamprey on the ecological environment is researched in the prior art is solved.

Description

Technical Field

[0001] The invention belongs to the field of ecosystem assessment, and in particular relates to a method for evaluating the impact of sea lampreys on the ecosystem in which they are located. Background Art

[0002] The role of sea lampreys is very complex. Traditional research on the impact of sea lampreys on the ecosystem is mainly reflected in the following: in an environment with insufficient food supply, the proportion of male sea lampreys will reach more than 70%. Conversely, when the food supply is sufficient, the proportion of males will decrease to less than 60%.

[0003] Current research does not take into account the joint relationship of sea lampreys as predators and prey in the ecosystem, and only considers whether there is enough food for sea lampreys, which makes an overly one-sided assessment of the impact on the ecological environment. Summary of the invention

[0004] The present invention proposes an evaluation method for the impact of sea lamprey on the ecosystem in which it is located, which fully considers the joint relationship between sea lamprey and predators and prey in the ecosystem and more comprehensively evaluates the impact on the ecosystem.

[0005] A method for evaluating the impact of sea lamprey on the ecosystem in which it is located comprises the following steps:

[0006] S1: Get the number of species of sea lampreys, their prey and their natural enemies in the ecosystem of a certain area where the sea lampreys are located. By querying the database, the number of individuals of sea lampreys, their prey and their natural enemies in a certain year in the past 10 years in this area is obtained, recorded as X i (k);

[0007] Where X represents the number of individuals of sea lamprey, its prey or its natural enemy;

[0008] i represents the species number. If the number of species of sea lampreys, their prey and their natural enemies in the ecosystem of a certain area is m, then i∈[1,m];

[0009] k represents the year number, k∈[1,10];

[0010] S2: Construct indicators that affect the ecosystem; indicators include: mean standard deviation ratio coefficient, natural growth rate, Shannon index and Simpson diversity index;

[0011] S3: According to the indicators affecting the ecosystem, a decision matrix I is established, and a normalized matrix C is obtained according to the decision matrix I;

[0012] S4: According to the normalized matrix C, determine the weight matrix P, and calculate the stability index weight w according to the weight matrix P j, according to the stability index weight w j , construct the weighted matrix C * ;

[0013] S5: According to the normalized matrix C * , obtain the positive and negative ideal solutions of the prey or natural enemy, and obtain the ideal distances of the positive and negative ideal solutions according to the positive and negative ideal solutions;

[0014] S6: Calculate the ecosystem assessment score based on the ideal distance between the positive and negative ideal solutions and determine the impact on the ecosystem.

[0015] Furthermore, the formula for the mean-standard deviation ratio coefficient is:

[0016]

[0017] The formula for the natural growth rate is:

[0018]

[0019] The formula for the Shannon index is:

[0020]

[0021] Among them, M i It is represented by the annual environmental carrying capacity of species i in the past 10 years, which is a known quantity and a fixed value;

[0022] The formula for Simpson's diversity index is:

[0023]

[0024] Furthermore, in step S3, the decision matrix I is expressed as:

[0025]

[0026] Let I ij Represents the element in the i-th row and j-th column of matrix I, j∈[1,4]; calculate the normalization parameter, the formula is:

[0027]

[0028] The normalized parameters are formed into a matrix form, and the normalized matrix C is:

[0029]

[0030] Let C ij Represents the element in the i-th row and j-th column of matrix C.

[0031] Furthermore, in step S4, the weight parameter is set to P ij , P ijThe calculation formula is:

[0032]

[0033] The weight parameters are written in matrix form, and the weight matrix P is:

[0034]

[0035] P ij Represents the element in the i-th row and j-th column of the matrix P; calculate the information entropy, the formula is:

[0036]

[0037] Calculate the utility value using the formula:

[0038] d j =1-e j

[0039] The weight of the ecosystem stability indicator is calculated using the formula:

[0040]

[0041] Construct the weight matrix C * :

[0042]

[0043] Let C * ij is the matrix C * The element at the i-th row and j-th column in .

