Methods for artificially constructing 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 an artificial construction method for ecosystems.

BACKGROUND ART

[0002] Conventionally, ecosystems have been artificially utilized and modified, but in some cases, ecosystems are placed in a state where their functions cannot be fully exerted, or the utilization and modification of ecosystems are performed in a manner that impairs the functions of the ecosystems. For example, abandoned cultivated lands and devastated forests (neglected forests) can be cited as examples where the production function of ecosystems that used to demonstrate rich productivity through appropriate human utilization is no longer exerted. Another example of the latter case is agricultural ecosystems where soil has been degraded by excessive cultivation, leading to reduced productivity. Disturbed lands that have lost vegetation and become bare due to construction works for houses, condominiums, buildings, roads and other structures, as well as sediment-related disasters, can also be regarded as lands where the functions of the ecosystem are impaired.

[0003] Artificial construction of ecosystems on lands where the functions of the ecosystem are not exerted in this way has also been conventionally carried out. For example, artificial green spaces with artificially restored vegetation have been constructed on bare lands that have lost vegetation due to urban development and the like. In particular, a large number of construction works have been carried out in urban areas, and various artificial green spaces have been constructed, while natural ecosystems such as mountainous areas are scarce.

[0004] Conventionally, artificial green spaces in urban areas have been designed to have an urban aesthetic appearance, and have been constructed such that the designed artificial green spaces are completed upon the completion of construction works. In recent years, as such urban artificial green spaces, artificial green spaces having landscapes and functions close to natural ecosystems (for example, biodiversity conservation function) have been in demand. In order to construct an artificial green space having a landscape and functions close to a natural ecosystem, it is preferable to plant a plurality of trees that grow to a certain height. Conventionally, when constructing an artificial green space, trees that have grown to a height of several meters are planted to complete the construction of the artificial green space.

[0005] In artificial green spaces constructed in urban areas in this manner, natural regeneration of trees is usually unlikely. Therefore, if trees are damaged, such as dying after construction, new trees need to be planted. However, it has been pointed out that planting trees several meters tall after the completion of construction of an artificial green space in an urban area is costly (Patent Document 1).

[0006] Patent Document 1 addresses the above problem by proposing a method for constructing artificial green spaces in urban areas that involves creating multiple vegetation types leading up to climax forests, thereby improving the natural recovery capacity of the vegetation in the artificial green spaces after construction.

[0007] In recent years, there have been concerns that renewable energy (primarily solar power), for which demand is increasing in order to realize a decarbonized society, may be developed in a way that damages the functions of the natural ecosystems that originally existed in the development area. For this reason, when developing power plants, the ecosystems of the planned development site and its surroundings are sometimes surveyed, and measures are taken to preserve them.

[0008] Furthermore, with the recent increase in earthquakes, heavy rain damage (floods, landslides, etc.), wildfires, and other natural disasters, the artificial reconstruction of ecosystems is required in disaster-stricken areas. Examples of artificial ecosystem reconstruction carried out as part of disaster recovery include the restoration of agricultural and forest land and the greening of slopes along restored roads. In the artificial reconstruction of ecosystems as part of disaster recovery, there are cases where efforts are made to restore the ecosystem to its pre-disaster state so that agriculture, forestry, and daily life can be carried out in the same place as before the disaster. However, because disasters also trigger population movement (migration), there are cases where ecosystems such as agricultural and forest land that have been restored at great cost are not utilized to the extent that the investment was made. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2018-42527 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] The method described in Patent Document 1 involves arranging community rings consisting of climax forests and plant communities in the process of succession leading to the climax forests in multiple green spaces scattered over a wide area. In this way, arranging artificial green spaces that form community rings leading to climax forests across multiple plots of land requires obtaining the consent of each landowner or manager, which is time-consuming and costly.

[0011] Furthermore, if an ecosystem of high ecological value exists in a power plant development site, even if environmental conservation measures are taken during power plant development, some degree of decline in the value and function of the ecosystem is unavoidable. It should be noted that high ecological value means a high evaluation of ecosystem services, that is, the ecosystem performs many or many beneficial functions, such as conserving diverse organisms, providing habitats for rare plants and animals, having a large capacity to absorb carbon dioxide, having high productivity for agricultural and forestry products, and having high soil erosion prevention and water retention functions.

