A method for assessing river ecosystem stability based on the ratio of generalist to specialized species

Abstract

The application discloses a kind of river ecosystem stability evaluation method based on the ratio of generalization species and specialization species.The present application relates to the technical field of river ecosystem stability evaluation, solve the problem of insufficient sensitivity of existing evaluation methods to the dynamic response of river system stability.The present application sets sampling points in different river sections according to the actual situation of the river, collects benthic microbial samples on gravel, sandy and sediment in the target river section, and measures the environmental indicators of each sampling point;high-throughput sequencing is performed on the benthic microbial samples, and the generalization species and specialization species are identified in combination with Levins niche breadth;the generalization species and specialization species of benthic microorganisms are identified and quantified, the threshold relationship between the ratio of generalization species and specialization species and the stability of river ecosystem is determined, an evaluation system for the stability of river ecosystem based on the ratio of generalization species and specialization species is constructed, and the stability of aquatic ecosystem is evaluated and the comprehensive management of river basin and ecosystem construction are promoted.

Description

Technical Field

[0001] The present invention relates to the technical field of river ecosystem stability assessment, and in particular to a method for assessing river ecosystem stability based on the ratio of generalized species to specialized species. Background Art

[0002] Riverine ecosystems, at the core of land-water interactions, play a crucial role in carbon and nitrogen cycling, maintaining biodiversity, and providing ecological services. Benthic microorganisms contribute to the primary productivity of riverine ecosystems, and their stability directly impacts the ecological security of the watershed. Riverine ecosystem stability is defined as the system's ability to maintain its structure and function despite external disturbances. Currently, assessment methods rely primarily on functional and structural indicators, both of which suffer from the drawback of failing to accurately reflect the heterogeneity of continuous river habitats. Furthermore, existing indicators are often based on a single functional parameter and are unable to fully characterize the functional collaboration and competition between biological communities, resulting in insufficient sensitivity to the dynamic responses of riverine system stability. Therefore, it is necessary to propose a riverine ecosystem stability assessment method based on the ratio of generalist to specialized species to address these issues. Summary of the Invention

[0003] The purpose of the present invention is to provide an assessment method for river ecosystem stability based on the ratio of generalized species to specialized species, so as to solve the problem that existing assessment methods are insufficiently sensitive to the dynamic response of river system stability.

[0004] The present invention provides a method for evaluating the stability of a river ecosystem based on the ratio of generalized species to specialized species, comprising:

[0005] Step 1: Set up sampling points in different river sections according to the actual situation of the river, collect benthic microbial samples on gravel, sand and bottom mud in the target river section, and measure the environmental indicators of each sampling point;

[0006] Step 2: High-throughput sequencing of benthic microbial samples was performed, and Levins niche breadth was used to identify generalist and specialized species.

[0007] Step three: Identify and quantify the generalist and specialized species of benthic microorganisms, determine the threshold relationship between the ratio of generalist and specialized species and the stability of river ecosystems, and construct an evaluation system for the stability of river ecosystems based on the ratio of generalist and specialized species.

[0008] Furthermore, the step 1 includes:

[0009] Using ArcGIS 10.8 The software combines DEM elevation data to divide the target river into sampling points and river sections;

[0010] At least 3 to 5 sampling sections are set up in each river section. A laser rangefinder is used to continuously measure 3 sections with a spacing of 50m. The average value is taken as the representative river width at that point. The total number of sampling points n satisfies:

[0011] , where L is the total length of the river, in meters; W is the average width of the river section, in meters;

[0012] The sediment type, vegetation cover, water quality indicators, and GPS positioning information of the sampling points were measured and recorded for habitat delineation. Sediment type was identified in situ according to the Wentworth classification method. Samples from the edge and center of the river channel were selected. Sterile brushes and porous adsorption brushes were used to collect microorganisms from each type of sediment in a standardized manner. Three biological replicates were collected from each type of sediment and placed in a portable incubator at 4°C. All sampling was completed on the same hydrological day.

[0013] Furthermore, the step 2 includes:

[0014] High-throughput sequencing technology is used to perform amplicon or metagenomic sequencing on benthic microbial samples, and the microbial community is compared with the database for species annotation. According to the habitat of different river sections, the relative abundance P of a species i in a specific habitat is calculated. i , the calculation formula is as follows:

[0015]

[0016] Where s is the number of different habitats, and N is the number of species that depend on the habitat;

[0017] According to Levins' niche theory, the niche width B of each species was calculated, and generalized species and specialized species were identified. The calculation formula is as follows:

[0018]

[0019] Where s is the number of different habitats, P i is the relative abundance of species i in a specific habitat.

