A rapid assessment method for aquatic ecological damage based on indicator species environmental DNA

Abstract

This invention belongs to the field of aquatic ecological damage assessment technology, specifically relating to a rapid assessment method for aquatic ecological damage based on the environmental DNA of indicator species. The method first establishes a clean indicator species library, then deploys sampling points along the damage source to the diffusion area, obtaining the eDNA copy number of each clean indicator species at the sampling points. Next, based on the eDNA copy number of clean indicator species, the eDNA copy number-biomass model, and the enrichment fold, the biomass of the clean indicator species is calculated. Subsequently, the ecological baseline of each clean indicator species is obtained, and the ecological damage index of the sampling points is calculated based on the biomass exceedance rate of all clean indicator species. Finally, based on the ecological damage index of each sampling point and its distance from the damage source, an ecological damage distance decay regression model is fitted to predict the ecological damage index downstream of the damage source in the assessed water area. This invention enables rapid assessment of the degree and extent of ecological damage.

Description

Technical Field

[0001] This invention belongs to the field of water ecological damage assessment technology, specifically relating to a rapid water ecological damage assessment method based on indicator species environmental DNA. Background Technology

[0002] Traditional methods for assessing water ecological damage, such as the system proposed in "A Method and System for Assessing Damage to Freshwater Ecosystems" (patent application number 2024116335776), primarily rely on comprehensive monitoring of multiple indicators related to the physicochemical parameters of water bodies and aquatic biological communities (such as plankton, benthic animals, and fish). While these methods offer comprehensive assessments, they involve numerous indicators and suffer from significant drawbacks, including cumbersome sample collection, lengthy laboratory analysis cycles, reliance on specialized taxonomists for species identification, and high costs in terms of human and material resources. This makes it difficult to respond quickly and provide assessment results in the event of sudden water ecological damage incidents (such as chemical leaks or illegal discharges), potentially missing the optimal window for ecological restoration and emergency decision-making.

[0003] Environmental DNA (eDNA) technology offers a new solution for aquatic ecosystem monitoring. By detecting the genetic material of organisms in water bodies, eDNA can efficiently obtain information on community composition and biomass, thus providing a faster way to assess the state of aquatic ecosystem damage. Patent application number 202110043570.9 provides a method and system for aquatic ecosystem analysis based on eDNA. This method can establish a predictive model based on environmental parameters (IBI index) and biological parameters (RIVPACS index), and use the predictive model to analyze the health status of aquatic ecosystems. However, the aforementioned existing technologies mainly use eDNA technology to identify the quantity and proportion of organisms in aquatic ecosystems and evaluate biodiversity in specific areas, but cannot achieve rapid assessment of aquatic ecosystem damage. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned problems in the existing technology by providing a rapid assessment method for aquatic ecological damage based on indicator species environmental DNA, which enables rapid assessment of aquatic ecological damage.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A rapid assessment method for aquatic ecological damage based on indicator species environmental DNA, the rapid assessment method for aquatic ecological damage comprising:

[0007] S1. Establish a clean indicator species bank in the assessment waters, wherein the biomass of the clean indicator species in the assessment waters decreases with the increase of the degree of ecological damage, and the clean indicator species cover at least two groups among fish, phytoplankton, zooplankton, benthic animals, and aquatic plants.

[0008] S2. Several sampling points were set up along the damage source to the diffusion area in the assessment water area. At each sampling point, water samples were collected and enriched using an eDNA enrichment system. The clean indicator species in the enriched water samples were subjected to eDNA extraction, PCR amplification and fluorescence quantification to obtain the eDNA copy number of the clean indicator species.

[0009] S3. Based on the eDNA copy number of the clean indicator species obtained in S2, the pre-constructed eDNA copy number-biomass model of the clean indicator species, and the enrichment fold of the eDNA enrichment system, calculate the biomass of the clean indicator species.

[0010] S4. Obtain the ecological baseline for each clean indicator species, and calculate the ecological damage index of the sampling points based on the biomass exceedance rate of all clean indicator species.

[0011] S5. Based on the ecological damage index of each sampling point and its distance from the damage source, an ecological damage distance decay regression model is fitted. The ecological damage distance decay regression model is used to predict the ecological damage index downstream of the damage source in the assessment water area, and to assess the ecological damage range based on the ecological damage index.