[0012] Thus, when an ecosystem has high value before human use or modification, it requires considerable effort to avoid a decline in its value due to human use or modification. Therefore, investing effort in ecosystem conservation increases development costs, while not investing effort leads to a decline in the ecosystem's value, making it difficult to reconcile economic viability with environmental conservation.

[0013] Alternatively, when artificially constructing ecosystems as part of disaster recovery, particularly when restoring agricultural and forestry land, it is believed that if ecosystems are artificially constructed with minimal human effort (cost), taking into account population movement after the disaster, and if the restored agricultural and forestry land can be utilized and managed with less human effort (cost) than before the disaster, the recovery of the affected areas can be facilitated.

[0014] This invention provides a method for creating artificial green spaces that reduces the cost of replacing damaged trees after construction and allows for the construction of artificial green spaces with trees reaching a height of 3 to 5 meters or more, even on a single plot of land that is not large in area. This invention also provides a method for artificially creating ecosystems that can benefit from changes over time.

[0015] The present invention further provides a method for avoiding the decline in the value of an ecosystem when it is artificially used or modified. In particular, it provides a method for artificially constructing an ecosystem that has been modified for artificial use, thereby modifying an ecosystem whose function (value) has declined, and constructing a higher-value ecosystem while increasing the productivity and use value of the land in which the ecosystem exists.

[0016] The present invention also provides a method for artificially constructing an ecosystem that can reduce the cost of restoring land (disturbed land) that has been damaged by natural disasters and lost its vegetation. [Means for solving the problem]

[0017] In a first aspect of the present invention, with respect to tall trees that constitute a forest in an artificial green space, support organisms that are compatible with the tall trees in the artificial forest are identified, and the support organisms are introduced into the artificial green space at the same time as or prior to the introduction of the tall trees.

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

[0019] In this specification, a stable plant community formed by tall trees designated as the highest-rise trees to be introduced into an artificial green space is referred to as a "climax forest." A "stable plant community" means a plant community that is maintained without the need for artificial planting of other plants.

[0020] In this specification, organisms that are compatible with tall trees (sometimes referred to as "support organisms") refer to organisms that have established a symbiotic relationship beneficial to the growth of tall trees, particularly plants, microorganisms, or both. A "symbiotic relationship beneficial to the growth of tall trees" means a relationship that promotes the growth and establishment of tall trees, or enhances their tolerance to stresses such as drought, high temperatures, low temperatures, wind and snow, and other weather stresses, as well as pest and disease stress.

[0021] More specifically, examples include low-lying and mid-range plants and herbaceous plants that cover the base of tall trees to increase their resistance to weather stress; plants and microorganisms that produce repellent substances for insects that cause damage to tall trees, thereby reducing pest and disease stress on tall trees; and soil microorganisms that live symbiotically with the roots of tall trees to help them absorb nutrients and water.

[0022] When introducing herbaceous plants as support organisms into artificial green spaces, it is advisable to establish herbaceous plant communities where herbaceous plants are the dominant species before introducing tall trees into the artificial green space. In this way, artificially designed vegetation succession can be created on the same land, and by intentionally changing the plant communities over a period of years from the start of construction of the artificial green space, it is possible to induce changes in the artificially designed landscape over time.

[0023] In another aspect of the present invention, for land where an ecosystem exists that is not fully performing the functions it is capable of (low evaluation value of ecosystem services), a different type of ecosystem (future ecosystem) that can be constructed on that land is constructed. Specifically, the value of the ecosystem existing on the land before modification (existing ecosystem) is calculated, and the value that can be obtained from that land (future value) is calculated by constructing a different type of ecosystem (future ecosystem) from the existing ecosystem that can be constructed while the land is being artificially used. Then, the land is modified in order to construct a future ecosystem while using the land that will result in a higher future value for the land than the value that would result from the continued existence of the existing ecosystem.

