Method for monitoring forest soil health using functional groups of terrestrial arthropods

Abstract

This invention relates to an assessment method for monitoring forest soil health using functional groups of surface arthropods, comprising the following steps: S1 establishing assessment plots; S2 collecting surface arthropod samples, counting the number of individual surface arthropods, and calculating their proportions; S3 retrieving classification identification charts and functional group division tables based on family or order information; S4 determining the family or order information of surface arthropods based on the identification charts, compiling a family or order identification table using specimen photographs and ecological images, and classifying the data into six functional groups: predatory, herbivorous, detritivorous / omnivorous, beetle, predatory mite, and springtail, and counting the number of individuals in each of the six functional groups; S5 calculating the surface arthropod index at multiple trophic levels in natural and artificial Qinghai spruce forests; S6 determining the differences in the multitrophic level arthropod index between the assessment and control forests through statistical testing to assess changes in forest health. This invention can significantly reduce the time and cost of vegetation location observation and indoor soil measurement and analysis.

Description

Technical Field

[0001] This invention relates to the field of forest ecological environment technology, and in particular to an assessment method for monitoring forest soil health using functional groups of surface arthropods. Background Technology

[0002] Qinghai spruce forests are an important forest type in the arid northwest of China and a key component of the water conservation forests and ecological barriers of the Qilian and Helan Mountains. In terms of artificial forest construction, over the past decade, 105,300 hectares of forest closure and afforestation have been completed within the Gansu section of the Qilian Mountain National Park, along with 4,700 hectares of artificial afforestation. Afforestation methods mainly include landscape belt afforestation and water conservation afforestation: the former focuses on enhancing the landscape effect and embodying the aesthetic concept of forests, and is mostly distributed along important corridors such as main rivers, highways, and railways; the latter aims at water conservation and is mostly distributed in the low-altitude areas of the upstream mountainous regions of river basins. However, due to the lack of systematic guidance from ecohydrological theory, artificial forest construction generally suffers from problems such as whole-slope afforestation, contiguous distribution, and a single structural composition. Influenced by topographic factors such as slope aspect, slope position, slope gradient, and altitude, soil moisture exhibits significant spatial heterogeneity, leading to low survival rates and restricted growth in some areas of the slope after planting. At the same time, grazing activities and grazing bans have also had a profound impact on the soil physical and chemical properties, seedling regeneration and natural restoration process of Qinghai spruce natural forests, thereby threatening the long-term stability and ecosystem service functions of the forests.

[0003] A systematic assessment of the health of Qinghai spruce forests needs to consider the synergistic evolution of aboveground vegetation community structure, moss and litter layer characteristics, and underground soil physicochemical properties. However, there are significant differences in the response speed and sensitivity of aboveground and underground indicators to disturbances, and many exhibit a certain degree of lag, which poses considerable challenges to the dynamic monitoring and accurate diagnosis of forest stands. Currently, aboveground and underground monitoring of this forest stand still mainly relies on traditional quadrat surveys and laboratory analysis, which is not only time-consuming and labor-intensive but also difficult to meet the needs of large-scale, high-frequency assessments. Although remote sensing and UAV technologies can effectively infer the growth status of aboveground vegetation, their characterization of underground soil processes and biological communities is still limited by sensor deployment and stratified sampling analysis, resulting in insufficient spatiotemporal resolution and application efficiency. Soil organisms, as a key link connecting aboveground and underground ecological processes, can sensitively reflect changes in ecosystem function through their community dynamics. Among them, surface arthropods mainly inhabit the litter layer and soil surface layer, and are distributed in multiple trophic levels of the soil food web. They provide dual information on species diversity and functional diversity, and can quickly and accurately indicate the health status of the Qinghai spruce forest ecosystem, providing an ideal biological proxy indicator for building an efficient monitoring system.

