Comprehensive evaluation method and system for the degree of habitat fragmentation of fish populations

Abstract

The present invention discloses a comprehensive evaluation method for the degree of fragmentation of fish population habitats, including obtaining preset distribution data of fish in the area to be studied, including: river network data, sub-basin data and basin river obstacle data; calculating the population diffusion capacity of each fish according to the preset fish data; reconstructing the fish habitat range according to the population diffusion capacity, preset distribution data and fish habit data; calculating the degree of fragmentation of fish population habitats according to the habitat range, population diffusion capacity and basin river obstacle data. The comprehensive evaluation method for the degree of fragmentation of fish population habitats of the present invention can be applied to evaluate the impact of river obstacles on fish habitats, and construct the fish habitat range, and fully conduct a comprehensive evaluation of the degree of fragmentation of the habitat of a specific species.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental assessment, and in particular to a comprehensive assessment method, system, computer medium and computer for the degree of habitat fragmentation of fish populations. Background Art

[0002] To meet people's needs for water supply, energy and flood control, river infrastructure including hydropower facilities, reservoir dams, weirs, bridge foundations and sluices have been built in many rivers around the world. However, these river infrastructures (hereinafter referred to as "river barriers") can also have a negative impact on aquatic ecosystems, leading to changes in aquatic environments and loss of biodiversity. River barriers destroy the continuity of river ecosystems, reduce river connectivity, hinder the spread of aquatic organisms, and in many cases lead to changes in biological communities. For migratory fish, river barriers can block migration routes, isolate populations, and reduce the availability of spawning grounds and other critical habitats. For sedentary fish, barriers limit their spread and the recruitment of heterogeneous populations. Studies have shown that the construction of barriers is one of the main reasons for the decline in populations and local extinction of many economically important species, including European sturgeon, brown trout and European eel.

[0003] As the urgency of fish protection and watershed management increases, it is necessary to clearly understand the impact of river barriers on the connectivity of fish habitats at a large scale. Therefore, it is necessary to evaluate river connectivity to analyze the impact of river barrier construction on fish habitats. At present, the existing river connectivity and habitat fragmentation evaluation methods are mostly limited to network theory, which models the river system as a network structure and evaluates the overall connectivity and key nodes of the river by analyzing the topological structure and connection relationship of the network. The river connectivity evaluation based on network theory describes the river system in a network manner and calculates the connectivity of the river system based on the connectivity between river sections. In this method, the river system is mostly a tree structure, and its topological structure can be generalized as a unidirectional directed graph.

[0004] However, the existing methods for evaluating river connectivity and habitat fragmentation have some limitations. First, some methods do not fully consider biological indicators in rivers, such as fish, and therefore cannot comprehensively assess the impact of river barriers on fish habitats. Second, some evaluation methods only focus on migratory fish, but do not consider the impact of barrier construction on non-migratory fish, and do not consider the migration distance and dispersal capacity of fish in rivers. There is a lack of comprehensive consideration of the range of fish habitats, and therefore, they cannot fully conduct a comprehensive fragmentation evaluation of the habitat of a specific species.

[0005] Therefore, there is an urgent need for a comprehensive evaluation method that can be used to evaluate the impact of river obstacles on fish habitats, construct the range of fish habitats, and fully evaluate the degree of fragmentation of the habitat of a specific species. Summary of the invention

[0006] Purpose of the invention: In order to overcome the above shortcomings, the purpose of the present invention is to provide a comprehensive evaluation method for the degree of fragmentation of fish population habitats, which is used for the comprehensive evaluation of the fragmentation of fish habitats at the basin scale. It is a comprehensive evaluation method for the impact of engineering construction such as reservoir dams, weirs, and sluices on the integrity of river ecosystems, resulting in reduced river connectivity and fragmentation of fish habitats.

[0007] In order to solve the above technical problems, the present invention provides a comprehensive evaluation method for the degree of habitat fragmentation of fish populations, comprising:

[0008] Step S1: obtaining preset distribution data of fish in the area to be studied, including: river network data, sub-basin data and basin river obstacle data;

[0009] Step S2: Calculate the population diffusion capacity of each fish species according to the preset fish data;

[0010] Step S3: reconstructing the fish habitat range according to the population diffusion capacity, preset distribution data and fish habit data;

[0011] Step S4: Calculate the degree of habitat fragmentation of fish populations based on habitat range, population dispersal capacity and river obstacle data in the basin.