[0020] Furthermore, B = 0.6 ~ 1 is a generalized species, and B = 0.1 ~ 0.3 is a specialized species.

[0021] Furthermore, the step three includes:

[0022] The dynamic relationship between the ratio of generalist species to specialized species, K, and the stability of the river ecosystem was constructed using the following calculation formula:

[0023]

[0024] Among them, N g is the number of generalized species, Ns To specialize the number of species.

[0025] The application has the following beneficial effects: the river ecosystem stability evaluation method based on the ratio of generalized species and specialized species of the application innovatively realizes the evaluation of the water ecological system stability and promotes the comprehensive management of the basin and the construction of the ecological system by constructing the relationship between the indicator species ratio and the river ecosystem stability threshold based on the dynamic ratio of the generalized species and the specialized species. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the application, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0027] Figure 1 The figure is a niche diagram of generalized species and specialized species.

[0028] Figure 2 The figure is a dynamic relationship diagram of the ratio of generalized species and specialized species and the river ecosystem stability. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the application more clear, the technical solutions of the application will be clearly and completely described in combination with the specific embodiments of the application and the corresponding drawings. Obviously, the described embodiments are only some of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the application. The technical solutions provided by each embodiment of the application will be described in detail below in combination with the drawings.

[0030] Please refer to Figure 1 The embodiment of the application provides a river ecosystem stability evaluation method based on the ratio of generalized species and specialized species. First, the sampling points of each river section of the target river are determined, the benthic microbial samples are obtained in the sampling points of different substrates, and different habitat information is recorded. According to the Levins niche theory, the generalized and specialized species are identified, and the number ratio between them is calculated. Finally, the dynamic relationship between the ratio of generalized species and specialized species and the river ecosystem stability is constructed, forming a river ecosystem stability evaluation method.

[0031] The river ecosystem stability evaluation method based on the ratio of generalized species and specialized species includes three steps:

[0032] Step 1: According to the actual situation of the river, sampling points are set in different river sections, benthic microbial samples on gravel, sandy and sediment in the target river section are collected, and the environmental indicators of each sampling point are measured.

[0033] Sampling points should be evenly distributed in all sections of the target river, the distance between adjacent sampling points should be more than 5 times the width of the river, and microorganisms on each bottom type should be collected to ensure the accuracy of the assessment of the stability of the entire river ecosystem.

[0034] Specifically, using ArcGIS 10.8 The software combines 10m resolution satellite images and DEM elevation data to divide the target river into river sections for each sampling point.

[0035] At least 3 to 5 sampling sections were set up in each river section. Leica DISTOD8 laser rangefinder was used to continuously measure 3 sections with a spacing of 50 m. The average value was taken as the representative river width at that point. The total number of sampling points n met the following requirements:

[0036] , where L is the total length of the river, in meters; W is the average width of the river section, in meters;

[0037] Record the bottom sediment type and GPS location information of the sampling point, ArcGIS 10.8 Vegetation cover was calculated using remote sensing imagery, and water quality indicators such as dissolved oxygen, temperature, and pH were measured with a YSI portable water quality monitor. Based on these indicators, the Bray-Curtis dissimilarity coefficient in PRIMER 7.0 was used to divide the river section into distinct habitats, with a calculated habitat clustering threshold of ≤0.3. Three types of sediment were identified in situ using the Wentworth classification system, as shown in Table 1. Gravel, sand, and sediment samples were collected from the edge and center of the channel at each section. Microorganisms from each sediment type were collected using a sterile brush and a 0.45 μm porous adsorption brush in a standardized manner. The samples were placed in 5 ml centrifuge tubes, wrapped with parafilm, and labeled with sample information. Three biological replicates were collected for each sediment type and sampling depth, with each replicate group placed in 50 ml centrifuge tubes. Separate centrifuge tubes containing samples from different habitats were sealed in plastic bags and placed in a portable incubator at 4°C for rapid transfer to the laboratory. All sampling was performed on the same hydrological day, with rainfall <5 mm and flow fluctuation <10%.

[0038] Table 1 Classification of substrate types

[0039]

[0040] Step 2: Perform high-throughput sequencing on benthic microbial samples and identify generalized and specialized species based on Levins niche breadth.