[0004] The understory vegetation cover and diversity in both natural and planted Qinghai spruce forests are generally low, and the development of ground cover layers such as mosses is closely related to factors such as topography, disturbance intensity, and restoration years. Existing studies have shown that the arthropod community composition within Qinghai spruce forests exhibits close species exchange with adjacent grasslands and shrublands. At the species or genus level, arthropods exhibit strong regional specialization, with many groups distributed only in localized areas. However, screening for indicator groups at the family or order level is not only highly efficient and accurate in identification but also provides more stable and reliable indicators. Qinghai spruce forests harbor diverse arthropod groups originating from surrounding habitats, and their trophic structure is particularly complex in healthy conditions: broad-predatory groups such as centipedes, mirid spiders, spiders, and ground beetles belong to higher trophic levels and have a significant advantage in both quantity and richness; while the proportion of herbivorous groups such as leaf beetles and moth larvae is relatively low. Detritivorous and omnivorous groups such as tenebrionid beetles, ants, scarab beetles, mites, and springtails occupy lower trophic levels. They directly participate in litter decomposition and serve as important food sources for predatory predators, playing a crucial role in maintaining the length and complexity of the food web. Trophic functional groups and individual size are two core functional traits in arthropod functional diversity research, and their response patterns to changes in vegetation and soil environment can profoundly reveal the evolutionary patterns of soil food web structure and function.

[0005] In summary, forest soil health assessment requires monitoring multiple vegetation and soil biological indicators, as well as measuring a large number of soil physicochemical properties, but there is currently no suitable assessment method. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a simple and easy-to-implement assessment method for monitoring forest soil health using the functional groups of terrestrial arthropods.

[0007] To address the aforementioned problems, the present invention provides an assessment method for monitoring forest soil health using surface arthropod functional groups, comprising the following steps: S1 establishes an evaluation sample plot: In areas where it is necessary to assess natural and artificial Qinghai spruce forests, representative regions should be selected, and sample plots should be chosen within the Qinghai spruce forests. S2 established location monitoring plots for surface arthropods in natural and artificial Qinghai spruce forests, collected surface arthropod samples, counted the number of surface arthropod individuals, and calculated their proportions. S3 determined the composition of arthropod families or orders in the Qinghai spruce forest through plot surveys, and produced a classification identification guide and functional group division table for family or order information retrieval. S4 used the quadrat method to collect, evaluate, and compare surface arthropod samples from Qinghai spruce forests. Based on the retrieval atlas, the family or order information of the surface arthropods was determined. Using specimen photos and ecological images, a family or order key table was compiled, and information on six functional groups was divided into predatory, herbivorous, detritivorous / omnivorous, beetle, predatory mite, and springtail. The number of functional individuals of the six surface arthropods was counted. S5 calculates the multitrophic surface arthropod index of natural and artificial Qinghai spruce forests by counting the number of six arthropod functional groups; S6 uses statistical tests to determine the differences in arthropod indices between the assessment and control forest lands at multiple trophic levels, thereby assessing changes in forest land health.

[0008] In step S1, the distance between the sample plot and the edge of the forest land is >100m.

[0009] The terrestrial arthropods counted in step S2 refer to predatory, herbivorous, and saprophytic arthropods, as well as beetles, predatory mites, and springtails.

[0010] Compared with the prior art, the present invention has the following advantages: 1. This invention is based on the rapid and sensitive response of multitrophic level arthropod species and functional diversity to changes in vegetation and soil environment caused by grazing disturbance and artificial forest construction. It selects the most representative groups to construct a multitrophic level surface arthropod community index to reflect soil health and stability, thereby significantly reducing the cost of field surveys and indoor analysis, and improving work efficiency and the speed and accuracy of assessment.

[0011] 2. This invention comprehensively assesses the health changes of natural and artificial Qinghai spruce forest ecosystems under different grazing disturbance intensities from two dimensions: species diversity and functional diversity. It can effectively simplify the evaluation process, reduce monitoring costs, and significantly improve the reliability and operability of real-time dynamic assessment.

[0012] 3. This invention uses healthy Qinghai spruce forests as a control and determines the changes in soil health of Qinghai spruce forests by comparing and evaluating the differences in surface arthropod indices at multiple trophic levels between the forest land and the control forest land. Attached Figure Description

[0013] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0014] Figure 1 This is a schematic diagram illustrating the monitoring of arthropod samples, soil samples, and vegetation communities on the Earth's surface according to the present invention.