[0024] The types of ecosystems can be broadly classified into, for example, forest ecosystems dominated by trees, herbaceous ecosystems dominated by herbaceous plants, and artificial ecosystems such as farmlands and parks where artificial planting is carried out and vegetation management is performed manually. The forest ecosystems and herbaceous ecosystems may be further typed by classifications according to the state of manual management and utilization (such as "untended", "semi-untended", and "managed") and classifications according to vegetation (such as "artificial forest", "bamboo forest", "evergreen tall tree forest", and "mixed coniferous-broadleaf forest").

[0025] The future ecosystem may be allowed to transition over a predetermined period after changing the existing ecosystem at the planned modification site. That is, the future ecosystem may include two or more ecosystems of different types. For example, in order to artificially transition from an ecosystem of a certain type (the first future ecosystem) to an ecosystem of another type (the second future ecosystem), a plant artificially symbiosed with microorganisms that have been isolated from the soil of the planned modification site and cultured, which contribute to the growth of plants desired to be dominant in the second future ecosystem, may be introduced into the planned modification site.

[0026] Thus, by introducing microorganisms beneficial to the construction of the future ecosystem into the planned modification site, the construction of the future ecosystem can be promoted, and improvement of the biological properties of the soil, particularly the diversity of the microbiota, can be expected. In addition, if a carbon source such as plant residues or carbides is introduced into the planned modification site in advance, the carbon source serves as a habitat and energy source for microorganisms, so that the improvement of the biological properties of the soil (one or both of an increase in biomass and an increase in biota diversity) can be promoted.

[0027] In the present invention, value assessment is performed on these various types of ecosystems. The value of an ecosystem can be evaluated, for example, by an evaluation method related to known economic value assessment of ecosystem services. The economic value assessment of ecosystem services may target and evaluate only a part of the ecosystem functions linked to the ecosystem services. When performing value assessment of part of the ecosystem functions, at least either the supply function of materials such as timber and food, which are supply services of the ecosystem, or the function related to carbon dioxide absorption and sequestration, which is a regulation service, preferably both, are evaluated. Both functions are easy to quantify as economic values. It is also preferable to evaluate at least one or more of the regulation services including water circulation control and natural disaster protection functions, and the foundational service of soil formation function.

[0028] The supply function may be quantified as the productivity (land productivity) when a certain material is produced, and the carbon dioxide absorption and sequestration function may be quantified as the carbon dioxide absorption and sequestration amount or the carbon dioxide emission trading price based thereon.

[0029] The value assessment of the existing ecosystem and the future ecosystem is preferably performed targeting the same functions, but different functions may be set as evaluation targets as long as a reasonable comparison can be made between the values of the existing ecosystem and the future ecosystem for a predetermined period after modification. For example, regarding the existing ecosystem and the future ecosystem, the values based on their respective highest-value functions (for example, the water circulation control function for the existing ecosystem, and the carbon dioxide absorption and sequestration function for the future ecosystem) may be used as evaluation targets for comparison. Alternatively, two or more different functions with high value for each ecosystem may be set as evaluation targets.

[0030] The value of existing and future ecosystems should be calculated for a period of at least 20 years, preferably 25 years, and more preferably 30 years, after modification. Since ecosystems that have been artificially modified tend to change easily for about 20 years, defining the management and utilization patterns of the modified ecosystem over a period of 20 to 30 years after modification makes it easier to construct the future ecosystem intended at the time of modification. Furthermore, after about 30 years, the differences between the current ecosystem and the economic and social conditions at the time of modification become apparent. For this reason, setting the predetermined period to 20 to 30 years makes it easier to consider whether or not to maintain the ecosystem constructed after modification once that period has elapsed, and to construct an ecosystem that is in line with the times.

[0031] Another aspect of the present invention is suitably used in disturbed areas where soil has been exposed (i.e., bare ground) due to the accumulation of sediment or the loss of previous vegetation caused by natural disasters, and realizes low-cost disaster area reconstruction (ecosystem restoration) by artificially utilizing the ecosystem-building and stabilizing power 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 will be artificially constructed, lead plants beneficial to the growth of said plants are introduced. The lead plants and planted trees may be the same species of plant, and green manure plants that coexist with nitrogen-fixing bacteria, mycorrhizal fungal symbiotic trees that coexist with mycorrhizal fungi, or artificially symbiotic trees in which non-mycorrhizal filamentous fungi are artificially coexisted can be used.