[0012] As a preferred embodiment of the present invention, in step S1, the method further comprises the following steps:

[0013] Step S11: according to the area to be studied, obtaining matching fish distribution point data from a preset database;

[0014] Step S12: according to the area to be studied, obtaining matching river network data and sub-basin data from preset hydrological data and map data sets;

[0015] Step S13: According to the area to be studied, matching river obstacle data is obtained from a preset river obstacle database.

[0016] As a preferred embodiment of the present invention, in step S11, the method further includes:

[0017] Sampling is carried out in the area to be studied to obtain fish distribution point data.

[0018] As a preferred embodiment of the present invention, in step S2, the method further comprises the following steps:

[0019] Step S21: obtaining the body length, caudal peduncle height and caudal fin area data of a preset fish;

[0020] Step S22: Calculate the diffusion distance of all fish in the watershed according to the preset body length, caudal peduncle height, caudal fin area of ​​the fish, river grade and diffusion time;

[0021] Step S23: classify the diffusion distances that fall within the preset quantile range.

[0022] As a preferred embodiment of the present invention, in step S2, the method further includes:

[0023] Among them, the preset fish data includes fish body length, caudal peduncle height and caudal fin area data, which are obtained by sampling preset fish specimens in the area to be studied.

[0024] As a preferred embodiment of the present invention, in step S3, the method further comprises the following steps:

[0025] Step S31: for the preset fish in the area to be studied, using the diffusion distance as the radius, buffering the fish distribution point data to generate potential distribution data of the preset fish;

[0026] Step S32: Correct the fish habitat range included in the potential distribution data according to the habits of the preset fish, and then combine the fish habitat range with the sub-basins in the watershed to generate accurate fish habitat distribution data.

[0027] As a preferred embodiment of the present invention, in step S4, the method further comprises the following steps:

[0028] Step S41: setting a given passing rate for each obstacle within the preset fish habitat range;

[0029] Step S42: Calculate the degree of fragmentation of the preset fish habitat.

[0030] As a preferred embodiment of the present invention, in step S4, the method further comprises the following steps:

[0031] Step S401: Calculate the comprehensive passing rate of all obstacles within the preset fish habitat:

[0032]

[0033] Among them, c ij is the comprehensive passing rate of all river obstacles between sub-basins i and j, which is used to evaluate the difficulty of the preset fish population entering sub-basin j from sub-basin i, p m is the fish passage rate for a given obstacle m, where M is the total number of obstacles in the river;

[0034] Step S402: Calculate the diffusion capacity of the preset fish species within the preset fish habitat:

[0035]

[0036] Among them, PD is the diffusion probability of the preset fish, d is the length of the main river between fish population i and population j;

[0037] Step S403: Calculate the connectivity of the preset fish:

[0038]

[0039] Among them, l i and l j is the total length of the river network in sub-basins i and j where a particular species inhabits, and L is the total length of rivers for all populations in the basin;

[0040] Step S404: Calculate the fish habitat fragmentation index within the preset fish habitat range:

[0041]

[0042] Among them, PCI o PCI is the original population connectivity state when no obstacles are built within the preset fish distribution range. F The fragmentation state when barriers are constructed within the species' distribution range.

[0043] As a preferred embodiment of the present invention, in step S404, the method further includes:

[0044] In calculating PCI o When , the fish passing rate of a given obstacle is set to 1;

[0045] In calculating PCI F When the passing rate of fish that cannot pass through obstacles is set to 0, the passing rate of fish that can pass through obstacles is set to 0.5 and / or 0.1;

[0046] The value of FHFI ranges from 0 to 100.

[0047] The present invention also provides a comprehensive evaluation system for the degree of habitat fragmentation of fish populations, comprising:

[0048] The data acquisition module is used to obtain the preset distribution data of fish in the area to be studied, including: river network data, sub-basin data and basin river obstacle data;

[0049] The diffusion calculation module is used to calculate the population diffusion capacity of each fish according to the preset fish data;

[0050] Range calculation module, used to reconstruct the range of fish habitat based on population dispersal capacity, preset distribution data and fish habit data;

[0051] The fragmentation calculation module is used to calculate the degree of habitat fragmentation of fish populations based on habitat range, population dispersal capacity and river obstacle data in the basin.