[0015] Figure 2 This is an NMDS ordination diagram of arthropod communities (a) and vegetation and soil factors (b) in natural Qinghai spruce forest (F1 without grazing, F2 with grazing) and artificial Qinghai spruce forest (F3) in the embodiments of the present invention.

[0016] Figure 3 This diagram illustrates the relationship between NMDS ordination axes 1 and 2 of the arthropod community and NMDS ordination axes 1 and 2 of the vegetation and soil environment in an embodiment of the present invention. Specifically: the top left diagram shows the relationship between NMDS ordination axis 1 of the arthropod community and NMDS ordination axis 1 of the vegetation and soil environment; the top right diagram shows the relationship between NMDS ordination axis 1 of the arthropod community and NMDS ordination axis 2 of the vegetation and soil environment; the bottom left diagram shows the relationship between NMDS ordination axis 2 of the arthropod community and NMDS ordination axis 1 of the vegetation and soil environment; and the bottom right diagram shows the relationship between NMDS ordination axis 2 of the arthropod community and NMDS ordination axis 2 of the vegetation and soil environment.

[0017] Figure 4 This invention illustrates the correlation between the number of six arthropod functional groups and vegetation-soil environmental variables in a Qinghai spruce forest. Wherein: CD - canopy closure; TD - tree density; TSD - tree seedling density; DBH - tree diameter at breast height (DBH); SS - shrub species; SC - shrub cover; SH - shrub height; HC - herb cover; HSN - number of herbaceous species; HH - herbaceous height; HB - herbaceous biomass; GCT - ground cover thickness; EC - soil electrical conductivity; SOC - organic carbon; TN - total nitrogen; C / N - carbon-nitrogen ratio; PS - predatory; HS - phytophagous; DS - saprophagous; PM - predatory mites; OM - beetle; ST - springtails; * P < 0.05, ** P < 0.01, *** P < 0.001.

[0018] Figure 5 This is a two-dimensional ordinal diagram showing the relationship between the quantity of six nutrient groups and vegetation and soil environmental variables in an embodiment of the present invention.

[0019] Figure 6 The Multitrophic Level Arthropod Index (MTI) of natural Qinghai spruce forest (F1 ungrazed, F2 grazed) and artificial Qinghai spruce forest (F3) in this embodiment of the invention. arthropods )Compare. Detailed Implementation

[0020] An assessment method for monitoring forest soil health using surface arthropod functional groups includes the following steps: S1 establishes an evaluation sample plot: When it is necessary to evaluate natural and artificial Qinghai spruce forests, select representative areas and choose sample plots within the Qinghai spruce forest. The distance between the sample plots and the forest edge should be >100m to reduce the impact of edge grasslands and shrublands.

[0021] S2 establishes locational monitoring plots for surface arthropods in natural and planted Qinghai spruce forests. The establishment of surface arthropod sampling plots must comprehensively consider differences in altitude, slope aspect, and micro-topography. Both natural and planted Qinghai spruce forests exhibit different management patterns, such as grazing or grazing bans; therefore, plot layout should reflect the impact of grazing disturbance, with separate monitoring plots established within grazing areas requiring independent study. Furthermore, Qinghai spruce forests are often distributed in patches or strips; to minimize disturbance to marginal habitats, monitoring plots should be located within the forest stand.

[0022] After establishing monitoring plots, it is advisable to collect surface arthropod samples during July and August, when plant diversity is at its highest. After collecting surface arthropod samples in natural and artificial Qinghai spruce forests, the samples are merged by quadrat, and the number of predatory, herbivorous, and saprophytic arthropods, as well as beetles, predatory mites, and springtails, is counted separately, and their proportions (the percentage of individuals in each group out of the total number of individuals) are calculated.

[0023] This invention can determine the close relationship between changes in surface arthropod communities and vegetation and soil environment by examining the influence of vegetation, soil environment and surface arthropod community composition, and can also determine whether the sampling time is feasible.

