Artificial construction method of ecosystems

Abstract

To enable both ecological conservation and economic efficiency by reducing the risk of requiring replantation after planting tall trees in artificial green spaces, and creating foundations for building ecosystems that respond to changes in needs in the next 20 to 30 years while offering ecosystems to the use that meets the current social needs such as solar power generation.SOLUTION: The method comprises: identifying support organisms that are compatible with tall trees in an artificial tall tree forest for the tall trees that make up a tall tree forest in the artificial green space; and introducing the support organisms into the artificial green space at the same time as or before introducing the tall trees into the artificial forest. In addition, ecosystems with low ecosystem service evaluation are modified to build ecosystems that can create fertile soil while performing solar power generation, etc.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for artificially constructing an ecosystem. [Background technology]

[0002] Traditionally, ecosystems have been used and altered artificially, but sometimes ecosystems are left in a state where they are unable to fully function, or are used or altered in such a way that their functions are impaired. For example, abandoned farmland and degraded forests (abandoned forests) are examples of ecosystems that, through moderate use by humans, have been unable to fully utilize their productive functions, which had been richly productive. Another example of the latter is farmland ecosystems where excessive cultivation has caused soil degradation and reduced productivity. Disturbed areas where vegetation has been lost and bare due to construction work for houses, condominiums, buildings, roads, and other structures, or landslides, can also be said to be areas where ecosystem functions have been impaired.

[0003] In the past, artificial ecosystems have been constructed on land that is no longer functioning as an ecosystem. For example, artificial green spaces have been constructed by artificially restoring vegetation to bare land that has lost vegetation due to urban development. In particular, in urban areas, a lot of construction work has been carried out and various artificial green spaces have been constructed, but natural ecosystems like those in mountains and fields are scarce.

[0004] Artificial green spaces in urban areas have traditionally been designed to have an urban aesthetic, and constructed so that the designed artificial green space is complete at the same time as construction is completed. In recent years, there has been a demand for such artificial green spaces in urban areas to have scenery and functions (e.g., biodiversity conservation functions) that are close to those of natural ecosystems. In order to build artificial green spaces with scenery and functions that are close to those of natural ecosystems, it is preferable to plant multiple trees that grow to a certain height, and traditionally, when constructing an artificial green space, trees that have grown to a height of several meters are planted and construction of the artificial green space is completed.

[0005] In urban artificial green spaces constructed in this way, natural regeneration of trees is usually difficult, so if trees die or are damaged after construction, new trees must be planted. However, it has been pointed out that planting trees several meters tall after completing construction of artificial green spaces in urban areas is costly (Patent Document 1).

[0006] In response to the above-mentioned problems, Patent Document 1 proposes a construction method for artificial green spaces in urban areas, in which multiple vegetation, including climax forests, is constructed in the artificial green spaces, thereby improving the natural recovery of the vegetation in the artificial green spaces after construction.

[0007] In recent years, there have been concerns that power development projects for renewable energy sources (typically solar power), for which demand is growing in order to realize a carbon-free society, may involve development that could damage the functions of the natural ecosystems that existed in the areas where the power is developed. For this reason, when developing a power source, surveys are conducted on the ecosystems of the proposed development site and its surrounding areas, and measures are taken to preserve them.

[0008] Furthermore, earthquakes, heavy rain damage (floods, landslides, etc.), forest fires, and other natural disasters have been increasing recently, calling for the artificial construction of ecosystems in the reconstruction of disaster-stricken areas. Examples of the artificial construction of ecosystems in the reconstruction of disaster-stricken areas include the restoration of agricultural and forestry land and the greening of the slopes of restored roads. In the artificial construction of ecosystems in disaster reconstruction, there are cases where the restoration of ecosystems is attempted to the same as before the disaster so that agriculture, forestry, and lifestyles can be carried out in the same places as before the disaster, but since disasters also cause population movement (migration), ecosystems such as agricultural and forestry land that were reconstructed at great cost may not be used to the extent that it is commensurate with the cost invested. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent Publication No. 2018-42527 Summary of the Invention [Problem to be solved by the invention]

[0010] In the method described in Patent Document 1, a community ring consisting of climax forests and plant communities in the transitional stages leading to the climax forest is arranged in multiple green spaces scattered over a wide area. In order to arrange artificial green spaces that form community rings leading to the climax forest in multiple plots of land like this, it is necessary to obtain consent from each owner or manager of the multiple plots of land, which requires time and cost.

[0011] In addition, if there is an ecosystem with high ecological value in the area where power generation is to be developed, even if environmental conservation efforts are made during the power generation development, some degree of decline in the value and function of the ecosystem is unavoidable. Note that a high ecosystem value means that the ecosystem has a high evaluation value for ecosystem services, that is, the ecosystem has many or large beneficial functions, for example, it conserves a diverse range of organisms, is a habitat for valuable plants and animals, has a high carbon dioxide absorption capacity, is highly productive for agricultural and forestry products, and has high soil erosion prevention and water retention capabilities.

[0012] In this way, when the value of an ecosystem is high before it is used or altered by humans, it takes a lot of effort to prevent its value from decreasing due to artificial use or alteration. For this reason, investing in ecosystem conservation increases development costs, while not investing in it leads to a decrease in the value of the ecosystem, making it difficult to balance economic efficiency with environmental conservation.

[0013] Alternatively, when constructing ecosystems artificially as part of disaster recovery, particularly when restoring agricultural and forestry land, it is thought that the recovery of disaster-stricken areas can be facilitated if the ecosystem is constructed artificially with as little manpower (cost) as possible, taking into account population movement after the disaster, and if the restored agricultural and forestry land can be used and managed with less manpower (cost) than before the disaster.

[0014] The present invention provides a method for forming an artificial green space that can reduce the cost of replacing damaged trees after construction and can construct an artificial green space with trees that reach a height of 3 to 5 m or more even on a single plot of land with a small construction area. The present invention also provides a method for artificially constructing an ecosystem that can enjoy the benefits of aging.

[0015] The present invention further provides a method for avoiding the decline in the value of an ecosystem when it is artificially utilized or altered. In particular, the present invention provides a method for artificially constructing an ecosystem, which takes the opportunity of altering an ecosystem whose function (value) has declined due to its artificial utilization to alter it, thereby constructing an ecosystem of higher value while increasing the productivity and utility value of the land on which the ecosystem exists.