[0032] If the topsoil of the disturbed area has been eroded or sediment has accumulated, altering the topography and potentially changing drainage compared to before the disaster, it is preferable to use herbaceous green manure plants as lead plants. Herbaceous green manure plants grow quickly, can cover the surface of the disturbed area and prevent soil erosion, and their growth allows for assessment of the drainage quality of the disturbed area.

[0033] Furthermore, in cases where disturbed land is a slope prone to dryness, it is preferable to plant pioneer species of trees that can grow in nutrient-poor soil by forming a symbiotic relationship with mycorrhizal fungi, such as Alnus japonica or pine. However, artificially creating a symbiotic relationship between mycorrhizal fungi and trees requires special cultivation management techniques and materials. For this reason, when artificially constructing an ecosystem over a wide area, planting trees with artificially formed mycorrhizal fungi is not easy from a technical or cost perspective.

[0034] Therefore, in this invention, natural soil blocks extracted from natural ecosystems in disturbed areas or nearby areas (within 30 km, preferably 10 km, of the disturbed area; the same applies hereinafter in this specification) or artificial plant blocks in which mycorrhizal fungi are artificially coexisted with lead plants are scattered in the disturbed area. The blocks are preferably 10 cm to 40 cm thick, preferably 15 cm to 30 cm thick, with side lengths of 15 to 50 cm, preferably 20 to 30 cm (surface area of ​​200 to 2,500 square cm, preferably 300 to 500 square cm). The blocks are preferably arranged at intervals of 3 to 200 m, particularly at intervals of 5 to 10 m.

[0035] In this specification, "intermediary microorganisms" refer to microorganisms that can support the growth of lead plants and planted trees, which are introduced into disturbed areas prior to planting trees. As intermediary microorganisms, it is preferable to select microorganisms from among the soil microorganisms present in the disturbed area or its vicinity that exhibit friendly functions (i.e., promote growth, have disease control effects, etc.) with both the selected planted trees and lead plants, based on microbial analysis methods by Toju (described later), literature surveys, and microbial experiments such as inoculation tests. Non-mycorrhizal filamentous fungi found in the soil of the disturbed area or its vicinity are particularly favored as intermediary microorganisms. Among non-mycorrhizal filamentous fungi, those called endophytes enter the plant body and coexist with the plant, but do not form mycorrhizae. Non-mycorrhizal filamentous fungi include not only endophytes but also saprophytic fungi and soil fungi, which can be artificially cultured and propagated in general microbial culture media (such as oatmeal) without coexisting with plants. Therefore, by selecting non-mycorrhizal filamentous fungi that coexist with reed plants and are beneficial to the growth of planted trees from among the non-mycorrhizal filamentous fungi contained in the soil of disturbed areas and nearby areas, isolating and culturing these fungi, and then introducing the cultures into disturbed areas while artificially coexisting with reed plants and planted trees, the artificial construction of ecosystems can be made easier both technically and cost-effectively.

[0036] In this invention, when artificially constructing an ecosystem in disturbed land, the power of the natural ecosystem (specifically, indigenous microorganisms) is utilized. Therefore, when the restored ecosystem is used for agriculture and forestry, the soil microbial community of the restored area is utilized to bring out the ecosystem's ability to control pests and diseases and its stability, making it easier to conduct low-impact agriculture and forestry. [Effects of the Invention]

[0037] According to the present invention, by creating artificial vegetation succession that mimics the vegetation succession that can occur when an artificial green space is placed in a natural state, it is possible to create an artificial green space that reduces the effort and cost of replanting damaged trees. Furthermore, according to the present invention, it is possible to create an artificial green space that has a landscape and function similar to a natural ecosystem. Moreover, according to the present invention, it is possible to create an artificial green space that can be enjoyed as it changes over time.

[0038] Furthermore, according to the present invention, for example, neglected forests that are not properly managed, do not act as carbon dioxide sinks, and have reduced soil retention and rainwater retention functions due to soil exposure can be modified into solar power generation sites, and while generating solar power, a different ecosystem (a constructed ecosystem) can be built, thereby enhancing biodiversity conservation and soil retention functions.