[0024] S3 determined the composition of arthropod families or orders in the Qinghai spruce forest through plot surveys, and produced a classification and identification guide and functional group division table for family or order information retrieval.

[0025] Baseline data on arthropods in Qinghai spruce forests are relatively scarce and show significant regional differences, necessitating systematic field surveys and specimen collection. Methods such as manual examination and trapping can be used to obtain surface arthropod specimens, simultaneously recording their behavioral information and photographing the specimens and their ecology. These findings will be used to compile a soil animal catalog, a family / order information retrieval guide, and a functional trait classification table.

[0026] Information on the families and orders of arthropods in natural and planted forests is primarily obtained through ecological surveys and fixed-point monitoring. Collected specimens and ecological photographs can be used to compile tables listing arthropod families or orders and their feeding patterns. Based on the obtained photographs of soil animal specimens and ecological images, a family / order identification guide and a trophic functional group classification table are compiled to enable rapid identification of arthropod trophic functional groups and population statistics.

[0027] When collecting surface arthropod samples using the trap method, a nested design was used for sample collection. Four sample collection sites were set up in each forest sampling area (each site was more than 50m apart). At each sample collection site, a 20m × 20m area was selected, and five 5m × 5m arthropod, soil, and vegetation survey areas were set up within each area. One trap collector was placed in each area. Figure 1Each location has one tree quadrat; each tree quadrat contains five shrub quadrats; each shrub quadrat contains one trap collector; and each shrub quadrat contains five herbaceous quadrats.

[0028] Surface arthropod samples were collected using an improved trap collector (patent number: ZL201621377547.4), and the preservation solution was 75% alcohol. The sample collection time was 10 days.

[0029] S4 used the quadrat method to collect, evaluate, and control surface arthropod samples from Qinghai spruce forests. Under magnifying glasses and stereomicroscopes, the family or order information of surface arthropods was determined according to the retrieval atlas. Using specimen photographs and ecological images, a family or order key table was compiled, and information on six functional groups was divided into predatory, herbivorous, detritivorous / omnivorous, beetle, predatory mite, and springtail. The number of functional individuals of the six surface arthropods was counted (average number of arthropods collected from each quadrat).

[0030] S5 calculates the multitrophic surface arthropod index of natural and artificial Qinghai spruce forests by counting the number of six arthropod functional groups.

[0031] Individual population data from six surface arthropod functional groups were used to calculate the proportion of each functional group (the percentage of its individuals out of the total number of individuals), and the average normalization was applied (X=(XX)). mean ) / (X max -X min )) Calculate the dimensionless value for each functional group, where: X is the ratio calculated for each functional group; X mean X is the average value; max X is the maximum value; min It is the minimum value.

[0032] These values ​​are summed and recorded as the Multi-trophic Index of Arthropods (MTI). arthropods ).

[0033] S6 uses statistical tests to determine the differences in arthropod indices between the assessment and control forest lands at multiple trophic levels, thereby assessing changes in forest land health.

[0034] Using the Kruskal-Wallis test (KW test) to measure the MTI of different natural and plantation Qinghai spruce forests arthropods The significance of the index differences was assessed by performing a log(x+1) transformation before data analysis. Using healthy Qinghai spruce forests as a reference, if the forest MTI (Mean Transmission Index) is monitored... arthropods There was a statistically significant difference between the index and healthy forest land. P <0.05 indicates that there is a risk to the monitoring of forest ecosystem health and stability, and that stability needs to be provided through human intervention and optimized management. Example

[0035] Natural Qinghai spruce forests are mainly distributed on the shady and semi-shady slopes of the central and eastern sections of the northern slope of the Qilian Mountains, at an altitude ranging from 2,500 to 3,300 meters. With the establishment of the Qilian Mountains National Park, some areas have implemented policies to relocate herders to reduce grazing disturbance, but some natural forest areas still experience varying degrees of degradation due to grazing. Planted Qinghai spruce forests are mostly distributed in lower-altitude hillside areas, with stands aged 30-40 years reaching maturity. According to preliminary surveys, the Sidaolong Protection Station and the Yangtai Resource Management Station, located in the core area of ​​the Qilian Mountains National Park, have implemented herder relocation and grazing bans, resulting in minimal disturbance to their natural Qinghai spruce forests due to grazing. However, in the adjacent Xishui Protection Station's Dayekou watershed, some Qinghai spruce forests are close to pastures and are still affected by grazing activities. Furthermore, the Dahuangshan Protection Station has a large area of ​​mature planted Qinghai spruce forests, with planting ages ranging from 30 to 40 years.