[0016] The present invention also provides a method for artificially constructing an ecosystem that can reduce the restoration costs of land (disturbed land) that has been affected by a natural disaster or the like and lost its vegetation. [Means for solving the problem]

[0017] In a first aspect of the present invention, for a tall tree that is to form a tall tree forest in an artificial green space, a supporting organism that is compatible with the tall tree in the artificial forest is identified, and the supporting organism is introduced into the artificial green space at the same time as the tall tree is introduced into the artificial forest or prior to the introduction of the tall tree.

[0018] In this specification, "tall tree forest" refers to a forest in which the dominant species in a natural ecosystem are tall trees that reach a height of 10 m or more, particularly 20 m or more. In this specification, tall trees that can form a tall tree forest and are selected as tall trees that constitute the highest position (highest layer) of a terrestrial ecosystem to be constructed in an artificial green space are referred to as "tall trees." In artificial green spaces, tall trees are often pruned to a height of about 5 to 10 m, so the height of tall tree forests in artificial green spaces may be artificially limited to about 10 m.

[0019] In this specification, a stable plant community in which tall trees determined to be tall trees to be introduced into an artificial green space form the highest layer is referred to as a "climax forest." A "stable plant community" refers to a plant community that can be maintained without artificial planting of plants.

[0020] In this specification, organisms that are compatible with tall trees (sometimes referred to as "support organisms") refer to organisms, particularly plants or microorganisms, or both, that are in a relationship that forms a symbiotic relationship beneficial to the growth of tall trees determined to be tall trees. A "symbiotic relationship beneficial to the growth of tall trees" refers to a relationship that promotes the growth and survival of tall trees, or enhances their resistance to stresses such as dryness, high temperatures, low temperatures, wind and snow, and other weather stresses and pest and disease stresses.

[0021] More specifically, these include low- and mid-storey plants and herbaceous plants that increase the weather stress resistance of tall trees by covering the bases of the trees, plants and microorganisms that produce repellents against insects that cause feeding damage to tall trees and thereby reduce pest stress in tall trees, and soil microorganisms that live symbiotically with the roots of tall trees to help the trees absorb nutrients and water.

[0022] When introducing herbaceous plants as supporting organisms into an artificial green space, a herbaceous plant community with herbaceous plants as the dominant species may be constructed before introducing tall trees into the artificial green space. In this way, an artificially designed vegetation succession can be generated on the same piece of land, and the plant community can be intentionally changed over the course of years from the start of construction of the artificial green space, thereby inducing an artificially designed change in the landscape over time.

[0023] In another aspect of the present invention, a different type of ecosystem (future ecosystem) that can be constructed on land that contains an ecosystem in a state where the functions that the ecosystem can perform are not being fully utilized (the evaluation value of ecosystem services is low) is constructed. Specifically, the value of the ecosystem that exists on the land before modification (existing ecosystem) is calculated, and the value (future value) that can be obtained from the land by constructing a different type of ecosystem (future ecosystem) from the current ecosystem that can be constructed while using the land artificially is calculated. Then, the land is modified in order to use the land to construct a future ecosystem whose future value will be higher than the value of the current ecosystem continuing to exist.

[0024] Ecosystem types can be broadly categorized into forest ecosystems dominated by trees, herbaceous ecosystems dominated by herbaceous plants, and artificial ecosystems such as farmland and parks where artificial plantings are performed and vegetation is managed by hand. Forest ecosystems and herbaceous ecosystems can be further classified according to the state of manual management or use (e.g. "abandoned," "semi-abandoned," "managed"), and according to the vegetation (e.g. "artificial forest," "bamboo forest," "evergreen tall tree forest," "mixed coniferous-broadleaf forest," etc.).

[0025] The future ecosystem may be transitioned over a predetermined period of time after the existing ecosystem of the proposed modification site is altered. In other words, the future ecosystem may include two or more ecosystems of different types. For example, in order to artificially transition from one type of ecosystem (first future ecosystem) to another type of ecosystem (second future ecosystem), plants that have been artificially symbiotically formed with microorganisms that have been isolated and cultured from the soil of the proposed modification site and that contribute to the growth of plants that are desired to be dominant in the second future ecosystem may be introduced into the proposed modification site.

[0026] In this way, by introducing microorganisms that are beneficial to the construction of the future ecosystem to the proposed site, it is expected that the construction of the future ecosystem will be promoted as well as soil biological properties, especially the diversity of the microflora. Also, by introducing carbon sources such as plant residues and charcoal to the proposed site, the carbon sources will become habitats and energy sources for microorganisms, which will promote the improvement of soil biological properties (increasing biomass and / or increasing biota diversity).

[0027] In the present invention, these various types of ecosystems are valued. The value of an ecosystem can be evaluated, for example, by a known evaluation method related to the economic evaluation of ecosystem services. The economic evaluation of ecosystem services may be performed by evaluating only a part of the ecosystem functions linked to the ecosystem services. When evaluating the value of a part of the ecosystem functions, at least one of the supply service of the ecosystem, which is the supply function of materials such as wood and food, or the regulating service, which is the function related to the absorption and fixation of carbon dioxide, is evaluated, and preferably both. Both functions are easy to quantify as economic value. It is also preferable to evaluate at least one of the regulating services, which are the control of water circulation and the protection function against natural disasters, and the infrastructure service, which is the soil formation function.

[0028] The supply function may be quantified as the productivity (land productivity) when a certain commodity is produced, and the carbon dioxide absorption and fixation function may be quantified as the amount of carbon dioxide absorbed and fixed or the carbon dioxide emission source trading price based on that.

[0029] It is preferable to assess the value of the current and future ecosystems by assessing the same functions, but different functions may be assessed as long as a reasonable comparison can be made between the value of the current and future ecosystems for a specified period after modification. For example, the value of the current and future ecosystems may be compared based on their most valuable functions (e.g., the water cycle control function for the current ecosystem and the carbon dioxide absorption and fixation function for the future ecosystem). Alternatively, two or more different highly valuable functions of each ecosystem may be assessed.

[0030] The value of the current ecosystem and future ecosystem should be calculated for at least 20 years after modification, preferably 25 years or more, and more preferably 30 years or more. Since ecosystems that have been artificially modified are prone to change for about 20 years, it is easier to build the future ecosystem intended at the time of modification by determining the management and use form of the modified ecosystem for about 20 to 30 years after modification. In addition, after about 30 years have passed since modification, differences from the economic society at the time of modification become apparent. For this reason, if the specified period is set to 20 to 30 years, it is easier to consider whether or not to maintain the ecosystem constructed after modification at the time the specified period has passed, and to build an ecosystem that is in line with the times.

