Method for comprehensively evaluating dynamic change of biological diversity of ecological system at high dimension

Abstract

The invention relates to a method for comprehensively evaluating dynamic change of biological diversity of an ecological system in a high dimension, which comprises the following steps of: randomly selecting a plurality of experimental areas in a target ecological system, randomly collecting a plurality of parallel samples in each experimental area, and extracting historical biological group monitoring data of a local ecological monitoring station from a database of the local ecological monitoring station; and finally, analyzing and calculating a biological diversity comprehensive change index of the target class group from six key dimensions including category richness, function richness, phylogenetic richness, inter-community category dissimilarity, function dissimilarity and phylogenetic dissimilarity. According to the method, an integral measurement standard is provided for biodiversity changes, evaluation errors caused by different selection of diversity indexes are effectively solved, and a scientific basis is provided for transverse management of global protection targets.

Description

Technical Field

[0001] The present invention relates to a method for high-dimensional comprehensive assessment of dynamic changes in ecosystem biodiversity, belonging to the technical field of ecosystem diversity assessment. Background Art

[0002] Biodiversity refers to the ecological complex formed by organisms and the environment and the sum of various ecological processes related to it, including diversity at three levels: species, ecosystem, and genetics, involving the number, space, distribution, composition structure, and abundance of organisms. Biodiversity is not only a key factor in maintaining the balance and stability of ecosystems, but also an indispensable element in supporting human livelihoods and improving the quality of life. Therefore, it is vital to protect and promote biodiversity.

[0003] However, current assessments of ecosystem biodiversity are mostly based on species taxonomy. Due to the differences in the environment between different regions, the selection of indicators and quantification methods are complex and varied. Most biodiversity indices only select species diversity for calculation and assessment, ignoring the functional and phylogenetic diversity of species. The functional and phylogenetic diversity of species determines how organisms affect the function and stability of ecosystems, and is crucial for conservation. At the same time, the mismatch between changes in taxonomic, functional and phylogenetic differences among biological groups worldwide highlights the risks of evaluating based on changes in a single indicator as a substitute for changes in other indicators. Summary of the invention

[0004] The present invention proposes a high-dimensional comprehensive method for evaluating the dynamic changes of ecosystem biodiversity. Its purpose is to propose a high-dimensional evaluation method from the time dimension to address the complex problems of indicator selection and quantification methods for measuring changes in ecosystem biodiversity. The method evaluates changes in biodiversity on a time scale based on six key dimensions, which can effectively address the one-sidedness of current biodiversity assessments. The focus of the assessment is expanded from simple species loss to comprehensive changes in biodiversity caused by interactions between collaborative human activities, providing potential for determining priorities and information for adaptive management and global conservation goals.

[0005] The technical solution of the present invention is a method for high-dimensional comprehensive assessment of dynamic changes in ecosystem biodiversity, comprising the following steps: (1) Randomly select several experimental areas in the target ecosystem and randomly collect several parallel samples in each experimental area; (2) Extract the historical biological community monitoring data of the area from the database of the local ecological monitoring station, and analyze and calculate the biodiversity and historical biodiversity of the target community from six dimensions: species richness, functional richness, phylogenetic richness, species dissimilarity among communities, functional dissimilarity, and phylogenetic dissimilarity; (3) Calculate the comprehensive biodiversity change index.

[0006] The species richness calculation formula is: (1) in, : Number of species observed; : OTUs with only one sequence; : OTUs with only two sequences.

[0007] The function richness calculation formula is: (2) in, : The niche space occupied by species in community i; : Absolute value range of trait c.

[0008] The phylogenetic richness is the total length of the branches connecting all species on the phylogenetic tree, and the calculation formula is:

[0009] Where Li is the length of each branch on the phylogenetic tree; n is the number of species included in the calculation.

[0010] The calculation formula of species dissimilarity between the communities is:

[0011] in, : The number of species in the intersection of community A and community B; : The number of species in the union of communities A and B.

[0012] The functional dissimilarity calculation formula is: (5) in, : observed functional richness, : expected functional richness, obtained by random sampling or model prediction; : Maximum feature richness.

[0013] The phylogenetic dissimilarity calculation formula is: (6) Where n is the number of nodes or branches on the phylogenetic tree, : the length of the ith node or branch, : The number of samples under this node or branch.

[0014] The step (3) of calculating the comprehensive biodiversity change index comprises the following steps: 1) Based on the historical and current values ​​of the six diversity indices, the temporal changes of each diversity index are calculated using the following formula: (7) in: is the current value of the diversity index, is the historical value of the diversity index.

[0015] The score was calculated based on the δDI value of each sample in all experimental areas: if the δDI was 1, the score was 0; if the δDI was higher than the median of all values ​​less than 1 and lower than the median of all values ​​greater than 1, the score was 1; if the δDI was lower than the median of all values ​​less than 1 or higher than the median of all values ​​greater than 1, the score was 2.