[0052] The above technical solution of the present invention has the following advantages compared with the prior art:

[0053] 1. Fully consider the impact of biological indicators and barrier construction on non-migratory fish in rivers, pay full attention to the migration distance and dispersal capacity of fish in rivers, and comprehensively consider the range of fish habitats, so as to construct a comprehensive fragmentation evaluation method for habitats of specific species.

[0054] 2. By calculating the population dispersal capacity of fish, combined with factors such as river grade and dispersal time, the contribution of each fish species to river connectivity can be quantified, which helps to understand the migration capacity of different fish species in rivers, thereby more accurately assessing their habitat range and degree of fragmentation.

[0055] 3. Reconstructing the range of fish habitats based on the dispersal capacity and habits of fish (such as migration type) can more accurately determine areas where fish may appear, which helps guide ecosystem protection and restoration work, especially for fish of different migratory types; then, based on the location and pass rate of obstacles in the river network, combined with the dispersal capacity and habitat range of fish, calculating the degree of habitat fragmentation can help identify bottlenecks and key areas in the river and provide an important reference for protecting and restoring the habitat. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0057] Figure 1 It is a flow chart of a comprehensive evaluation method for the degree of habitat fragmentation of fish populations provided by an embodiment of the present invention.

[0058] Figure 2 It is a flow chart of a data acquisition method provided by an embodiment of the present invention.

[0059] Figure 3 It is a flow chart of a data processing method provided by an embodiment of the present invention.

[0060] Figure 4 It is a flow chart of a method for reconstructing fish habitat range provided by an embodiment of the present invention.

[0061] Figure 5 This is a first flow chart of a method for calculating the degree of fragmentation of fish habitats provided by an embodiment of the present invention.

[0062] Figure 6 This is a second flow chart of the method for calculating the degree of fish habitat fragmentation provided by an embodiment of the present invention.

[0063] Figure 7 is a schematic diagram of a fish habitat distribution map provided by an embodiment of the present invention; wherein, Figure 7 The data at point A are the distribution points of giant bream in the Mekong River Basin. Figure 7 The light-colored area in B is the actual distribution habitat of the giant croaker. Figure 7 The data at point C are the distribution points of river obstacles in the Mekong River Basin.

[0064] Figure 8 It is a schematic diagram of measuring and calculating the caudal peduncle height and caudal fin area of ​​a sampled Schizothorax glabrata specimen provided by an embodiment of the present invention.

[0065] Fig. 9 It is a schematic diagram of module connections of a comprehensive evaluation system for the degree of habitat fragmentation of fish populations provided by an embodiment of the present invention.

[0066] Description of the Figures in the Specification:

[0067] 100. Data acquisition module, 101. Diffusion calculation module, 102. Range calculation module, 103. Fragmentation calculation module. DETAILED DESCRIPTION

[0068] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0069] refer to Figure 1 As shown, in some embodiments, a comprehensive evaluation method for the degree of habitat fragmentation of fish populations is provided, and the method comprises the following steps:

[0070] Step S1: Obtain preset distribution data of fish in the area to be studied, including: river network data, sub-basin data and basin river obstacle data.

[0071] Among them, step S1 is data acquisition: to obtain the distribution data of various fish in the area to be studied, the river network data of the basin in the study area, the sub-basin data and the basin river obstacle data; the specific fish species are selected by the researchers according to actual needs.

[0072] Specifically, refer to Figure 2 As shown, in step S1, the method further includes the following steps:

[0073] Step S11: According to the area to be studied, the matching fish distribution point data is obtained from the preset database.

[0074] In the actual implementation process, for the area to be studied, information is searched from public journal literature databases and online databases to obtain fish distribution point data.

[0075] In some embodiments, fish distribution point data can also be obtained by sampling from the area to be studied. The specific method of obtaining the fish distribution point data is selected by the researchers based on actual needs and costs.

[0076] Step S12: According to the area to be studied, the matching river network data and sub-basin data are obtained from the preset hydrological data and map data set.

[0077] In the actual implementation process, the river network data and sub-basin data reference are obtained from the HydroSHEDS (hydrological data and maps based on multi-scale shuttle elevation derivatives) dataset. The hydrological data and maps based on multi-scale shuttle elevation derivatives are digital representations of hydrological features, related features and their spatial relationships. This data source contains rivers, lakes, streams, water bodies and watersheds, as well as information about the surrounding landscape and climate conditions. The hydrological data are distributed all over the world and can be downloaded in geographic database or shapefile format.