[0031] Another aspect of the present invention is preferably used in disturbed areas where soil has been exposed (i.e., denuded) due to the accumulation of sediment or the loss of previous vegetation caused by natural disasters, etc., and realizes low-cost reconstruction of disaster areas (ecosystem recovery) by artificially utilizing the ecosystem-building and stabilizing powers of natural ecosystems. Specifically, prior to the introduction of woody plants (planted trees) to be planted in the target area (disturbed area) where an ecosystem is to be artificially constructed, a precursor plant (lead plant) that is beneficial for the growth of the plant is introduced. The lead plant and the planted tree may be of the same species, and examples of the plant that can be used include green manure plants that live symbiotically with nitrogen-fixing bacteria, mycorrhizal symbiotic trees that live symbiotically with mycorrhizal fungi, and artificial symbiotic trees in which non-mycorrhizal filamentous fungi are artificially symbiotically formed.

[0032] In cases where the surface soil of disturbed land has been washed away or where the topography has changed due to the accumulation of sediment, etc., and where drainage may have changed since before the disaster, it is preferable to use herbaceous green manure plants as lead plants. Herbaceous green manure plants grow quickly and can cover the surface of the disturbed land to prevent soil erosion, and their growth can also be used to determine the quality of drainage of the disturbed land.

[0033] Furthermore, if the disturbed land is on a slope that tends to dry out, it is preferable to plant pioneer species such as alpines and pines that can grow in nutrient-poor soil by coexisting with mycorrhizal fungi. However, special cultivation management techniques and materials are required to artificially induce mycorrhizal fungi to coexist with trees. For this reason, when artificially constructing an ecosystem over a wide area, it is not easy from the standpoints of technology and cost to plant trees that have artificially caused mycorrhizal fungi to coexist with them.

[0034] Therefore, in the present invention, natural soil blocks cut from a natural ecosystem in the disturbed area or its neighboring areas (within 30 km, preferably within 10 km from the disturbed area, the same applies hereinafter in the present specification) or artificial plant blocks in which mycorrhizal fungi have been artificially symbiotically grown on lead plants are scattered in the disturbed area. The blocks are preferably about 10 cm to 40 cm thick, preferably about 15 cm to 30 cm thick, and have a side length of 15 to 50 cm, preferably about 20 to 30 cm (surface area of ​​200 to 2,500 cm2, preferably 300 to 500 cm2). The blocks are preferably arranged at intervals of 3 to 200 m, particularly about 5 to 10 m.

[0035] In this specification, the term "mediator microorganism" refers to a microorganism that can support the growth of lead plants and planted trees that are introduced into disturbed areas prior to planting trees. As the mediator microorganism, it is advisable to select a microorganism that has a friendly function (i.e., promotes growth, has disease control effects, etc.) with both the plant selected as the planted tree and the lead plant from among the soil microorganisms present in the disturbed area or its neighboring areas, by using the microbial analysis method by Toju described later, literature surveys, microbial experiments such as inoculation tests, etc. In particular, non-mycorrhizal filamentous fungi contained in the soil of the disturbed area or its neighboring areas are preferable as the mediator microorganism. Among non-mycorrhizal filamentous fungi, filamentous fungi called endophytic fungi penetrate mycelium, sclerotium, etc. into the plant body and live symbiotically with the plant, but do not form mycorrhizae. In addition to endophytic fungi, non-mycorrhizal filamentous fungi also include saprophytic fungi and soil fungi, which can be artificially cultured and grown in a general microbial culture medium (such as oatmeal medium) without symbiotically living with the plant. Therefore, by selecting non-mycorrhizal fungi contained in the soil of disturbed areas and nearby areas that coexist with lead plants and are beneficial to the growth of planted trees, isolating and cultivating these fungi, and introducing the cultures into disturbed areas so that they artificially coexist with lead plants and planted trees, it will be possible to artificially construct an ecosystem more easily and technically in terms of cost.

[0036] In this invention, the power of the natural ecosystem (specifically, indigenous microorganisms) is utilized when artificially constructing an ecosystem in disturbed land. Therefore, when the regenerated ecosystem is used for agriculture and forestry, the soil microbial flora of the regenerated site can be utilized to draw out the ecosystem's ability to control pests and diseases and its stability, making it easier to carry out low-impact agriculture and forestry. Effect of the Invention

[0037] According to the present invention, by artificially generating vegetation succession that mimics the vegetation succession that would occur if the artificial green space were placed in a natural state, it is possible to form an artificial green space that can reduce the effort and cost of replanting damaged trees. Furthermore, according to the present invention, it is possible to easily form an artificial green space that has a landscape and functions close to a natural ecosystem. Furthermore, according to the present invention, it is possible to form an artificial green space that allows you to enjoy the changes that occur over time.

[0038] Furthermore, according to the present invention, for example, abandoned forests that are not properly managed, do not serve as carbon dioxide sinks, and have exposed soil, resulting in reduced soil retention and rainwater retention functions, can be converted into solar power generation sites, and a separate ecosystem (constructed ecosystem) can be constructed while generating solar power, thereby enhancing biodiversity conservation functions and soil retention functions.

[0039] Furthermore, according to the present invention, the difficulty of the techniques and the effort (cost) required to artificially construct ecosystems in disturbed areas such as disaster-stricken areas can be reduced, making it possible to regenerate disaster-stricken areas into areas where low-impact agriculture and forestry can be carried out. [Brief description of the drawings]

[0040] [Figure 1] Examples of data obtained from environmental DNA analysis of soil microbiomes [Diagram 2] An example of analysis of the symbiotic relationship between soil microbiota and plants (Toju, H. et al. Assembly of complex plant-fungus networks. Nature Communications 5:5273 DOI:10.1038 / ncommms6273(2014)) [Diagram 3] A table showing plants that constitute a climax forest that can naturally be formed in an artificial green space according to the first embodiment of the present invention. [Figure 4] Schematic diagram showing the proposed site for modification according to the third embodiment of the present invention. [Diagram 5] Larch seedlings as planted trees used in the fourth embodiment of the present invention (seedlings that have not been artificially symbiotically grown with non-mycorrhizal fungi; two pots on the left and seedlings that have been symbiotically grown with non-mycorrhizal fungi; two pots on the right) DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] As a first embodiment of the present invention, an example will be described below in which a plot of land measuring 110 m x 50 m is assumed to be a proposed site for constructing an apartment building, and an artificial green space measuring 110 m x 5 m is to be formed thereon.