[0036] This invention selects three typical sample plots in the aforementioned area: within the Yangtai Resource Management Station of the Sidaolong Protection Station, a natural Qinghai spruce forest at an altitude of approximately 2900 meters is selected as an undisturbed natural forest sample plot (F1: 38°26′02.07″N, 99°55′27.63″E); within the Pailugou watershed of the Xishui Protection Station, a natural Qinghai spruce forest at an altitude of approximately 2900 meters that is affected by grazing is selected as a grazing-disturbed natural forest sample plot (F2: 38°31′43.00″N, 100°16′10.49″E); and within the Dahuangshan Protection Station, a mature Qinghai spruce plantation at an altitude of approximately 2900 meters is selected as a plantation sample plot (F3: 38°25′49.83″N, 101°15′10.85″E).

[0037] Surveys conducted in the eastern, central, and western sections of Qilian Mountain National Park revealed a total of 316 species of arthropods belonging to 3 phyla, 7 classes, 23 orders, and 125 families. At the family level, herbivorous, predatory, and detritivorous arthropods accounted for a relatively high proportion, at 35.5%, 22.6%, and 20.2%, respectively. At the species level, predatory, herbivorous, and detritivorous groups accounted for 40.3%, 32.0%, and 12.9%, respectively. In the mountain grassland area, the activity density and taxonomic richness of large soil arthropods were higher than in arbor forests, shrub forests, and subalpine shrub grasslands, with community evenness initially increasing and then decreasing with increasing altitude. Conversely, the activity density and taxonomic richness of medium-sized soil arthropods were lowest in the mountain grassland area, exhibiting the opposite trend to that of large groups. The arthropod diversity in Qinghai spruce forests, grasslands, and shrub forests is highly sensitive to factors such as altitude gradient, grazing disturbance, and temperature increases, and can further influence the structure and function of the soil food web through changes in trophic and non-trophic relationships.

[0038] 1. Obtain baseline information on the composition of terrestrial arthropod families or orders, functional groups, and vegetation and soil environment. From July to August 2021, arthropod samples were collected from natural and planted Qinghai spruce forests using the trap method. First, monitoring plots were established within the natural and planted Qinghai spruce forests. Four relatively independent locations were selected within each forest plot to set up arthropod sampling areas. Each area was divided into 20m × 20m quadrats, and five 5m × 5m traps were set up diagonally within each quadrat to collect arthropod samples and mixed soil samples. The traps were made of plastic cups (7.5cm in diameter and 10cm in height), and 75% alcohol solution was used for preservation. The sample collection period was 10 days. The collected arthropod samples were preserved in 75% alcohol solution and brought back to the laboratory for identification, classification of families or orders, and population counts. A table of arthropod nutritional functional groups was then established, as shown in Table 1.

[0039] Table 1. Classification of Nutritional Functional Groups in Arthropods After collecting surface arthropod samples, the community structure of trees, shrubs, and herbs, as well as the thickness of the ground cover layer, were investigated. Mixed soil samples were collected, brought back indoors, air-dried, and then the soil pH, electrical conductivity, organic carbon, and total nitrogen content were measured. The C / N ratio (the ratio of organic carbon to total nitrogen content) was calculated.

[0040] 2. Determine the changing relationships between surface arthropods, vegetation, and soil environment in natural and artificial Qinghai spruce forests. The arthropod community composition of natural and artificial Qinghai spruce forests differs significantly. The arthropod community composition differs considerably between undisturbed natural Qinghai spruce forests and both undisturbed and artificial Qinghai spruce forests. Furthermore, significant differences also exist between undisturbed natural and artificial Qinghai spruce forests. Figure 2 ).