[0012] In S4, the formula for calculating the ecological damage index is:

[0013] ;

[0014] ;

[0015] In the above formula, This represents the ecological damage index. For the first The rate of biomass exceeding baseline for each clean indicator species; For the first An ecological baseline for the biomass of a clean indicator species; The first [number]th ... Biomass of one indicator species; For the first The weight of each clean indicator species; , These are the first correction factor and the second correction factor, respectively. The number of clean indicator species.

[0016] The assessment of the degree of ecological damage based on the ecological damage index includes:

[0017] An ecological damage level classification standard is set: an ecological damage index of less than 1.2 indicates no damage, 1.2 ≤ ecological damage index < 1.5 indicates slight damage, 1.5 ≤ ecological damage index < 2 indicates moderate damage, and an ecological damage index ≥ 2 indicates severe damage.

[0018] In S4, the method for obtaining the ecological baseline of the clean indicator species includes:

[0019] First, calculate the ecological baseline of indicator species biomass using the ternary method and the quartile method respectively;

[0020] Then, the number of clean indicator species with environmental stress discrimination ability in each ecological baseline determination method is obtained. The method with more clean indicator species with environmental stress discrimination ability is selected as the final ecological baseline. If the number of clean indicator species with environmental stress discrimination ability is the same in the two methods, the average of the two is taken as the final ecological baseline.

[0021] For fish, the selected clean indicator species include: Culter alburnus, Pheasant simonii, Gizzard bream, Yellowtail flounder, and Fighting fish.

[0022] For phytoplankton, the selected cleanliness indicator species include: Chlamydomonas simplex, Cryptophyta, Cryptophyta ovoidea, Cyclophyta, and Sedum.

[0023] For zooplankton, the selected clean indicator species include *Dendrobium*, *Daphnia longhornula*, and *Bellaria wangi*.

[0024] For benthic animals, the selected clean indicator species include the genera *Tetrasporium*, *Tetrasporium biwingum*, *Tetrasporium*, *Tetrasporium spp.*, and *Tetrasporium sinense*.

[0025] For aquatic plants, the selected cleanliness indicator species include *Gnaphalium affine*, *Chara*, *Agave salsa*, and *Ottelia acuminata*.

[0026] The number of clean indicator species is 4-10.

[0027] The following methods can be used to determine whether a clean indicator species in a single ecological baseline determination method has the ability to discriminate environmental stress:

[0028] First, the biomass of a certain clean indicator species at all sampling points is sorted from largest to smallest, and then divided into reference points and damaged points according to the selected ecological baseline determination method. When the selected ecological baseline determination method is the three-thirds method, the first 1 / 3 is selected as reference points and the rest as damaged points. When the selected ecological baseline determination method is the quartile method, the first 25% is selected as reference points and the rest as damaged points.

[0029] Then, the box plot scoring method was used to compare the overlap between the reference point and the median of the 25-75% quantile of the interquartile range and the median, and different scores were assigned according to the overlap.

[0030] Finally, determine whether the score of the clean indicator species is ≥2. If it is, it means that the clean indicator species has the ability to distinguish environmental stress; otherwise, it means that the clean indicator species does not have the ability to distinguish environmental stress.

[0031] The method of assigning different scores based on overlap includes:

[0032] If the interquartile distances between the reference point and the damaged point do not overlap, the score is 3.

[0033] If the interquartile ranges of the reference point and the damaged point partially overlap, but their respective medians are outside the range of the other's interquartile range, then the score is 2.

[0034] If the interquartile ranges of the reference point and the damaged point partially overlap, but the median of either the reference point or the damaged point is within the range of the other's interquartile range, then the score is 1.

[0035] If the interquartile ranges of the reference point and the damaged point partially overlap, and the medians of both the reference point and the damaged point are within the range of the other's interquartile range, then the score is 0.

[0036] The three-thirds method involves arranging the biomass of all sampling points for clean indicator species from largest to smallest, and then selecting the median of the first third as the ecological baseline for that clean indicator species. The four-quartile method involves arranging the biomass of all sampling points for clean indicator species from largest to smallest, and then selecting the first 25% quartile as the ecological baseline for that clean indicator species.