[0042] The proposed site for the artificial green space (hereinafter referred to as the proposed site) is a disturbed area in the inland area of ​​the Kinki region where the vegetation that existed before construction was lost due to construction work for residential land development. The area in which the proposed site is located is an area where the potential natural vegetation is said to be a climax forest of diapa-glaucian communities. In terms of climate, this area can form a climax forest with the tree layer consisting of Quercus myrsinais, Castanopsis cuspidata, Castanopsis stenophylla, and Quercus serrata in addition to the diapa-glaucian communities with Quercus glauca forming the tree layer.

[0043] Therefore, for the planned site, as the dominant species of the tall tree layer of a forest stand similar to a climax forest that can be artificially constructed (hereinafter, "climax forest"), candidates for tall trees are Quercus glauca, Quercus myrsinae, Quercus serrata, Quercus stenophylla, and Quercus akasakii, and one or more species are selected from among them as tall trees. In this embodiment, when selecting tall trees, the soil microflora of the planned site is referred to, and tree species that are compatible with the soil microflora of the planned site, that is, that can build a good symbiotic relationship with the soil microflora of the planned site, are selected.

[0044] Specifically, soil samples will be collected from the planned site, as well as soil and plant roots from a mountain forest located approximately 1 km from the planned site as a natural ecosystem in the vicinity of the planned site. The collected soil and plant roots will be subjected to environmental DNA analysis. Environmental DNA analysis can be performed using standard methods, and any commonly available environmental DNA analysis service can be used.

[0045] Using data obtained from environmental DNA analysis, the soil microbiome of the proposed site and the soil microbiome of the natural ecosystem near the proposed site will be analyzed, and the symbiotic relationship between the soil microorganisms that make up the soil microbiome and the candidate tall tree species will be analyzed. Methods for analyzing the symbiotic relationship between tall trees and soil microorganisms include literature research, collation with microbial databases, and the analysis method described in Toju, H. et al. Core microbiomes for sustainable agroecosystems. Nature Plants 4 247-257 (2018) (hereinafter referred to as "Toju's microbial biome analysis").

[0046] By analyzing the soil microflora of the proposed site in this way, it is possible to understand what kind of soil microorganisms exist on the proposed site. Furthermore, by analyzing the soil microflora of the natural ecosystem near the proposed site, it is possible to understand the symbiotic relationship between the plants and soil microorganisms that make up the natural ecosystem near the proposed site. In particular, when the natural ecosystem near the proposed site includes a candidate for a tall tree, by analyzing the symbiotic relationship between the organisms that make up the natural ecosystem, it is possible to identify soil microorganisms that have formed a favorable symbiotic relationship with the candidate tall tree in that natural ecosystem, and soil microorganisms that are beneficial for the introduction of tall trees to the proposed site.

[0047] Figure 1 shows an example of the results of a soil microbiome analysis using environmental DNA analysis. Figure 2 shows an example of an analysis of the symbiotic relationship between plants and microbes using microbiome analysis. Note that the microbes analyzed in Figures 1 and 2 were filamentous fungi and did not include bacteria. Figure 1 shows the ratio of the abundance of DNA derived from multiple microbial species groups contained in each sample for 16 samples. Figure 2 also shows the symbiotic relationship between plants and microbes by showing plants and microbes as circles and connecting organisms that have a friendly symbiotic relationship with each other with lines.

[0048] By the above method, among the soil microorganisms constituting the soil microflora at or near the planned site and the candidate trees for the high-rise trees, the high-rise trees that constitute the highest layer (forest canopy) of the ecosystem to be formed at the planned site and the soil microorganisms that can establish a symbiotic relationship beneficial to the growth of the high-rise trees are identified. For example, if a literature survey is used as the analysis method, the high-rise trees and the microorganisms that can serve as supporting organisms are determined by obtaining literature that identifies microorganisms that have been recognized to have a relationship with the candidate high-rise trees, particularly a beneficial symbiotic relationship such as a growth-promoting effect. Alternatively, the soil microorganisms contained in the collected sample are compared with a microbial database to see whether they can establish a beneficial symbiotic relationship with the candidate high-rise trees, and the high-rise trees and the microorganisms that can serve as supporting organisms are selected. In addition, the selection may be made by conducting microbial experiments such as an inoculation test in which a culture of soil microorganisms (particularly non-mycorrhizal filamentous fungi) isolated from the collected sample is inoculated into the candidate high-rise trees to examine the effect on their growth, or an in-ground culture test to examine the antagonistic and pesticidal effects of the candidate high-rise trees against disease-causing bacteria.

[0049] The support organisms may be microorganisms other than those constituting the soil microflora of the proposed site or its neighboring ecosystem. For example, the support organisms may be general soil microorganisms that are present in various regions but are present in small amounts in the soil microflora of the proposed site or its neighboring ecosystem, and that can contribute to the establishment of tall trees at the proposed site.

[0050] In addition, plants that can help the growth of tall trees may be used as supporting organisms. For example, shrubs and herbaceous plants that protect the root zone of tall trees by covering the ground, green manure plants that fix nitrogen and provide a nitrogen source for tall trees, and plants that build a symbiotic relationship with tall trees through soil microorganisms may be used as supporting organisms.

[0051] There may be two or more kinds of supporting organisms, and soil microorganisms and plants may be used as supporting organisms. Examples of plants that can be used as supporting organisms include medium-sized shrubs that are not tall trees (i.e., other than tall trees and sub-tall trees), herbaceous plants, and vines and creepers. In this specification, medium-sized shrubs, herbaceous plants, and vines and creepers that are not tall trees are referred to as "medium-sized and low-sized plants." In particular, plants that can establish a beneficial symbiotic relationship with tall trees through specific soil microorganisms (referred to as "intermediate microorganisms") (referred to as "rhizosphere symbiotic plants") are preferably used as supporting organisms. Rhizosphere symbiotic plants can be allowed to establish a symbiotic relationship with the intermediary microorganisms, and introduced into artificial green spaces together with or before the tall trees.