[0044] Furthermore, in step S5, the positive ideal solution is:

[0045] C * j + =max{C * 1j ,C * 2j ,......,C * mj}

[0046] The negative ideal solution is: C * j - =min{C * 1j ,C * 2j ,......,C * mj}

[0047] The ideal distance of the positive ideal solution is:

[0048] The ideal distance of the negative ideal solution is:

[0049] Furthermore, in step S6, the calculation formula for the ecosystem assessment score is:

[0050]

[0051] G i The larger the value, the greater the gain to the ecosystem and the greater the impact on the ecosystem.

[0052] Beneficial effects:

[0053] When sea lampreys act as predators and prey, we obtain data on their natural enemies and prey species, build a calculation method for ecosystem impact indicators, determine the weights of each indicator for each species, and calculate the scores of each species based on the weights. Finally, we can evaluate the impact of sea lampreys on their ecosystems based on the predicted competitive species and the species score range. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 is a flow chart of the method. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] See Figure 1 , a method for evaluating the impact of sea lamprey on the ecosystem in which it is located, comprising the following steps:

[0057] S1: Obtain the species number of sea lampreys, their prey and their natural enemies in the ecosystem of a certain area where the sea lampreys are located, query the database, and obtain the individual number of sea lampreys, their prey and their natural enemies in a certain year in the past 10 years.

[0058] Suppose the number of sea lampreys, their prey, and their natural enemies in a certain year in the past 10 years is X. i (k);

[0059] Where X represents the number of individuals of sea lamprey, its prey or its natural enemy;

[0060] i represents the species number. In this embodiment, assuming that the number of species of sea lampreys, their prey and their natural enemies in the ecosystem of a certain area where sea lampreys are located is m, then i∈[1,m];

[0061] k represents the year number, k∈[1,10]; k=1 represents the time range of 1 year from now; k=2 represents the time range of 2 years from now to 1 year from now; and so on.

[0062] S2: Construct an indicator of ecosystem impact based on the number of sea lampreys, their prey, or their natural enemies captured in a single year over the past 10 years.

[0063] The specific steps include:

[0064] S2.1: Construct the mean standard deviation ratio coefficient, the formula is:

[0065]

[0066] in, It represents the average annual number of individuals of species i in the past 10 years.

[0067] S2.2: Construct the natural growth rate, the formula is:

[0068]

[0069] S2.3: Construct the Shannon index, the formula is:

[0070]

[0071] Among them, M i It is expressed as the annual environmental carrying capacity of species i in the past 10 years, which is a known quantity and a constant value.

[0072] S2.4: Simpson diversity index, the formula is:

[0073]

[0074] S3: According to the indicators that affect the ecosystem, a decision matrix I is constructed, and a normalized matrix C is obtained based on the decision matrix I.

[0075] The decision matrix I is expressed as:

[0076]

[0077] Let I ij Represents the element in the i-th row and j-th column of matrix I, j∈[1,4]; calculate the normalization parameter, the formula is:

[0078]

[0079] The normalization parameters are formed into a matrix form, and the normalization matrix C is:

[0080]

[0081] Let C ij Represents the element in the i-th row and j-th column of matrix C;

[0082] S4: According to the normalized matrix C, determine the weight matrix P, and calculate the stability index weight w according to the weight matrix P j , according to the stability index weight w j , construct the weighted matrix C * .

[0083] Let the weight parameter be P ij , P ij The calculation formula is:

[0084]

[0085] The weight parameters are written in matrix form, and the weight matrix is:

[0086]

[0087] Then, P ij Represents the element in the i-th row and j-th column of the matrix P. The information entropy is calculated using the formula:

[0088]

[0089] Calculate the utility value using the formula:

[0090] d j =1-e j

[0091] The weight of the ecosystem stability indicator is calculated using the formula:

[0092]

[0093] Construct the weight matrix C * :

[0094]

[0095] Let C * ij is the matrix C * The element in row i and column j;

[0096] S5: According to the normalized matrix C * , obtain the positive and negative ideal solutions of prey or natural enemies, and based on the positive and negative ideal solutions, obtain the ideal distances of the positive and negative ideal solutions.