[0041] The average dissimilarity of arthropod community composition between undisturbed natural Qinghai spruce forests and disturbed natural and planted Qinghai spruce forests was 58.5% and 72.6%, respectively, while the average dissimilarity between disturbed natural and planted Qinghai spruce forests was 44.2%. Significant differences also existed in vegetation and soil environmental factors between natural and planted Qinghai spruce forests, with the difference between natural and planted Qinghai spruce forests being greater than the difference between the two natural forest areas. Figure 2 The NMDS ordination axis 1 of arthropod community composition showed a significant quadratic curve relationship with both ordination axes 1 and 2 of vegetation and soil environmental changes. Ordination axes 1 and 2 of vegetation and soil environmental changes explained 78% and 50% of the changes in NMDS ordination axis 1 of arthropod community composition, respectively. Figure 3The NMDS ordination axis 2 of arthropod community composition showed a linear relationship with both ordination axes 1 and 2 of vegetation and soil environmental changes. Ordination axes 1 and 2 of vegetation and soil environmental changes explained 25% and 34% of the changes in NMDS ordination axis 2 of arthropod community composition, respectively. Figure 3 This shows that there is a close relationship between changes in surface arthropod communities, vegetation, and soil environment in natural and artificial Qinghai spruce forests, and changes in surface arthropod communities can reflect changes in vegetation and soil environment.

[0042] 3. Analyze the relationship between arthropod trophic functional groups and vegetation and soil environmental factors. Correlation analysis was used to determine the correlations between 17 vegetation and soil factors, including trees, shrubs, herbs, ground cover, and soil physicochemical factors, and the number of six arthropod functional groups. Figure 4 Predatory arthropods showed a significant negative correlation with shrub species and total soil nitrogen. P <0.05, showing a significant positive correlation with soil electrical conductivity ( P <0.05, and showed a highly significant negative correlation with tree seedling density, shrub cover, ground cover thickness, soil organic carbon, and carbon-nitrogen ratio. P <0.01); saprophytic arthropods were significantly positively correlated with shrub cover, ground cover thickness, soil organic carbon, total nitrogen, and carbon-nitrogen ratio. P <0.05); Predatory mites were significantly positively correlated with tree seedling density, shrub height, and total soil nitrogen. P <0.05, and showed a highly significant positive correlation with shrub species, shrub cover, herbaceous biomass, ground cover thickness, soil organic carbon, and carbon-nitrogen ratio. P <0.01, showing a highly significant negative correlation with soil electrical conductivity ( P <0.01); Springtails showed a significant positive correlation with shrub species, herbaceous biomass, and ground cover thickness ( P <0.05, and showed a significant negative correlation with tree density, soil pH, and electrical conductivity. P <0.05, and showed a highly significant positive correlation with tree diameter at breast height, shrub canopy, soil organic carbon, and carbon-nitrogen ratio. P <0.01, showing a highly significant negative correlation with canopy closure ( P <0.01).

[0043] The RDA ordination results of six arthropod functional groups in natural and artificial Qinghai spruce forests with and without grazing disturbance, in relation to vegetation and soil environmental variables, showed that ( Figure 5 Five factors explained 84.4% of the variation in trophic structure in arthropod communities (Ordination axis 1: F = 11.42, P = 0.004; All sort axes:F = 6.46, P = 0.002), the ranking results reflect the relationship between arthropod trophic structure and changes in vegetation and soil environment well. The variable decomposition results are shown in Table 2.

[0044] Table 2. RDA analysis determined the relative contributions of vegetation and soil environmental factors to the population changes of six arthropod functional groups in undisturbed, grazing-disturbed, and planted Qinghai spruce forests. Note: SC - Shrub cover; SH - Shrub height; SOC - Organic carbon; HSN - Number of herbaceous species.