[0052] In this embodiment, it is assumed that the white oak is identified as a high-rise tree, and the shrub trees Nandina and Forsythia, and the herbaceous plants Iris japonica and Oxalis are identified as supporting organisms. In addition, the filamentous fungus A, which is an endophytic fungus, is also identified as a supporting organism. Although the filamentous fungus A has a small composition ratio in the soil microflora of the planned site, it symbiotically lives on the roots of the white oak and the Nandina in the natural ecosystem near the planned site, and the symbiotic relationship analysis shows that it has established a symbiotic relationship with all of the white oak, the Nandina, Forsythia, Oxalis, and Iris japonica, and that these plants can establish a plant-microbe symbiotic network in the soil through the filamentous fungus A. That is, in this embodiment, the filamentous fungus A is an intermediate microorganism, and the Nandina, Forsythia, Oxalis, and Iris japonica are rhizosphere symbiotic plants.

[0053] In this embodiment, an artificial green space is formed in which a herbaceous community is first formed, followed by a shrub community, and then, after 10 to 20 years, a vegetation transition occurs leading to a climax forest in which Quercus serrata with a tree height of about 10 m forms the canopy. High-rise trees and mid- to low-rise plants can establish a symbiotic relationship with the filamentous fungus A by extending their roots in the culture soil containing the filamentous fungus A.

[0054] In this embodiment, Oxalis grown in culture soil containing the fungus A is planted from autumn to winter so as to cover the entire planned site. The following spring, Iris japonica grown in culture soil containing the fungus A is planted at intervals of about 20 to 30 cm so as to be scattered throughout the planned site. When planting Iris japonica, or after planting Iris japonica, young seedlings of Quercus myrsina, Nandina and Forsythia with a height of about 20 to 30 cm grown in culture soil containing the fungus A are planted at intervals of about 2 to 3 m so as to be scattered throughout the planned site. The culture soil containing the fungus A is prepared by adding a strain of the fungus A isolated from a field sample, cultured and stored, grown in culture soil (bacteria bed) for fungal growth, and then adding the resultant to the culture soil for plant growth.

[0055] In the proposed site, an annual herbaceous community dominated by Oxalis will first appear, followed by a perennial herbaceous community dominated by Iris serrata. The Iris serrata community contains tree seedlings such as Quercus myrsinae, Nandina and Forsythia, and as these tree seedlings grow, a shrub community dominated by Nandina and Forsythia will appear, and then a climax forest will emerge in which the grown Quercus myrsinae will form the canopy.

[0056] These vegetation successions are artificially induced by considering the relationship between the plants that are dominant in each succession stage. In particular, in this embodiment, the plants that are dominant in each succession stage are configured to construct a plant (root)-soil microorganism symbiotic network underground via an intermediate microorganism (filamentous fungus A). Specifically, plants that have established a symbiotic relationship with filamentous fungus A, which is identified as a key microorganism (intermediate microorganism) that constructs a symbiotic network connecting the plants to be introduced to the planned site, are introduced to the planned site.

[0057] In this manner, in this embodiment, the soil microflora of the natural ecosystem at or near the planned site is understood, and plants that are compatible with the soil microflora of the planned site, i.e., plants that can build a good symbiotic relationship with the soil microorganisms of the planned site, can be selected. Therefore, it is possible to design, by backcasting, the plant community that is to be artificially formed at the planned site (a Quercus myrsinae community) rather than the ecosystem that is naturally formed at the planned site (a Quercus glauca community in this embodiment).

[0058] Fig. 3 shows the plant species that make up the Diagram-Quercus glauca community and Quercus myrsinae community that will naturally form at the planned site. The climax forest formed in this embodiment is a plant community in which Quercus myrsinae is the dominant tall tree, Nandina and Forsythia make up the shrub layer, and Iris japonica makes up the herbaceous layer, and is different from the plant community that will form at the planned site under natural conditions.

[0059] Unlike plant communities that are formed in a natural environment, plant communities that are artificially formed and designed with backcasting thinking generally require management to avoid damaging the plants that make up the community, and if they are damaged, they need to be replanted. Tall trees that are over 3m or even 5m tall are particularly difficult to obtain and plant. Furthermore, if such tall trees are damaged after being planted in an artificial green space, the intended landscape cannot be formed, and planting new trees to replace the damaged trees involves the risk of damaging buildings and costs.

[0060] According to the present invention, by introducing supporting organisms that can build beneficial symbiotic relationships with the tall trees that make up the artificial green space, it is expected that the robustness of the plant communities that make up the artificial green space will be improved. Therefore, according to the present invention, the management of the artificial green space can be eliminated or simplified, and in particular, the risk of damaged plants occurring and the cost of replanting can be reduced.

[0061] In particular, according to the present invention, the risk of damage to plants introduced into artificial green spaces designed and formed using backcasting thinking, particularly tall trees with heights of 3 to 5 m or more that are difficult to plant after construction, can be reduced. Furthermore, if vegetation succession is artificially induced in the construction site of an artificial green space as in this embodiment, young trees that are inexpensive, easy to obtain and handle can be used even when forming a tall forest, reducing the cost of forming the artificial green space. Furthermore, because it is possible to design a changing landscape, it is expected that the interest of residents in the artificial green space will be increased.

[0062] For example, potted tree seedlings may be provided to apartment residents at their request, and the residents may cultivate them for a certain period of time and then plant them in the artificial green space. If the seedlings cultivated by the residents are introduced into the artificial green space at a specified time (for example, on the 5th anniversary of moving in), it is expected that the residents' attachment to the artificial green space will increase. In addition, by using culture soil containing intermediary microorganisms as the culture soil for the potted plants provided to the residents, the establishment and growth of the tree seedlings transplanted into the artificial green space can be promoted.

[0063] Next, a second embodiment of the present invention will be described. In the second embodiment, a roadside tree belt is constructed as an artificial green space between the roadway and the sidewalk, with dogwoods and azaleas planted, in conjunction with the construction of a new road. In the second embodiment, soil and plant roots from the mixed forest that existed on-site before the construction of the new road are collected and environmental DNA analysis is performed. After that, soil is collected from the area where roadside trees are to be planted on the side of the newly constructed road, and environmental DNA analysis is performed.

[0064] The environmental DNA analysis identifies filamentous fungus B, an endomycorrhizal fungus that is a microorganism capable of establishing a symbiotic network with both dogwood and azalea, as a supporting organism and was present in the sample subjected to the environmental DNA analysis. In a second embodiment, culture soil containing filamentous fungus B is poured around the root zone of the dogwood and azalea to be planted, and seedlings of the dogwood and azalea are planted.

[0065] According to this embodiment, when the planted dogwood and azalea grow their roots, they can receive nutrients and water from the filamentous fungus B by establishing a symbiotic relationship with the filamentous fungus B contained in the culture soil. This relieves the stress associated with planting, promotes growth, and reduces the risk of damage such as withering.