[0041] Specifically, the metagenomic sample of benthic microorganisms is subjected to amplicon or metagenomic sequencing by using high-throughput sequencing technology, and the microbial community is compared with a database for species annotation. The present embodiment uses the high-throughput sequencing platform Illumina NovaSeq6000 to perform amplicon or metagenomic sequencing on the microbial sample, compares the microbial community with the databases Silva, Unite and RDP, and performs species annotation with a confidence threshold of 97%. i , the calculation formula is as follows:

[0042]

[0043] wherein s is the number of different habitats, and N is the number of species dependent on the habitat.

[0044] According to the Levins niche theory, the niche width B of each species is calculated, and the generalist species and specialist species are identified, B = 0.6-1 is a generalist species, B = 0.1-0.3 is a specialist species, and the transitional species with B value between 0.3-0.6 is excluded. The calculation formula is as follows:

[0045]

[0046] wherein s is the number of different habitats, and P i is the relative abundance of species i in a specific habitat.

[0047] Step three, identify and quantify the generalist species and specialist species of benthic microorganisms, determine the threshold relationship between the proportion of generalist species and specialist species and the stability of river ecosystem, and construct an evaluation system of river ecosystem stability based on the proportion of generalist species and specialist species.

[0048] Specifically, as shown in Figure 2 , the dynamic relationship between the proportion of generalist species and specialist species K and the stability of river ecosystem is constructed, and the calculation formula is as follows:

[0049]

[0050] wherein N g is the number of generalist species, and N s is the number of specialist species.

[0051] In summary, based on the generalized species and specialized species classification system of the niche theory, the application breaks through the limitation of the traditional method, innovatively proposes an evaluation system based on the niche ratio of generalized species and specialized species, and realizes the sensitive response to the stability change of the river ecosystem. The application aims to dynamically evaluate the stability of the river ecosystem, quantify the response threshold of microorganisms to stress, accurately identify the river ecological fragile area and degradation node, and provide a scientific basis for the stable recovery and sustainable management of the river water ecology under environmental pressure.

[0052] The above-mentioned embodiments of the application do not constitute a limitation on the protection scope of the application.

Claims

1. A method for evaluating river ecosystem stability based on the ratio of generalized species to specialized species, characterized by: include: Step 1: Set up sampling points in different river sections according to the actual situation of the river, collect benthic microbial samples on gravel, sand and bottom mud in the target river section, and measure the environmental indicators of each sampling point; The step one comprises: Using ArcGIS 10.8 The software combines DEM elevation data to divide the target river into sampling points and river sections; At least 3 to 5 sampling sections are set up in each river section. A laser rangefinder is used to continuously measure 3 sections with a spacing of 50m. The average value is taken as the representative river width at that point. The total number of sampling points n satisfies: , where L is the total length of the river, in meters; W is the average width of the river section, in meters; Substrate type, vegetation cover, water quality indicators, and GPS location information were measured and recorded at the sampling points for habitat delineation. Substrate type was identified in situ using the Wentworth classification method. Samples were taken from the edge and center of the river channel. Sterile and porous adsorbent brushes were used to collect microorganisms from each type of substrate in a standardized manner. Three biological replicates were collected from each type of substrate and placed in a portable incubator at 4°C. All sampling was completed on the same hydrological day. Step 2: Perform high-throughput sequencing on benthic microbial samples and identify generalist and specialized species based on Levins niche breadth. The second step includes: High-throughput sequencing technology is used to perform amplicon or metagenomic sequencing on benthic microbial samples, and the microbial community is compared with the database for species annotation. According to the habitat of different river sections, the relative abundance P of a species i in a specific habitat is calculated. i , the calculation formula is as follows: Where s is the number of different habitats, and N is the number of species that depend on the habitat; According to Levins' niche theory, the niche width B of each species was calculated, and generalized species and specialized species were identified. The calculation formula is as follows: Where s is the number of different habitats, P i is the relative abundance of species i in a specific habitat; Step three: Identify and quantify the generalist and specialized species of benthic microorganisms, determine the threshold relationship between the ratio of generalist to specialized species and river ecosystem stability, and construct an evaluation system for river ecosystem stability based on the ratio of generalist to specialized species; The step three includes: The dynamic relationship between the ratio of generalist species to specialized species, K, and the stability of the river ecosystem was constructed using the following calculation formula: Among them, N g is the number of generalized species, N s The number of specialized species.

2. The method for evaluating river ecosystem stability based on the ratio of generalized species to specialized species according to claim 1, wherein: B=0.6~1 is a generalized species, and B=0.1~0.3 is a specialized species.

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