[0039] Furthermore, according to the present invention, the difficulty of the technology and effort (cost) required for the artificial construction of ecosystems in disturbed areas such as disaster-stricken areas can be reduced, and disaster-stricken areas can be regenerated in a way that facilitates low-impact agriculture and forestry. [Brief explanation of the drawing]

[0040] [Figure 1] Examples of data obtained from environmental DNA analysis of soil microbiomes. [Figure 2] An example of analysis of symbiotic relationships between soil microbiota and plants (quoted from Toju, H. et al. Assembly of complex plant-fungus networks. Nature Communications 5:5273 DOI:10.1038 / ncommms6273(2014)) [Figure 3] Table showing plants that can naturally form a climax forest in an artificial green space according to the first embodiment of the present invention. [Figure 4] Schematic diagram showing the planned modifications for the third embodiment of the present invention. [Figure 5] Larch seedlings used as planting trees in the fourth embodiment of the present invention (seedlings without artificial symbiosis with non-mycorrhizal filamentous fungi; 2 pots on the left; seedlings with symbiosis; 2 pots on the right) [Modes for carrying out the invention]

[0041] Hereinafter, as a first embodiment of the present invention, we will describe an example in which a plot of land measuring 110m x 50m is assumed to be the planned site for an apartment building, and an artificial green space measuring 110m x 5m is formed thereon.

[0042] The planned site for the artificial green space (hereinafter referred to as the "planned site") is a disturbed area located in the inland part of the Kinki region, where the vegetation that existed before construction was lost due to construction work associated with residential land development. The area where the planned site is located is considered to be a region where the climax forest consists of a Siberian oak-Quercus community as its potential natural vegetation. In terms of climate zone, in addition to the Siberian oak-Quercus community in which Quercus acuta forms the canopy layer, this region can also form a climax forest with trees such as Quercus myrsinaefolia, Castanopsis sieboldii, Castanopsis cuspidata, and Quercus acuta forming the canopy layer.

[0043] Therefore, at the planned site, the following species will be considered as dominant species for the canopy layer of a forest stand (hereinafter referred to as "climax forest") that can be artificially constructed: Quercus glauca, Quercus myrsinaefolia, Castanopsis sieboldii, Castanopsis cuspidata, and Quercus acuta. One or more species will be selected from among these to be canopy trees. In this embodiment, when selecting canopy trees, the soil microbial community of the planned site will be referred to, and tree species that are compatible with the soil microbial community of the planned site, that is, tree species that can establish a good symbiotic relationship with the soil microbial community of the planned site, will be selected.

[0044] Specifically, soil samples will be collected from the planned site, as well as soil and plant roots from a nearby forest approximately 1 km away, representing the natural ecosystem. The collected soil and plant roots will be subjected to environmental DNA analysis. Environmental DNA analysis can be performed using standard methods, and a 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 constituting the soil microbiome and candidate tree species for tall trees will be analyzed. Methods for analyzing the symbiotic relationship between tall trees and soil microorganisms include literature reviews, comparison with microbial databases, and the analytical method described in Toju, H. et al. Core microbiomes for sustainable agroecosystems. Nature Plants 4 247-257 (2018) (hereinafter referred to as "Microbiome Analysis by Toju").

[0046] By analyzing the soil microbiome of the proposed site in this way, it is possible to understand what kinds of soil microorganisms are present at the proposed site. Furthermore, by analyzing the soil microbiome of the natural ecosystem near the proposed site, it is possible to understand the symbiotic relationships between the plants that make up the natural ecosystem near the proposed site and the soil microorganisms. In particular, if the natural ecosystem near the proposed site includes candidates for tall trees, by analyzing the symbiotic relationships between the organisms that make up that natural ecosystem, it is possible to identify soil microorganisms that have established good symbiotic relationships with candidate tall trees in that natural ecosystem, as well as soil microorganisms that are beneficial for introducing tall trees to the proposed site.

[0047] Figure 1 shows an example of soil microbiome analysis results using environmental DNA analysis. Figure 2 shows an example of analysis that examined the symbiotic relationship between plants and microorganisms from the microbiome analysis. Note that the microorganisms analyzed in Figures 1 and 2 are filamentous fungi and do not include bacteria. In Figure 1, for 16 samples, the abundance of DNA from groups of multiple microbial species contained in each sample is shown as a ratio. In Figure 2, plants and microorganisms are represented by circles, and organisms with friendly symbiotic relationships are connected by lines to illustrate the symbiotic relationship between plants and microorganisms.