[0066] As described above, according to the present invention, the risk of damage to tall trees that make up an artificial green space can be reduced, and the costs of forming, maintaining and managing the artificial green space can be reduced.

[0067] Next, a third embodiment of the present invention will be described. In the third embodiment, a case where a method for artificially constructing an ecosystem is carried out will be described using a proposed site for modification of about 300 m×300 m shown in FIG. 4 as an example.

[0068] The area proposed for conversion includes a residential lot of approximately 1,000 square meters (the area around the area marked "House" in Figure 4), farmland surrounding the residential lot, and abandoned forest (bamboo forest, scrub forest, and cedar forest) behind the farmland. On the other side of the road from the residential lot is a flat rice paddy area.

[0069] The cedar forests facing each other across the stream are terraced, and the terrain between these cedar forests (hereafter referred to as "terraced rice forests"), the residential land, the farmland, and the valley stream is flat, while the other forests (bamboo forests, mixed forests, and cedar forests facing the road) are slopes. In this embodiment, the bamboo forests, mixed forests, cedar forests (including terraced rice forests) and flat land along the valley stream (total of about 60,000 square meters) shown in Figure 4 are considered for modification.

[0070] The attributes of the proposed redevelopment sites are first identified in terms of their location and topography. Specifically, the location is identified by its climate zone and potential natural vegetation, and then based on the distance from residential and agricultural land (collectively referred to as "village"), the site is classified as "adjacent to village" within 30 meters of the village's outer edge in a straight line, "adjacent to village" within 50 meters, "buffer zone" within 70 meters, or "natural zone" further than 70 meters.

[0071] The proposed modification area in this embodiment is located in the northern mountainous region of Oita Prefecture, and the potential natural vegetation includes communities of Ardisia crenata and Ardisia japonica, communities of Castanopsis cuspidata and communities of Japanese yew, and is classified as adjacent to human settlements, adjacent to human settlements, buffer areas, and natural areas depending on the location. Of this proposed modification area, the adjacent to human settlements and adjacent to human settlements are designated as proposed modification areas, and the topographical attributes of the proposed modification areas are identified. The topography is classified as flat with a gradient of less than 8 degrees, slopes of 8 degrees or more, gentle slopes of less than 20 degrees, steep slopes of 20 degrees to 35 degrees, and extremely steep slopes of 35 degrees or more. In the proposed modification area in this embodiment, the terraced rice fields and the valley streams are flat, while most of the other forests are gentle slopes, with some steep slopes.

[0072] The ecosystems currently existing in the proposed redevelopment area (existing ecosystems) are forest ecosystems and herbaceous ecosystems, and the state of human management is almost entirely abandoned. When combined with classifications based on vegetation, the types are classified as abandoned bamboo forests, abandoned mixed forests, abandoned cedar forests, and semi-managed herbaceous ecosystems (Miscanthus sinensis-Sophora altissima-Mallotus japonica herbaceous community).

[0073] In this embodiment, the value of the existing ecosystem is evaluated by quantifying its supply function, carbon dioxide absorption and fixation function, and natural disaster protection function. Since the existing ecosystem is not used for the production of agricultural and forestry products, if the current situation is maintained, the value based on the supply function for the next 30 years is calculated to be zero. In addition, the age of the abandoned cedar forest is over 50 years, and if the current ecosystem is left as it is, the value based on the carbon dioxide absorption and fixation function for the next 30 years is calculated to be zero or negative.

[0074] Furthermore, if the status quo is maintained for the next 30 years, the abandoned bamboo forests will expand, their root systems will weaken, and the overplanted cedar trees will be at a higher risk of collapsing, so their value based on natural disaster protection functions will be zero or negative.

[0075] Therefore, it was decided to alter approximately 1,200 square meters of land adjacent to the human settlement, approximately 5,000 square meters of terraced rice fields and flat land along the stream, and approximately 800 square meters of land adjacent to the human settlement. In particular, it was decided that a total of approximately 6,200 square meters of land adjacent to the human settlement, including the terraced rice fields and flat land along the stream, would be made available for artificial use as a solar power generation site.

[0076] The solar power generation facility will have a system capacity of 380 kW. The value gained from this power generation (non-ecosystem value) will be 3.8 million yen per year if the electricity is sold at 10 yen / kWh.

[0077] The existing ecosystem on this approximately 7,000 square meter site was cut down and the soil was made bare, and plant residues resulting from the cutting down of the existing ecosystem were introduced as a carbon source. In addition, plant residues from nearby farmland were buried or laid in the proposed site for five years after the conversion to strengthen the soil formation function. The soil formation function for five years after the conversion was evaluated as the productivity of producing agricultural materials (compost) from the plant residues introduced. In this embodiment, 3,000 kg of agricultural materials (compost) were produced per year in the proposed site of approximately 7,000 square meters, and the value was calculated to be approximately 300,000 yen per year.

[0078] Then, after five years from the alteration, 20% of the planned alteration site will be used to produce agricultural materials (compost), while the remaining part will be used to create an agricultural ecosystem that produces agricultural and forestry products. If orchid leaves are to be cultivated primarily in the agricultural ecosystem, then after five years from the alteration, the artificial ecosystem in the planned alteration site will produce approximately 60,000 yen worth of agricultural materials and approximately 960,000 yen worth of agricultural products (orchid leaves), and the value of the material supply function has been calculated to be approximately 1 million yen per year.

[0079] The power generation business on the proposed site will continue for 20 years after the conversion, and after that, an agricultural ecosystem or a managed woodland ecosystem for mushroom cultivation and mushroom tree production will be constructed on the proposed site. The value based on the supply function of 5,000 square meters of flat land when an agricultural ecosystem is constructed on the proposed site has been calculated to be approximately 1 million yen per year. Additionally, the value based on the supply function of a managed woodland ecosystem has been calculated to be approximately 300,000 yen per year.

[0080] Additionally, if at least 4,500 kg of organic matter is introduced to the proposed site per year for 30 years after the proposed site is remodeled, it has been calculated that the amount of carbon dioxide absorbed and fixed in the future ecosystem will be at least 600 kg of CO2 per year. Note that instead of plant residues, another carbon source, such as carbonized material (bamboo charcoal or other wood charcoal), may be introduced to the proposed site. Carbonized material is a porous carbon source, and its introduction can enhance ecosystem functions such as increasing the amount of carbon dioxide absorbed and fixed, providing a habitat for soil organisms, and increasing water retention.