[0016] 2) Summarize the scores of the six local indexes δDI to obtain the comprehensive change index of biodiversity. The calculation formula is as follows: (8) Beneficial effects of the present invention: (1) Starting from the three aspects of species, function and phylogeny, the present invention selects six indicators, namely species richness and species dissimilarity between communities, functional richness and functional dissimilarity, phylogenetic richness and phylogenetic dissimilarity. While simplifying the calculation type, it can fully describe the diversity status of the ecosystem.

[0017] (2) In practical applications, considering the diversity of the natural environment, several representative experimental units are selected for monitoring, which can almost cover different habitat types in the ecosystem. In addition, within each experimental unit, several monitoring stations are randomly selected to conduct multi-type diversity surveys and calculations to improve the representativeness of the data and the reliability of statistical analysis.

[0018] (3) Instead of simply calculating the absolute value of the multi-type biodiversity index, the current value of the diversity index is compared with the historical value of the diversity index, and the comparison values ​​are assigned and added to obtain the final multi-type biodiversity index value. This can not only better reflect the dynamic changes of the ecosystem, but also avoid the impact of data contingency or outliers on the results, and improve the reliability and accuracy of the diversity index calculation.

[0019] (4) The assessment method of the present invention can select any appropriate biological group as the analysis object and be used in a variety of application scenarios, such as evaluating river health, evaluating ecological restoration projects, and formulating protection policies for global wetland ecosystems. It provides an overall measurement standard for biodiversity changes, effectively solves the assessment errors caused by different selections of diversity indicators, and provides a scientific basis for the horizontal management of global protection goals. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Attached Figure 1 This is a schematic diagram of biodiversity change indicators.

[0021] Attached Figure 2 This is a schematic diagram of the assessment process for biodiversity changes. DETAILED DESCRIPTION

[0022] A high-dimensional comprehensive method for evaluating the dynamic changes of ecosystem biodiversity. First, several experimental areas are randomly selected in the target ecosystem, and several parallel samples are randomly collected in each experimental area. The comprehensive biodiversity change index (CCBF) of the target group is analyzed and calculated from six key dimensions: species richness, functional richness, phylogenetic richness, species dissimilarity between communities, functional dissimilarity, and phylogenetic dissimilarity. The score is from 0 to 12 points. The higher the score, the greater the change in the biodiversity of the ecosystem.

[0023] Compare with Figure 1-2 , a high-dimensional comprehensive evaluation method for the dynamic changes of ecosystem biodiversity, characterized by: in view of the complex problems of indicator selection and quantification methods for measuring changes in ecosystem biodiversity, a high-dimensional comprehensive evaluation method for the dynamic changes of ecosystem biodiversity is developed. First, several experimental areas are randomly selected in the target ecosystem, and data from the area is monitored for two consecutive years, and a scientific and comprehensive indicator is used to judge the changes in biodiversity in the area. The blocks of different colors in the figure represent different types of biological samples.

[0024] Taking the biodiversity changes of benthic microorganisms in river ecosystems as an example, the specific implementation methods of the present invention are described in detail.

[0025] The method of the present invention comprises the following three steps in specific implementation: 1. Experimental Preparation (1) Select several experimental areas in the target ecosystem for two consecutive years, and then randomly collect several parallel samples in each experimental area for experiment.

[0026] (2) Establish five experimental areas 10-20 cm from the edge of the target river channel, with a certain distance between them (twice the width of the river channel). Use a sterilized sample spoon to collect sediment samples. The sample volume should be no less than 100 g and placed in a 10 ml centrifuge tube. Collect a total of 6 parallel samples from each experimental area and store them at -20 °C until they are transported back to the laboratory.

[0027] (3) Under laboratory conditions, genomic DNA was extracted according to the instructions of the DNA extraction kit corresponding to each type of sample, and the microbial species composition abundance data was obtained based on 16s and 18s high-throughput sequencing technology.

[0028] (4) In order to study the functional richness and functional diversity of related microbial communities, we measured and analyzed four genes related to carbon metabolism function: α-D-glucosidase (α-Glu), β-glucosidase (β-glu), glucokinase (GK) and cellobiohydrolase (CBH) to indicate the carbon metabolism capacity of microorganisms in the region.

[0029] 2. Calculate the data of the past two years in EXCEL, R language and MAGE software (1) Species richness and species diversity among communities were calculated using EXCEL software Taxonomic richness: the number of species in a community; (Formula 1) in, : Number of species observed; : OTUs with only one sequence; : OTUs with only two sequences.

[0030] Taxonomic dissimilarity between communities: differences in species composition between communities; (Formula 2) in, : The number of species in the intersection of community A and community B; : The number of species in the union of communities A and B.

[0031] The calculation results are shown in Table 1: Table 1 Results of species richness and species dissimilarity between communities in different years

[0032] (2) Functional richness and functional dissimilarity were calculated using R language Functional richness: the volume of functional space occupied by species (Formula 3) in, : The niche space occupied by species in community i; : Absolute value range of trait c Functional dissimilarity: the degree of overlap in functional space between communities (Formula 4) in, is the observed functional richness, is the expected functional richness, usually obtained by random sampling or model prediction, is the maximum functional richness possible in a given context.