[0078] In some embodiments, river network data and sub-basin data of the river basin can be obtained from public journal literature databases (for example: high-resolution global river map MERIT Hydro) depending on the research area. The specific method of obtaining river network data and sub-basin data is selected by researchers based on actual needs and costs.

[0079] Step S13: According to the area to be studied, matching river obstacle data is obtained from a preset river obstacle database.

[0080] In the actual implementation process, the river obstacle data reference is obtained from the Global River Obstructions Database, which is a project aimed at collecting and integrating river obstacle data worldwide. These obstacles mainly include man-made structures such as dams, weirs, gates, and weirs. Their presence in rivers significantly affects the natural flow of water, the health of river ecosystems, and the migration paths of organisms. The establishment of this database is to: provide researchers with detailed information on global river obstacles to study their impact on river ecosystems, biodiversity, and fish migration patterns; provide reference for government agencies, environmental organizations, and relevant stakeholders to develop more effective river management and protection strategies and achieve sustainable development of river ecosystems.

[0081] In some embodiments, river obstacle data can be obtained by selecting different open source databases according to the research area (for example: Global Reservoir Dam Engineering Database GRanD), or obtained through field surveys. The specific method of obtaining river obstacle data is selected by researchers based on actual needs and costs.

[0082] Step S2: Calculate the population diffusion capacity of each fish species based on the preset fish data.

[0083] Specifically, refer to Figure 3 As shown, in step S2, the method further includes the following steps:

[0084] Step S21: obtaining the body length, caudal peduncle height and caudal fin area data of a preset fish.

[0085] In the actual implementation process, the body length, caudal peduncle height and caudal fin area data of the preset fish are obtained through the online open source database FishBase. The online open source database FishBase is a comprehensive online open source database that aims to provide detailed information on all fish species in the world. Since its establishment in the early 1990s, it has become an important resource for fish research, fishery management, conservation and education. FishBase covers data from basic biology, ecology, conservation status to fish distribution, providing a valuable source of information for researchers, policy makers, educators and the public. FishBase includes detailed information on tens of thousands of fish species in the world, including marine fish, freshwater fish and some extremely rare species. For each species, FishBase provides data on description, classification, habitat, distribution, biological information, nutritional habits, utilization and conservation.

[0086] In some embodiments, data such as the body length and tail fin length-to-width ratio of fish species can be obtained by directly measuring and sampling fish specimens. The specific method of obtaining the preset fish data is selected by the researchers based on actual needs and costs.

[0087] Step S22: Calculate the diffusion distance of all fish in the watershed based on the body length, caudal peduncle height, caudal fin area of ​​the preset fish, river grade and diffusion time.

[0088] Step S23: classify the diffusion distances that fall within the preset quantile range.

[0089] In the actual implementation process, the 'fishmove' R package was used to classify the dispersal distances of all fish in the basin according to the body length, caudal peduncle height, caudal fin area, river grade and dispersal time of the studied fish species by setting the quantiles to 0%, 14.3%, 28.6%, 42.9%, 57.1%, 71.4%, 85.7% and 100%. The dispersal distances falling within the quantile range were then divided into seven categories, ranging from 0.3 to 0.9, representing the dispersal probability of fish from low to high; among them, the time parameter of dispersal was 10 years to estimate the long-term population-level dispersal.

[0090] In some embodiments, the diffusion probability of fish can also be obtained by directly dividing the fish according to the experience of experts.

[0091] Step S3: Reconstruct the fish habitat range based on the population diffusion capacity, preset distribution data and fish habit data.

[0092] Specifically, refer to Figure 4 As shown, in step S3, the method further includes the following steps:

[0093] Step S31: for the preset fish species in the area to be studied, the diffusion distance is used as the radius, the fish species distribution point data is buffered, and a potential distribution map of the preset fish species is generated.

[0094] Step S32: Correct the fish habitat range of the potential distribution map according to the habits (migratory type) of the species described in journal literature, and intersect the fish distribution range with the sub-basins within the watershed to obtain an accurate fish habitat distribution (sub-basin) map.