[0081] As stated above, it was shown that the value of maintaining the current ecosystem as it is for the next 30 years will be zero or negative.On the other hand, it was confirmed that if the current ecosystem were to be eliminated temporarily and used as a solar power generation site while constructing multiple ecosystems (future ecosystems) of different types from the current ecosystem, the value gained from the future ecosystems would exceed 20 million yen in 30 years after the modification based on the value based on the supply function alone, and that the value based on the soil formation function and carbon dioxide absorption and fixation function would also exceed that of the current ecosystem for the next 30 years.

[0082] In addition, by putting the proposed site to artificial use for solar power generation (not ecosystem use, non-ecosystem use), it was estimated that the non-ecosystem use value over a 20-year period after the conversion would be 76 million yen.

[0083] In this embodiment, in order to promote the construction of an ecosystem (thriving vegetation) in the proposed remodeled land after the end of solar power generation, the physical, chemical and biological properties of the soil are improved. Specifically, as described above, a carbon source such as organic matter (plant residues) is introduced into the proposed remodeled land soil after remodeling, and microorganisms that contribute to the construction of the future ecosystem are introduced.

[0084] More specifically, the soil before modification is collected, and the soil microbial flora is analyzed. Microorganisms contained in the sample are isolated and identified using a general microbial culture medium (such as PDA medium). Measurement of organic matter and analysis of the soil microbial flora can be performed using general methods such as the ignition loss method and environmental DNA analysis.

[0085] Using microbiota analysis, microorganisms that are beneficial for constructing a future ecosystem (e.g. beneficial for cultivating foliage orchids) are identified from the microorganisms isolated and strained from the sample. Then, the strained microorganisms are introduced into the proposed site by incorporating cultures of the strained microorganisms into organic matter (e.g. pruned branches or plants to be planted) to be put into the proposed site after the modification. The promotion of the construction of an ecosystem using such microorganisms is in accordance with the first embodiment.

[0086] As described above, according to the present invention, an ecosystem with a declining ecosystem service evaluation value can be modified and used for artificial purposes that generate immediate economic value, while at the same time creating soil that is beneficial for constructing an ecosystem different from the current ecosystem after the artificial use is completed. In this way, according to the present invention, it is possible to create value 20, 30, or even 50 years from now while using the land to be modified in a way that meets the social needs at the time of modification, achieving both economic efficiency and environmental conservation, and achieving both short-term profits and long-term asset construction.

[0087] In other words, according to the present invention, when modifying an ecosystem, it is possible to use the ecosystem in a way that meets the current social needs, while at the same time building the foundations of an ecosystem that responds to changes in social conditions 20 to 30 years from now and meets future needs 20 to 30 years from now.

[0088] Furthermore, a fourth embodiment of the present invention will be described. In the fourth embodiment, two opposing forested slopes in the eastern region of Hokkaido, each about 300 m wide and 150 m high, and a flat area (about 300 m square) located between the slopes and formed by filling in a valley with collapsed soil and other materials, are set as disturbed areas for artificially constructing an ecosystem. The forested slopes have lost their vegetation due to the collapse of the slopes, and buried soil has accumulated on the flat areas, leaving both areas bare.

[0089] The disturbed area is bare, but there is a natural ecosystem in the area (within 5 km) surrounding the disturbed area that still retains the vegetation from before the disaster. A vegetation survey of the disturbed area and the natural ecosystem in the surrounding area and an analysis of the soil microbial (filamentous fungi) flora confirmed that pine seedlings live in symbiosis with mycorrhizal fungi in the disturbed area and in the surrounding area. Furthermore, environmental DNA analysis confirmed that in addition to mycorrhizal fungi, the soil microbial flora in the disturbed area and in the surrounding area also contains non-mycorrhizal fungi that are beneficial to the growth and disease-causing fungi in pine trees. Some of the non-mycorrhizal fungi were isolated and cultured using PDA medium or oatmeal medium, which are common microbial culture media, without allowing them to live in symbiosis with plants.

[0090] The disturbed slopes were to be regenerated as forests mainly consisting of larch trees, which had been planted in the disturbed areas before the disaster. Larch trees were planted as both planted trees and lead plants, and mycorrhizal fungi, which coexist with larch trees and help them grow, were selected as the intermediary microorganisms (first intermediary microorganisms). Then, in the denuded parts of the disturbed slopes that were judged to be difficult to restore to natural vegetation (approximately 50m square in the center of the slope), soil blocks (approximately 20cm wide x 10cm long, approximately 15cm thick) cut from land adjacent to the disturbed area were scattered at intervals of approximately 5m. The soil blocks were natural soil blocks containing pine seedlings as lead plants that coexist with mycorrhizal fungi, the first intermediary microorganisms.

[0091] Several years (1-5 years) after placing the soil blocks on the disturbed land (slope), the larch seedlings are introduced as planted trees by rooting them in culture soil in which non-mycorrhizal filamentous fungi (endophytic fungi) isolated and cultured from the disturbed land or nearby areas have been grown as second intermediary microorganisms. It is preferable to use container seedlings that have been rooted in a container filled with culture soil containing the second intermediary microorganisms as the planted trees.

[0092] In this embodiment, a herbaceous green manure plant (pumpkin) is introduced as a lead plant in the disturbed ground horizon. The pumpkin coexists with nitrogen fixing bacteria as the first intermediary microorganism. Pumpkin cultivation is carried out at least once a cycle, preferably 2 to 3 cycles, and the pumpkin is allowed to coexist with the nitrogen fixing bacteria while observing its growth. The disturbed ground horizon is divided into an area for cultivating general agricultural crops (agricultural land), an area for nursery growing larch seedlings, and an area for extensive agriculture and forestry. After the cultivation of pumpkin as a lead plant is completed, planted trees that have artificially coexisted with the second intermediary microorganism are cultivated in the area for nursery and the area for extensive agriculture and forestry.

[0093] In addition, a woody green manure plant (Japanese anemone) is introduced on the slopes and in the areas where extensive agriculture and forestry are carried out. The larch seedlings contained in the soil blocks are introduced as lead plants, and on the slopes where the larch seedlings are introduced as planted trees after the soil blocks are placed, two types of planted trees are introduced: the larch is the first planted tree and the Japanese anemone is the second planted tree. The order of the Japanese anemone and the larch seedlings as planted trees can be either one after the lead plant is introduced. Japanese anemone can also be introduced on slopes where larch is not introduced as a lead plant, and then another tree (e.g., fruit trees such as blueberries) that is easy to use commercially but prefers fertile soil can be introduced as a planted tree. In this case, it is recommended that nitrogen-fixing bacteria as the first intermediary microorganism coexist with the Japanese anemone, and that the second intermediary microorganism is selected from indigenous non-mycorrhizal filamentous fungi and coexist with the planted trees.