[0037] For river water bodies, multiple sampling points were set up 200-500 meters upstream of the source of damage and along the downstream route of the source of damage;

[0038] For lakes or reservoirs, multiple sampling points are set up at the source of damage and along the direction of water flow centered on the source of damage.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] 1. In the rapid water ecological damage assessment method of this invention, a clean indicator species library is established for the assessment water area. The ecological damage index is calculated based on the biomass exceedance rate of all clean indicator species. Since the biomass of clean indicator species in the assessment water area decreases with the increase of ecological damage, only a few clean indicator species are needed to clearly indicate the degree of ecological damage while significantly reducing the workload of environmental DNA extraction, simplifying the calculation of the ecological damage index, and thus achieving rapid assessment of the degree of ecological damage. This method can achieve the assessment of the degree of ecological damage faster than traditional methods that rely on water quality and aquatic biological communities for water ecological damage assessment (such as patent application number 2024116335776). In the event of sudden water ecological damage events (such as chemical leaks and illegal discharges), it can quickly respond and trace the source of damage. 2. In the rapid water ecological damage assessment method of this invention, based on the ecological damage index of each sampling point and its distance from the damage source, an ecological damage distance decay regression model is fitted. The ecological damage distance decay regression model is used to predict the ecological damage index downstream of the damage source in the assessment water area, thereby realizing the assessment of the maximum damage range and the impact range of different damage levels.

[0041] 2. In the rapid assessment method for water ecological damage described in this invention, the number of clean indicator species with environmental stress discrimination ability in each ecological baseline determination method is obtained by using the box plot scoring method. The results obtained by the method with more clean indicator species with environmental stress discrimination ability are preferentially selected as the final ecological baseline, which is conducive to improving the accuracy of the final assessment results. Attached Figure Description

[0042] Figure 1 This is a schematic diagram showing the deployment of sampling points for a lake in the middle reaches of the Yangtze River.

[0043] Figure 2 This is a comparison chart of the ecological damage index obtained by the method described in this invention and the water ecological damage index obtained by method 1.

[0044] Figure 3 This is a comparison chart of the ecological damage index obtained by the method described in this invention and the water ecological damage index obtained by method 2.

[0045] Figure 4 This is a schematic diagram of the ecological damage distance decay regression model obtained by the method described in this invention. Detailed Implementation

[0046] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0047] This invention provides a rapid assessment method for aquatic ecological damage based on indicator species environmental DNA, the method comprising the following steps:

[0048] S1. By using long-term monitoring data and reviewing existing literature, establish a clean indicator species library in the assessment waters, wherein the biomass of the clean indicator species in the assessment waters decreases with the increase of ecological damage.

[0049] Preferably, to balance the economy and accuracy of subsequent environmental DNA testing, the number of clean indicator species is 4-10.

[0050] Preferably, to ensure the accuracy of the assessment results, the cleanliness indicator species cover at least two groups from fish, phytoplankton, zooplankton, benthic animals, and aquatic plants, as detailed in Table 1:

[0051] Table 1. Cleanliness indicator species of different taxa

[0052]

[0053] S2. Several sampling points are set up along the damage source to the diffusion area in the assessment water area. At each sampling point, water samples (not less than 3L) are collected and enriched using an eDNA enrichment system. The enriched filter membrane is sent back to the laboratory either on-site or stored at -20℃. The eDNA of the clean indicator species is extracted, PCR amplified and quantified according to the standard "Aquatic Ecological Monitoring Environmental DNA Fluorescent Quantitative PCR Method" (T / SEEPLA 08-2024) to obtain the eDNA copy number of the clean indicator species.

[0054] Preferably, for river bodies, multiple sampling points (e.g., 200m, 500m, 1000m, 1500m, 2000m, 2500m) are set up 200-500 meters upstream of the damage source and along the downstream of the damage source; for lakes or reservoirs, multiple sampling points (e.g., 200m, 500m, 1000m, 1500m, 2000m, 2500m) are set up at the damage source and along the direction of water flow centered on the damage source.

[0055] S3. Based on the eDNA copy number of the clean indicator species obtained in S2, the pre-constructed eDNA copy number-biomass model of the clean indicator species, and the enrichment fold of the eDNA enrichment system, calculate the biomass of the clean indicator species.

[0056] S4. Obtain the ecological baseline for each clean indicator species, and calculate the ecological damage index of the sampling points based on the biomass exceedance rate of all clean indicator species.

[0057] Preferably, the formula for calculating the ecological damage index is:

[0058] ;

[0059] ;

[0060] In the above formula, This represents the ecological damage index. For the first The rate of biomass exceeding baseline for each clean indicator species; For the first An ecological baseline for the biomass of a clean indicator species; The first [number]th ... Biomass of one indicator species; For the first The weight of each clean indicator species is the reciprocal of the number of clean indicator species. , These are the first correction factor and the second correction factor, respectively, and preferably, both are set to 0.5; The number of clean indicator species.