[0095] Step S4: Calculate the degree of habitat fragmentation of fish populations based on habitat range, population dispersal capacity and river obstacle data in the basin.

[0096] Specifically, refer to Figure 5 As shown, in step S4, the method further includes the following steps:

[0097] Step S41: setting a given pass rate for each obstacle within the preset fish habitat range.

[0098] Step S42: Calculate the degree of fragmentation of the preset fish habitat.

[0099] In the actual implementation process, within a watershed, a certain fish species usually exists in multiple sub-basins, and the movement of a population from a sub-basin to other sub-basins for individual exchange between populations is the basis for maintaining the population size. The construction of river obstacles will hinder the entry of fish from their sub-basins into adjacent sub-basins, directly affecting the exchange of fish populations and leading to population fragmentation. Therefore, this application calculates the original connectivity of the fish population and the fragmented connectivity affected by the obstacles, and obtains the fragmentation index of the population habitat by calculating the percentage of change.

[0100] Therefore, in some embodiments, reference Figure 6 As shown, the method further comprises the following steps:

[0101] Step S401: Calculate the comprehensive passing rate of all obstacles within the preset fish habitat:

[0102]

[0103] Among them, c ij is the comprehensive passing rate of all river obstacles between sub-basins i and j, which is used to evaluate the difficulty of the preset fish population entering sub-basin j from sub-basin i, p m is the fish passage rate for a given obstacle m, where M is the total number of obstacles in the river.

[0104] Step S402: Calculate the diffusion capacity of the preset fish species within the preset fish habitat:

[0105]

[0106] Among them, PD is the diffusion probability of the preset fish, and d is the length of the main river between the fish.

[0107] Step S403: Calculate the connectivity of the preset fish:

[0108]

[0109] Among them, l i and l j is the total length of the river network in sub-basins i and j where a specific species inhabits, L is the total length of the river network for all populations in the basin; PCI is the connectivity status of fish populations, which is divided into PCI o With PCI F .

[0110] Step S404: Calculate the fish habitat fragmentation index within the preset fish habitat range:

[0111]

[0112] Among them, PCI o PCI is the original population connectivity state when no obstacles are built within the preset fish distribution range. F The fragmentation state when constructing barriers within the species distribution range; in calculating PCI o When calculating PCI, the fish passing rate of a given obstacle is set to 1; F , the passing rate of fish that cannot pass through obstacles is set to 0, and the passing rate of fish that can pass through obstacles is set to 0.5 and / or 0.1.

[0113] When fish populations are located in sub-basins without obstacles, or obstacles are only located at the edge of the fish distribution range and do not affect internal diffusion, the FHFI value will be 0; conversely, if the habitat is severely fragmented by obstacles, preventing fish from moving freely from one sub-basin to another, the FHFI value will be close to 100.

[0114] Illustratively, in some embodiments, the embodiments of the present invention provide a comprehensive evaluation method for the degree of habitat fragmentation of fish populations, which is used for the comprehensive evaluation of the degree of fish habitat fragmentation at the basin scale. The specific steps are as follows: (1) This example is applied to the Mekong River Basin. First, the information in the existing public journal literature database and network database is searched to obtain 1032 fish species, totaling 160,000 distribution point data. Through the HydroSHEDS data set, the river network data of the Mekong River Basin and 1130 unit data of the Mekong River sub-basin (level 8) are extracted, and the basin obstacle data is extracted from the Mekong River Obstacle Database (GROD).

[0115] (2) The morphological data of fish in the basin were obtained through the online open source database FishBase. The 'fishmove' R package was used to estimate the long-term population-level diffusion based on the body length, caudal peduncle height, caudal fin area, river level and diffusion time of the studied fish species. The time parameter was 10 years to estimate the long-term population-level diffusion. The diffusion distances of all fish in the basin were classified by setting the quantiles to 0%, 14.3%, 28.6%, 42.9%, 57.1%, 71.4%, 85.7% and 100%. The diffusion distances falling within the quantile range were then divided into seven categories ranging from 0.3 to 0.9, representing the diffusion probability of fish from low to high. Taking the mullet (scientific name: Bagarius bagarius) as an example, the maximum diffusion distance of its population in ten years was calculated to be 756,440 kilometers, and its diffusion capacity was between 85.7% and 100% among all fish. Therefore, its PD was assigned a value of 0.9.