[0045] The table shows that shrub cover, shrub height, and soil organic carbon are the main factors affecting changes in the trophic structure of arthropods. F = 16.1, P = 0.002; F = 3.3, P = 0.022; F = 2.7, P = 0.020), which explained 61.7%, 10.4%, and 7.1% of the variation, respectively; followed by the number of herbaceous species, which also has some explanatory power for the distribution of terrestrial arthropods. From the ranking Figure 5 It is evident that there are significant changes in the trophic structure of the arthropod communities in the three types of Qinghai spruce forests. The arthropod communities in undisturbed natural Qinghai spruce forests are significantly different from those in undisturbed natural Qinghai spruce forests and plantations. There are also certain differences in the arthropod communities in undisturbed natural Qinghai spruce forests and plantations.

[0046] 4. Using arthropod multitrophic indices to indicate changes in the health of Qinghai spruce forests. Six terrestrial arthropod trophic functional groups encompass high, medium, and low trophic levels, and also include large and medium-sized arthropod groups in terms of body size. The relative abundance of these six groups was calculated using individual numbers to reflect changes in trophic structure. Relative abundance data for the six functional groups in natural (ungrazed and grazed) and planted Qinghai spruce forests were normalized using mean (X=(XX)). mean ) / (X max -X min The dimensionless processing is performed. Where: X is the ratio calculated for each functional group; X... mean X is the average value; max X is the maximum value; min It is the minimum value.

[0047] Subsequently, the dimensionless values ​​of the six functional groups were summed to calculate the Multitrophic Level Arthropod Index (MTI). arthropodsThe Kruskal-Wallis test (KW test) was used to test the MTI of different forest lands. arthropods The significance of the index differences was assessed by performing a log(x+1) transformation before data analysis. This included comparisons of natural (ungrazed and grazed) and artificial Qinghai spruce forest MTI. arthropods Significant differences exist in the indices, with grazing disturbance affecting natural Qinghai spruce forests (MTI). arthropods The index was significantly lower than that of natural Qinghai spruce forests without grazing disturbance, while the MTI of artificial Qinghai spruce forests was significantly lower. arthropods The index was significantly lower than that of natural Qinghai spruce forests disturbed by grazing ( Figure 6 Therefore, the multitrophic level arthropod index calculated using six arthropod functional groups not only indicates changes in the health of natural and planted Qinghai spruce forests, but it can also assess the impact of grazing disturbance on forest health in natural Qinghai spruce forests.

Claims

1. An assessment method for monitoring forest soil health using surface arthropod functional groups, comprising the following steps: S1 establishes an evaluation sample plot: In areas where it is necessary to assess natural and artificial Qinghai spruce forests, representative regions should be selected, and sample plots should be chosen within the Qinghai spruce forests. S2 established location monitoring plots for surface arthropods in natural and artificial Qinghai spruce forests, collected surface arthropod samples, counted the number of surface arthropod individuals, and calculated their proportions. S3 determined the composition of arthropod families or orders in the Qinghai spruce forest through plot surveys, and produced a classification identification guide and functional group division table for family or order information retrieval. S4 used the quadrat method to collect, evaluate, and compare surface arthropod samples from Qinghai spruce forests. Based on the retrieval atlas, the family or order information of the surface arthropods was determined. Using specimen photos and ecological images, a family or order key table was compiled, and information on six functional groups was divided into predatory, herbivorous, detritivorous / omnivorous, beetle, predatory mite, and springtail. The number of functional individuals of the six surface arthropods was counted. S5 calculates the multitrophic surface arthropod index of natural and artificial Qinghai spruce forests by counting the number of six arthropod functional groups; S6 uses statistical tests to determine the differences in arthropod indices between the assessment and control forest lands at multiple trophic levels, thereby assessing changes in forest land health.

2. The assessment method for monitoring forest soil health using surface arthropod functional groups as described in claim 1, characterized in that: In step S1, the distance between the sample plot and the edge of the forest land is >100m.

3. The assessment method for monitoring forest soil health using surface arthropod functional groups as described in claim 1, characterized in that: The terrestrial arthropods counted in step S2 refer to predatory, herbivorous, and saprophytic arthropods, as well as beetles, predatory mites, and springtails.

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