[0097] According to the normalized matrix C * , obtain positive and negative ideal solutions;

[0098] Among them, the positive ideal solution is:

[0099] C * j + =max{C * 1j ,C * 2j ,......,C * mj}

[0100] The negative ideal solution is:

[0101] C * j - =min{C * 1j ,C * 2j ,......,C * mj}

[0102] According to the positive and negative ideal solutions, the ideal distances of the positive and negative ideal solutions are calculated;

[0103] Among them, the ideal distance of the positive ideal solution is:

[0104]

[0105] The ideal distance of the negative ideal solution is:

[0106]

[0107] S6: Calculate the ecosystem assessment score based on the ideal distance between the positive and negative ideal solutions and determine the impact on the ecosystem.

[0108] The formula is:

[0109] G i The value range of G is (0, 1). i It is divided into three intervals, namely (0, 0.33], (0.33, 0.66] and (0.66, 1), G i The larger the value of , the greater the gain to the ecosystem and the greater the impact on the ecosystem; conversely, the smaller the impact on the ecosystem. The three intervals (0, 0.33], (0.33, 0.66] and (0.66, 1) are artificially identified as having small, medium and large impacts on the ecosystem.

[0110] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A method for evaluating the impact of sea lampreys on their ecosystem, characterized in that: The following steps are involved: S1: Get the number of species of sea lampreys, their prey and their natural enemies in the ecosystem of a certain area where the sea lampreys are located. By querying the database, the number of individuals of sea lampreys, their prey and their natural enemies in a certain year in the past 10 years in this area is obtained, recorded as X i (k); Where X represents the number of individuals of sea lamprey, its prey or its natural enemy; i represents the species number. If the number of species of sea lampreys, their prey and their natural enemies in the ecosystem of a certain area is m, then i∈[1,m]; k represents the year number, k∈[1,10]; S2: Construct indicators that affect the ecosystem; indicators include: mean standard deviation ratio coefficient, natural growth rate, Shannon index and Simpson diversity index; S3: According to the indicators affecting the ecosystem, a decision matrix I is established, and a normalized matrix C is obtained according to the decision matrix I; S4: According to the normalized matrix C, determine the weight matrix P, and calculate the stability index weight w according to the weight matrix P j , according to the stability index weight w j , construct the weighted matrix C * ; S5: According to the normalized matrix C * , obtain the positive and negative ideal solutions of the prey or natural enemy, and obtain the ideal distances of the positive and negative ideal solutions according to the positive and negative ideal solutions; S6: Calculate the ecosystem assessment score based on the ideal distance between the positive and negative ideal solutions and determine the impact on the ecosystem.

2. The method for evaluating the impact of sea lamprey on the ecosystem according to claim 1, characterized in that: In step S2, the formula for the mean standard deviation ratio coefficient is: The formula for the natural growth rate is: The formula for the Shannon index is: Among them, M i It is represented by the annual environmental carrying capacity of species i in the past 10 years, which is a known quantity and a fixed value; The formula for Simpson's diversity index is:

3. The method for evaluating the impact of sea lamprey on the ecosystem according to claim 2, characterized in that: In step S3, the decision matrix I is expressed as: Let I ij Represents the element in the i-th row and j-th column of matrix I, j∈[1,4]; Calculate the normalization parameter, the formula is: The normalized parameters are formed into a matrix form, and the normalized matrix C is: Let C ij Represents the element in the i-th row and j-th column of matrix C.

4. The method for evaluating the impact of sea lamprey on the ecosystem according to claim 3, characterized in that: In step S4, the weight parameter is set to P ij , P ij The calculation formula is: The weight parameters are written in matrix form, and the weight matrix is: P ij represents the element in the i-th row and j-th column of the matrix P; Calculate information entropy, the formula is: Calculate the utility value using the formula: d j =1-e j The weight of the ecosystem stability indicator is calculated using the formula: Construct the weight matrix C * : Let C * ij is the matrix C * The element at the i-th row and j-th column in .

5. The method for evaluating the impact of sea lamprey on the ecosystem according to claim 4, characterized in that: In step S5, the positive ideal solution is: C * j + =max{C * 1j ,C * 2j ,......,C * mj } The negative ideal solution is: C * j - =min{C * 1j ,C * 2j ,......,C * mj } The ideal distance of the positive ideal solution is: The ideal distance of the negative ideal solution is:

6. The method for evaluating the impact of sea lamprey on the ecosystem according to claim 4, characterized in that: In step S6, the calculation formula for the ecosystem assessment score is: G i The larger the value, the greater the gain to the ecosystem and the greater the impact on the ecosystem.

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