[0061] Preferably, the method for obtaining the ecological baseline of the clean indicator species includes:

[0062] First, the ecological baseline of indicator species biomass was determined using the ternary method and the quartile method, respectively. Then, the number of clean indicator species with environmental stress discrimination ability was obtained for each ecological baseline determination method. The method with more clean indicator species with environmental stress discrimination ability was selected as the final ecological baseline. If the number of clean indicator species with environmental stress discrimination ability was the same in the two methods, the average of the two methods was taken as the final ecological baseline.

[0063] Preferably, the ability of clean indicator species to discriminate environmental stress in a single ecological baseline determination method is determined according to the following method:

[0064] First, the biomass of a certain clean indicator species at all sampling points is sorted from largest to smallest, and then divided into reference points and damaged points according to the selected ecological baseline determination method. When the selected ecological baseline determination method is the three-thirds method, the first 1 / 3 is selected as reference points and the rest as damaged points. When the selected ecological baseline determination method is the quartile method, the first 25% is selected as reference points and the rest as damaged points.

[0065] Then, the box plot scoring method was used to compare the overlap between the reference point and the median of the 25-75% quantile of the interquartile range and the median, and different scores were assigned according to the overlap.

[0066] Finally, determine whether the score of the clean indicator species is ≥2. If it is, it means that the clean indicator species has the ability to distinguish environmental stress; otherwise, it means that the clean indicator species does not have the ability to distinguish environmental stress.

[0067] It should be noted that if the number of reference points is insufficient (e.g., less than 3), it is impossible to test whether the environmental pressure discrimination capability is available using the box plot scoring method. In order to reduce the impact of outliers on the assessment results, the average of the results obtained by the two methods is used as the final ecological baseline.

[0068] Preferably, assigning different scores based on overlap includes:

[0069] If the interquartile distances between the reference point and the damaged point do not overlap, the score is 3.

[0070] If the interquartile ranges of the reference point and the damaged point partially overlap, but their respective medians are outside the range of the other's interquartile range, then the score is 2.

[0071] If the interquartile ranges of the reference point and the damaged point partially overlap, but the median of either the reference point or the damaged point is within the range of the other's interquartile range, then the score is 1.

[0072] If the interquartile ranges of the reference point and the damaged point partially overlap, and the medians of both the reference point and the damaged point are within the range of the other's interquartile range, then the score is 0.

[0073] Preferably, the three-thirds method involves arranging the biomass of all sampling points for the clean indicator species from largest to smallest, and then selecting the median of the first third as the ecological baseline for that clean indicator species. The four-quartile method involves arranging the biomass of all sampling points for the clean indicator species from largest to smallest, and then selecting the first 25% quartile as the ecological baseline for that clean indicator species.

[0074] S5. Based on the ecological damage index of each sampling point and its distance from the damage source, an ecological damage distance decay regression model is fitted. The ecological damage distance decay regression model is used to predict the ecological damage index downstream of the damage source in the assessment water area, and to assess the degree of ecological damage based on the ecological damage index.

[0075] The horizontal distance between the sampling point in the river and the damage source can be obtained based on the length of the river section, while the horizontal distance between the vegetable sampling point in the lake and the damage source can be estimated based on the arc of the lake flow direction.

[0076] Preferably, the assessment of the degree of ecological damage based on the ecological damage index includes: setting a standard for classifying the degree of ecological damage, where an ecological damage index less than 1.2 indicates no damage, 1.2 ≤ ecological damage index < 1.5 indicates mild damage, 1.5 ≤ ecological damage index < 2 indicates moderate damage, and an ecological damage index ≥ 2 indicates severe damage.

[0077] Application Examples:

[0078] Suspected illegal discharge of aquaculture wastewater near the inlet of a lake in the middle reaches of the Yangtze River has caused an algal bloom in parts of the lake. To assess the extent of ecological damage caused by the aquaculture wastewater, such as... Figure 1 As shown, eight sampling points (S1-S8) were set up from the river inlet to the lake along the lake flow direction, and the rapid assessment method for water ecological damage described in this invention was applied to conduct the investigation. 3L of water samples were enriched on-site, and the enriched filter membrane was stored at -20℃ and sent back to the laboratory for DNA extraction, PCR amplification, and quantitative fluorescence analysis. The biomass of seven clean indicator species was calculated, as shown in Table 2, and the final ecological baseline is shown in Table 3.