[0116] (3) Using the calculated species diffusion distance as the radius, the obtained distribution points of the mullet were buffered to generate a potential distribution map of the mullet. According to the description in the journal literature that the species is a river migratory type and is mainly distributed in the main river channel, the fish habitat range of the potential distribution map was corrected, and the fish distribution range was intersected with the sub-basins in the basin to obtain an accurate fish habitat distribution map. Figure 7 shown.

[0117] (4) A given pass rate is set for each obstacle within the fish habitat. The value of the dam is set to 0. For obstacles that can be passed, such as weirs, the pass rate is set to 0.5. The degree of habitat fragmentation is calculated by the above formula to be 41.37. It is concluded that the habitat of the giant mullet is severely fragmented due to the construction of river obstacles.

[0118] For example, in some embodiments, the present invention provides a comprehensive evaluation method for the degree of habitat fragmentation of fish populations, which is used for the comprehensive evaluation of the degree of fish habitat fragmentation at the watershed scale. The specific steps are as follows:

[0119] (1) This example is applied to the Lancang River Basin to evaluate the degree of habitat fragmentation of the important economic fish species in the Lancang River, Schizothorax lissolabiatus. First, through years of field sampling data, combined with the information in the existing public journal literature database and online database, a total of 243 distribution point data of Schizothorax lissolabiatus in the Lancang River Basin were obtained. The river network data of the Lancang River Basin and 100 sub-basin (level 8) unit data were extracted through the HydroSHEDS dataset. 1052 watershed obstacle data were extracted from the Lancang River river obstacle database.

[0120] (2) Based on the sampling data, the body length of each Lancang schizothorax was obtained. The caudal peduncle height and caudal fin area were measured and calculated using ImageJ software. Figure 8 As shown. Using the 'fishmove' R package, the body length, tail fin height to tail fin area ratio, river level and diffusion time of the studied fish species were used. The time parameter was 10 years to estimate the long-term population level diffusion. The maximum diffusion distance of its population in ten years was calculated to be 26,199 kilometers, and its diffusion capacity was between 57.1% and 71.4% among all fish in the basin. Therefore, its PD was assigned a value of 0.7.

[0121] (3) Using the calculated species dispersal distance as the radius, the distribution points of the Lancang schizothorax obtained in the first step were buffered to generate its potential distribution map. According to the description in the journal literature that the species is a river-dwelling type and is distributed in both the main stream and tributaries, the fish habitat range of the potential distribution map was corrected, and the fish distribution range was intersected with the sub-basins within the basin to obtain an accurate fish habitat distribution map;

[0122] (4) A given pass rate is set for each obstacle within the fish habitat, and the value of the dam is set to 0. For obstacles that can be passed, such as weirs and sluice gates, the pass rate is set to 0.5, and the degree of habitat fragmentation is calculated by the above formula to be 26.36. It is concluded that the habitat of the Lancang River schizothorax is moderately fragmented due to the construction of river obstacles.

[0123] refer to Fig. 9 As shown, in some embodiments, the present invention further provides a comprehensive evaluation system for the degree of habitat fragmentation of fish populations, including:

[0124] The data acquisition module 100 is used to obtain the preset distribution data of fish in the area to be studied, including: river network data, sub-basin data and basin river obstacle data;

[0125] The diffusion calculation module 101 is used to calculate the population diffusion capacity of each fish according to the preset fish data;

[0126] Range calculation module 102, used to reconstruct the range of fish habitat according to the population diffusion capacity, preset distribution data and fish habit data;

[0127] The fragmentation calculation module 103 is used to calculate the degree of habitat fragmentation of fish populations based on the habitat range, population dispersal capacity and river obstacle data in the basin.

[0128] In some embodiments, the present invention further provides a computer medium having a computer program stored thereon, wherein the computer program is executed by a processor to implement the comprehensive evaluation method for the degree of habitat fragmentation of fish populations.

[0129] In some embodiments, the present invention also provides a computer, comprising the computer medium described above.