[0033] The calculation results are shown in Table 2: Table 2 Results of functional richness and functional dissimilarity in different years

[0034] (3) Phylogenetic richness and phylogenetic dissimilarity were calculated using MAGE software and R language Based on the microbial gene sequences obtained by 16s and 18s high-throughput sequencing technology, a phylogenetic tree was drawn in MAGE software, and then the phylogenetic richness and phylogenetic dissimilarity were calculated in R language based on the abundance of species and the phylogenetic tree file. Phylogenetic abundance: the total length of the branches connecting all species on the phylogenetic tree (Formula 5) Where, Li: is the length of each branch on the phylogenetic tree; n: is the number of species included in the calculation.

[0035] Phylogenetic dissimilarity: the degree of overlap in phylogenetic tree branches between communities (Formula 6) Where n is the number of nodes or branches in the phylogenetic tree, is the length of the ith node or branch (usually representing evolutionary distance), is a weight, usually the number of samples under the node or branch.

[0036] The calculation results are shown in Table 3: Table 3 Results of phylogenetic richness and phylogenetic dissimilarity in different years

[0037] 3. Based on the historical values ​​and current values ​​of the six diversity indices, calculate the time change of each diversity index. The calculation formula is as follows: (Formula 7) in, is the current value of the diversity index, is the historical value of the diversity index.

[0038] The score is then calculated based on the value of δDI for each sample in all experimental areas: if δDI = 1, the score is 0; if δDI is higher than the median of all values ​​less than 1 and lower than the median of all values ​​greater than 1, the score is 1; if δDI is lower than the median of all values ​​less than 1 or higher than the median of all values ​​greater than 1, the score is 2.

[0039] The calculation results are shown in Table 4: Table 4 Calculation results of δDI of six indices in different years

[0040] 2) Then the scores of the six local indexes δDI are summarized to obtain the comprehensive change index of biodiversity (CCBF), calculated as follows: (Formula 8) The final calculation result was CCBF=9, which shows that the biodiversity in the area has changed significantly compared with before.

Claims

1. A high-dimensional comprehensive method for evaluating the dynamic changes of ecosystem biodiversity, characterized by The following steps are involved: (1) Randomly select several experimental areas in the target ecosystem and randomly collect several parallel samples in each experimental area; (2) Extract the historical biological community monitoring data of the area from the database of the local ecological monitoring station, and analyze and calculate the biodiversity and historical biodiversity of the target community from six dimensions: species richness, functional richness, phylogenetic richness, species dissimilarity among communities, functional dissimilarity, and phylogenetic dissimilarity; (3) Calculate the comprehensive biodiversity change index.

2. A method for high-dimensional comprehensive assessment of dynamic changes in ecosystem biodiversity according to claim 1, characterized in that In step (2), the species richness calculation formula is: （1） in, : Number of species observed; : OTUs with only one sequence; : OTUs with only two sequences.

3. The method for high-dimensional comprehensive assessment of dynamic changes in ecosystem biodiversity according to claim 1 is characterized by: In step (2), the function richness calculation formula is: (2) in, : The niche space occupied by species in community i; : The absolute value range of trait c.

4. The method for high-dimensional comprehensive assessment of dynamic changes in ecosystem biodiversity according to claim 1, characterized in that In step (2), the phylogenetic richness is the total length of the branches connecting all species on the phylogenetic tree; (3) Among them, L i : is the length of each branch on the phylogenetic tree; n: is the number of species included in the calculation.

5. The method for high-dimensional comprehensive assessment of dynamic changes in ecosystem biodiversity according to claim 1, characterized in that In step (2), the calculation formula for the species dissimilarity between the communities is: (4) in, : The number of species in the intersection of community A and community B; : The number of species in the union of communities A and B.

6. The method for high-dimensional comprehensive assessment of dynamic changes in ecosystem biodiversity according to claim 1, characterized in that In step (2), the functional dissimilarity calculation formula is: (5) in, : observed functional richness, : expected functional richness, obtained by random sampling or model prediction; : Maximum feature richness.

7. The method of high-dimensional comprehensive assessment of dynamic changes in ecosystem biodiversity according to claim 1, characterized in that In step (2), the phylogenetic dissimilarity calculation formula is: (6) Where n is the number of nodes or branches on the phylogenetic tree, : the length of the ith node or branch, : The number of samples under this node or branch.

8. The method of high-dimensional comprehensive assessment of dynamic changes in ecosystem biodiversity according to claim 1, characterized in that In step (3), calculating the comprehensive biodiversity change index includes the following steps: 1) Based on the historical and current values ​​of the six diversity indices, the temporal changes of each diversity index are calculated using the following formula: (7) in: is the current value of the diversity index, is the historical value of the diversity index; The score was calculated based on the δDI value of each sample in all experimental areas: if the δDI was 1, the score was 0; if the δDI was higher than the median of all values ​​less than 1 and lower than the median of all values ​​greater than 1, the score was 1; if the δDI was lower than the median of all values ​​less than 1 or higher than the median of all values ​​greater than 1, the score was 2; 2) Summarize the scores of the six local indexes δDI to obtain the comprehensive change index of biodiversity. The calculation formula is as follows: (8).

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