[0079] Table 2. Biomass of Clean Indicator Species (g / L)

[0080]

[0081] Table 3 Ecological baselines (g / L) for clean indicator species

[0082]

[0083] Based on the data in Table 3, the calculations for each sampling point were performed. and ecological damage index like Figure 2 As shown. From Figure 2 As can be seen, the ecological damage at S1, located at the lake inlet, is the most severe, classified as moderate. This is followed by S2, S3, S5, S6, and S7, all of which show slight damage. S6 and S8 remain undamaged. Among the seven clean indicator species, *Gnaphalium affine* is the most sensitive to the lake's ecological damage, showing severe damage at more than half of the sampling sites. This is followed by *Daphnia longibrownense* and *Cyclophora*, which also showed severe damage at some sampling sites. The other clean indicator species are mainly undamaged to moderately damaged.

[0084] Two methods were used to verify the accuracy of the ecological damage assessment results. Method 1 is the method proposed in invention patent application number 202411633577.6, which involves applying the ecological damage index obtained by the method described in this invention. Compared with the water ecological damage index obtained by application method 1 A consistency comparison was performed; the results are shown below. Figure 2 As can be seen, the degree of ecological damage is consistent across 7 out of all sampling points. Method 2 is the method proposed in invention patent application number 202411633577.6, which compares the degree of ecological damage obtained by applying the method described in this invention with the ecological damage index obtained by applying method 2. Regression analysis was performed; the results are shown below. Figure 3 Its correlation coefficient R 2The accuracy is 0.880 and the root mean square error (RMSE) is 0.077, demonstrating high precision. In summary, this invention, based on the cDNA of clean indicator species, achieves high detection accuracy for ecological damage assessment while significantly reducing workload, enabling rapid and accurate assessment of aquatic ecological damage.

[0085] Using the ecological damage index of each sampling point The distance between the sampling point and the damage source is used to establish a system as follows: Figure 4 The ecological damage distance decay regression model shown predicts that the waters within 225 meters downstream of the lake source will cause moderate ecological damage. A concentration greater than 1.5 can cause minor ecological damage to waters within a 1230-meter radius downstream of the lake's flow direction. (Greater than 1.2), the maximum impact range on the lake is 2438 meters downstream along the lake flow direction. In summary, this invention can predict the ecological damage index downstream of the water damage source through an ecological damage distance decay regression model, thereby enabling the assessment of the impact range and maximum damage range of different damage levels.

Claims

1. A rapid assessment method for aquatic ecological damage based on indicator species environmental DNA, characterized in that: The rapid assessment method for water ecological damage includes: S1. Establish a clean indicator species bank in the assessment waters, wherein the biomass of the clean indicator species in the assessment waters decreases with the increase of the degree of ecological damage, and the clean indicator species cover at least two groups among fish, phytoplankton, zooplankton, benthic animals, and aquatic plants. S2. Several sampling points were set up along the damage source to the diffusion area in the assessment water area. At each sampling point, water samples were collected and enriched using an eDNA enrichment system. The clean indicator species in the enriched water samples were subjected to eDNA extraction, PCR amplification and fluorescence quantification to obtain the eDNA copy number of the clean indicator species. S3. Based on the eDNA copy number of the clean indicator species obtained in S2, the pre-constructed eDNA copy number-biomass model of the clean indicator species, and the enrichment fold of the eDNA enrichment system, calculate the biomass of the clean indicator species. S4. Obtain the ecological baseline for each clean indicator species, and calculate the ecological damage index of the sampling points based on the biomass exceedance rate of all clean indicator species. S5. Based on the ecological damage index of each sampling point and its distance from the damage source, an ecological damage distance decay regression model is fitted. The ecological damage distance decay regression model is used to predict the ecological damage index downstream of the damage source in the assessment water area, and to assess the ecological damage range based on the ecological damage index.

2. The rapid assessment method for aquatic ecological damage based on indicator species environmental DNA according to claim 1, characterized in that: In S4, the formula for calculating the ecological damage index is: ； ； In the above formula, This represents the ecological damage index. For the first The rate of biomass exceeding baseline for each clean indicator species; For the first An ecological baseline for the biomass of a clean indicator species; The first [number]th ... Biomass of one indicator species; For the first The weight of each clean indicator species; , These are the first correction factor and the second correction factor, respectively. The number of clean indicator species.