[0094] In this embodiment, the planted tree seedlings are grown in a flat surface where a pumpkin is introduced as a lead plant, using a culture medium in which a second intermediary microorganism is grown. As the second intermediary microorganism, a non-mycorrhizal filamentous fungus that can establish a friendly symbiotic relationship for both the planted tree and the lead plant and is easy to isolate, grow, and culture is preferably used, and in particular, an indigenous non-mycorrhizal filamentous fungus that constitutes the soil microflora of disturbed areas or areas nearby is preferably used. As the second intermediary microorganism, it is particularly preferable to use, among non-mycorrhizal filamentous fungi, filamentous fungi that are particularly friendly to various plants, such as filamentous fungi of the genus Trichoderma or Morteria.

[0095] When selecting an indigenous non-mycorrhizal fungus as the second intermediary microorganism, it is preferable to conduct a microbial experiment on the isolated indigenous non-mycorrhizal fungus. Specifically, when a culture of the non-mycorrhizal fungus is placed in the rhizosphere of a planted tree to artificially allow it to coexist with the plant, it is recommended to test whether beneficial effects such as germination, rooting, and growth promotion are observed, or whether there is an antagonistic effect against disease-causing bacteria are observed. Furthermore, it is recommended to conduct an experiment to confirm that there is no adverse effect on the growth of a reed plant when the fungus is introduced into the rhizosphere of the reed plant that coexists with the first intermediary microorganism.

[0096] In this embodiment, the second mediator microorganism is a filamentous fungus of the genus Mortella, which was isolated from soil near the disturbed area and was found to have a growth-promoting effect on a wide range of plants through analysis and inoculation tests. The second mediator microorganism is artificially allowed to coexist with the larch seedlings, and cuttings or seedlings are rooted and germinated in culture soil containing the second mediator microorganism. The containerized larch seedlings artificially allowed to coexist with the second mediator microorganism are then grown on the disturbed ground plane and introduced onto a slope as planted trees.

[0097] By making seedlings in this way, the second intermediary microorganism is also artificially introduced into the disturbed ground horizon. That is, pumpkins as lead plants and nitrogen-fixing bacteria as the first intermediary microorganism are introduced into the disturbed ground horizon, and then the second intermediary microorganism is artificially introduced when making seedlings. This second intermediary microorganism is an indigenous microorganism and a non-mycorrhizal filamentous fungus that is friendly to a wide range of plants, so it can contribute to improving the biological quality of the nursery soil. Therefore, when a nursery is converted into farmland to cultivate crops, it is expected that the second intermediary microorganism will coexist with the cultivated crops and promote their growth, making it possible to regenerate farmland with less of a burden on "soil making."

[0098] In addition, a first mediator microorganism (mycorrhizal fungus) is introduced on the slope of the disturbed area by arranging soil blocks containing a reed plant (larch), and then a larch seedling with a second mediator microorganism (non-mycorrhizal filamentous fungus) artificially living in symbiosis is introduced as a planted tree. As the second mediator microorganism, a microorganism that can coexist amicably with both the reed plant and the planted tree is selected, and the reed plant introduced prior to the planted tree supports the establishment and growth of the planted tree. By using plants that grow easily in harsh environments (thin soil, extreme dryness and wetness, low nutrients and moisture, difficult absorption, etc.) and plants that grow quickly (for example, herbaceous plants and green manure plants) as reed plants, the vegetation of the disturbed area that has become bare can be quickly restored with a small amount of planting (i.e., low cost), and a growth base for trees that are more difficult to establish than the reed plant can be created. Therefore, according to this embodiment, it is possible to achieve faster vegetation recovery compared to leaving the disaster area while reducing the cost of vegetation recovery.

Claims

1. A method for artificially constructing an ecosystem in a disturbed area, comprising: A lead plant capable of symbiosis with an intermediary microorganism capable of establishing a friendly symbiotic relationship with a planted tree, which is a tree to be planted in the disturbed area, is introduced into the disturbed area, and the lead plant is allowed to symbiotically coexist with the intermediary microorganism in the root zone of the lead plant; A method for artificially constructing an ecosystem, comprising introducing the lead plant into the disturbed area and then introducing the planted trees.

2. The planted trees are indigenous tree species selected from potential vegetation species that constitute the potential natural vegetation of the area in which the disturbed land is located, or from native tree species that grew in the disturbed land or in the vicinity thereof before the disturbance of the disturbed land, 2. The method for artificially constructing an ecosystem as described in claim 1, wherein the intermediary microorganism is a filamentous fungus contained in the soil microflora of either or both of the disturbed area and the surrounding area, and the planted tree or the lead plant is introduced into the disturbed area in a state in which the planted tree or the lead plant is symbiotic with the intermediary microorganism in its rhizosphere.

3. 3. A method for artificially constructing an ecosystem as described in claim 1 or 2, wherein the reed plant is introduced into the disturbed land by scattering a plurality of reed plant blocks containing the intermediary microorganism and the reed plant in the disturbed land.

4. 4. The method for artificially constructing an ecosystem according to claim 1 or 3, wherein the reed plant is a green manure plant that establishes a symbiotic relationship with nitrogen fixing bacteria as an intermediary microorganism.

5. The lead plant is a mycorrhizal symbiotic tree that establishes a symbiotic relationship with mycorrhizal fungi as an intermediary microorganism, 4. The method for artificially constructing an ecosystem as described in claim 3, wherein the reed plant block is a natural soil block cut from a natural ecosystem in the vicinity of the disturbed area in which the reed plant has established a symbiotic relationship with mycorrhizal fungi, or an artificial plant block in which a symbiotic relationship between the reed plant and mycorrhizal fungi has been artificially established.

6. The intermediate microorganism is an indigenous non-mycorrhizal filamentous fungus that is contained in the soil microflora of either or both of the disturbed area and the adjacent area and that establishes a symbiotic relationship with plants through hyphae without forming mycorrhizae, 6. A method for artificially constructing an ecosystem according to claim 1, wherein the planted trees are grown in soil containing a culture of the mediator microorganism and then introduced into the disturbed land.

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