[0130] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0131] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A comprehensive evaluation method for the degree of habitat fragmentation of fish populations, characterized in that: The following steps are involved: Step S1: obtaining preset distribution data of fish in the area to be studied, including: river network data, sub-basin data and basin river obstacle data; Step S2: Calculate the population diffusion capacity of each fish species according to the preset fish data; Step S3: reconstructing the fish habitat range according to the population diffusion capacity, preset distribution data and fish habit data; Step S4: Calculate the degree of habitat fragmentation of fish populations based on habitat range, population dispersal capacity and river obstacle data in the basin; The following steps are also included: Step S401: Calculate the comprehensive passing rate of all obstacles within the preset fish habitat: Among them, c ij is the comprehensive passing rate of all river obstacles between sub-basins i and j, which is used to evaluate the difficulty of the preset fish population entering sub-basin j from sub-basin i, p m is the fish passage rate for a given obstacle m, where M is the total number of obstacles in the river; Step S402: Calculate the diffusion capacity of the preset fish species within the preset fish habitat: Among them, PD is the diffusion probability of the preset fish, d ij is the length of the main river channel between fish populations ij; Step S403: Calculate the connectivity of the preset fish: Among them, l i and l j is the total length of the river network in sub-basins i and j where a particular species inhabits, and L is the total length of all rivers in the basin; Step S404: Calculate the fish habitat fragmentation index within the preset fish habitat range: Among them, PCI o PCI is the original population connectivity state when no obstacles are built within the preset fish distribution range. F The fragmentation state when barriers are constructed within the species' distribution range.

2. A comprehensive evaluation method for the degree of habitat fragmentation of fish populations according to claim 1, characterized in that: In step S1, the method further comprises the following steps: Step S11: according to the area to be studied, obtaining matching fish distribution point data from a preset database; Step S12: according to the area to be studied, obtaining matching river network data and sub-basin data from preset hydrological data and map data sets; Step S13: According to the area to be studied, matching river obstacle data is obtained from a preset river obstacle database.

3. A comprehensive evaluation method for the degree of habitat fragmentation of fish populations according to claim 2, characterized in that: In step S11, the method further includes: Sampling is carried out in the area to be studied to obtain fish distribution point data.

4. A comprehensive evaluation method for the degree of habitat fragmentation of fish populations according to claim 2, characterized in that: In step S2, the method further comprises the following steps: Step S21: obtaining the body length, caudal peduncle height and caudal fin area data of a preset fish; Step S22: Calculate the diffusion distance of all fish species in the watershed according to the preset body length, caudal peduncle height, caudal fin area of ​​the fish, river grade and diffusion time; Step S23: classify the diffusion distances that fall within the preset quantile range.

5. A comprehensive evaluation method for the degree of habitat fragmentation of fish populations according to claim 3, characterized in that: In step S2, the method further include: Among them, the preset fish data includes fish body length, caudal peduncle height and caudal fin area data, which are obtained by sampling preset fish specimens in the area to be studied.

6. A comprehensive evaluation method for the degree of habitat fragmentation of fish populations according to claim 4, characterized in that: In step S3, the method further comprises the following steps: Step S31: for the preset fish in the area to be studied, using the diffusion distance as the radius, buffering the fish distribution point data to generate potential distribution data of the preset fish; Step S32: Correct the fish habitat range included in the potential distribution data according to the habits of the preset fish, and then combine the fish habitat range with the sub-basins in the watershed to generate accurate fish habitat distribution data.

7. A comprehensive evaluation method for the degree of habitat fragmentation of fish populations according to claim 1, characterized in that: In step S404, the method further includes: In calculating PCI o When , the fish passing rate of a given obstacle is set to 1; In calculating PCI F When the fish pass rate of the impassable obstacles is set to 0, the fish pass rate of the impassable obstacles is set to 0.5 (moderate pass rate) and / or 0.1 (low pass rate) according to the degree of patency of the given river obstacles; The value of FHFI ranges from 0 to 100.

8. A comprehensive evaluation system for the degree of habitat fragmentation of fish populations, characterized in that: A comprehensive evaluation method for the degree of habitat fragmentation of fish populations as described in any one of claims 1 to 7 is implemented, comprising: The data acquisition module is used to obtain the preset distribution data of fish in the area to be studied, including: river network data, sub-basin data and basin river obstacle data; The diffusion calculation module is used to calculate the population diffusion capacity of each fish according to the preset fish data; Range calculation module, used to reconstruct the range of fish habitat based on population dispersal capacity, preset distribution data and fish habit data; The fragmentation calculation module is used to calculate the degree of habitat fragmentation of fish populations based on habitat range, population dispersal capacity and river obstacle data in the basin.

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