3. A rapid assessment method for aquatic ecological damage based on indicator species environmental DNA according to claim 1 or 2, characterized in that: The assessment of the degree of ecological damage based on the ecological damage index includes: An ecological damage level classification standard is set: an ecological damage index of less than 1.2 indicates no damage, 1.2 ≤ ecological damage index < 1.5 indicates slight damage, 1.5 ≤ ecological damage index < 2 indicates moderate damage, and an ecological damage index ≥ 2 indicates severe damage.

4. A rapid assessment method for aquatic ecological damage based on indicator species environmental DNA according to claim 1 or 2, characterized in that: In S4, the method for obtaining the ecological baseline of the clean indicator species includes: First, calculate the ecological baseline of indicator species biomass using the ternary method and the quartile method respectively; Then, the number of clean indicator species with environmental stress discrimination ability in each ecological baseline determination method is obtained. The method with more clean indicator species with environmental stress discrimination ability is selected as the final ecological baseline. If the number of clean indicator species with environmental stress discrimination ability is the same in the two methods, the average of the two is taken as the final ecological baseline.

5. A rapid assessment method for aquatic ecological damage based on indicator species environmental DNA according to claim 1 or 2, characterized in that: For fish, the selected clean indicator species include: Culter alburnus, Pheasant simonii, Gizzard bream, Yellowtail flounder, and Fighting fish. For phytoplankton, the selected cleanliness indicator species include: Chlamydomonas simplex, Cryptophyta, Cryptophyta ovoidea, Cyclophyta, and Sedum. For zooplankton, the selected clean indicator species include *Dendrobium*, *Daphnia longhornula*, and *Bellaria wangi*. For benthic animals, the selected clean indicator species include the genera *Tetrasporium*, *Tetrasporium biwingum*, *Tetrasporium*, *Tetrasporium spp.*, and *Tetrasporium sinense*. For aquatic plants, the selected cleanliness indicator species include *Gnaphalium affine*, *Chara*, *Agave salsa*, and *Ottelia acuminata*.

6. A rapid assessment method for aquatic ecological damage based on indicator species environmental DNA according to claim 1 or 2, characterized in that: The number of clean indicator species is 4-10.

7. The rapid assessment method for aquatic ecological damage based on indicator species environmental DNA according to claim 4, characterized in that: The following methods can be used to determine whether a clean indicator species in a single ecological baseline determination method has the ability to discriminate environmental stress: First, the biomass of a certain clean indicator species at all sampling points is sorted from largest to smallest, and then divided into reference points and damaged points according to the selected ecological baseline determination method. When the selected ecological baseline determination method is the three-thirds method, the first 1 / 3 is selected as reference points and the rest as damaged points. When the selected ecological baseline determination method is the quartile method, the first 25% is selected as reference points and the rest as damaged points. Then, the box plot scoring method was used to compare the overlap between the reference point and the median of the 25-75% quantile of the interquartile range and the median, and different scores were assigned according to the overlap. Finally, determine whether the score of the clean indicator species is ≥2. If it is, it means that the clean indicator species has the ability to distinguish environmental stress; otherwise, it means that the clean indicator species does not have the ability to distinguish environmental stress.

8. The rapid assessment method for aquatic ecological damage based on indicator species environmental DNA according to claim 7, characterized in that: The method of assigning different scores based on overlap includes: If the interquartile distances between the reference point and the damaged point do not overlap, the score is 3. If the interquartile ranges of the reference point and the damaged point partially overlap, but their respective medians are outside the range of the other's interquartile range, then the score is 2. If the interquartile ranges of the reference point and the damaged point partially overlap, but the median of either the reference point or the damaged point is within the range of the other's interquartile range, then the score is 1. If the interquartile ranges of the reference point and the damaged point partially overlap, and the medians of both the reference point and the damaged point are within the range of the other's interquartile range, then the score is 0.

9. The rapid assessment method for aquatic ecological damage based on indicator species environmental DNA according to claim 4, characterized in that: The three-thirds method involves arranging the biomass of all sampling points for clean indicator species from largest to smallest, and then selecting the median of the first third as the ecological baseline for that clean indicator species. The four-quartile method involves arranging the biomass of all sampling points for clean indicator species from largest to smallest, and then selecting the first 25% quartile as the ecological baseline for that clean indicator species.

10. A rapid assessment method for aquatic ecological damage based on indicator species environmental DNA according to claim 1 or 2, characterized in that: For river water bodies, multiple sampling points were set up 200-500 meters upstream of the source of damage and along the downstream route of the source of damage; For lakes or reservoirs, multiple sampling points are set up at the source of damage and along the direction of water flow centered on the source of damage.

Images