[0048] Using the method described above, soil microorganisms constituting the soil microbiome of the planned site or its vicinity, along with candidate tall tree species, are identified to form the highest layer (canopy) of the ecosystem at the planned site, and to identify soil microorganisms that can establish a beneficial symbiotic relationship for the growth of these tall tree species. For example, if a literature search is used as the analytical method, the relationship between tall tree species and supporting microorganisms is determined by obtaining literature that identifies microorganisms that have been shown to have beneficial symbiotic relationships, particularly growth-promoting effects, with candidate tall tree species. Alternatively, the soil microorganisms contained in the collected samples are compared with candidate tall tree species using a microbial database to determine whether they can establish a beneficial symbiotic relationship, and the microorganisms that will support the tall tree species are selected. Furthermore, selection may be made by conducting microbial experiments such as inoculation tests, inoculation tests to examine the effect on growth of candidate tall tree species by inoculating cultures of soil microorganisms (especially non-mycorrhizal filamentous fungi) isolated from the collected samples, or ground culture tests to examine the antagonistic and control effects of candidate tall tree species against disease-causing fungi.

[0049] Support organisms do not have to be microorganisms that make up the soil microbial community of the planned site or its surrounding ecosystem. For example, a support organism could be a common soil microorganism that exists in various regions but is present in small quantities in the soil microbial community of the planned site or its surrounding ecosystem, and which can contribute to the establishment of tall trees in the planned site.

[0050] Additionally, plants that can help the growth of tall trees may be used as support organisms. For example, shrubs and herbaceous plants that protect the root zone of tall trees by covering the ground, green manure plants that supply nitrogen sources to tall trees by fixing nitrogen, and plants that establish a symbiotic relationship with tall trees through soil microorganisms can be used as support organisms.

[0051] Support organisms may consist of two or more species, including soil microorganisms and plants. Examples of plants used as support organisms include shrubs and herbaceous plants other than tall trees (i.e., trees and sub-tall trees), and climbing plants. In this specification, shrubs and herbaceous plants other than tall trees, and climbing plants are referred to as "mid- and low-rise plants." In particular, it is preferable to use plants that can establish a beneficial symbiotic relationship with tall trees through specific soil microorganisms (referred to as "mediating microorganisms") (referred to as "rhizosphere symbiotic plants") as support organisms. Rhizosphere symbiotic plants should be introduced into artificial green spaces together with or before tall trees after establishing a symbiotic relationship with mediating microorganisms.

[0052] In this embodiment, Japanese evergreen oak (Quercus myrsinaefolia) is identified as a tall tree, and shrub trees such as Nandina domestica and Forsythia suspensa, and herbaceous plants such as Iris japonica and Oxalis are identified as support organisms. Furthermore, filamentous fungus A, an endophytic fungus, is also identified as a support organism. Although filamentous fungus A makes up a small proportion of the soil microbiota of the proposed site, it lives in symbiosis with the roots of Japanese evergreen oak and Nandina domestica in the natural ecosystem near the proposed site. Symbiotic relationship analysis reveals that it establishes symbiotic relationships with all of Japanese evergreen oak, Nandina domestica, Forsythia suspensa, Oxalis, and Iris japonica, and that these plants can build a plant-microbe symbiotic network in the soil through filamentous fungus A. In other words, in this embodiment, filamentous fungus A is an intermediary microorganism, and Nandina domestica, Forsythia suspensa, Oxalis, and Iris japonica are rhizosphere symbiotic plants.

[0053] In this embodiment, an artificial green space is formed that creates a vegetation succession that starts with herbaceous plant communities, then develops into shrub communities, and after 10 to 20 years reaches a climax forest where Japanese evergreen oaks (Quercus myrsinaefolia) with a canopy of about 10m in height. Tall trees and mid-to-low-rise plants can establish a symbiotic relationship with filamentous fungus A by extending their roots in a growing medium containing filamentous fungus A.

[0054] Therefore, in this embodiment, oxalis grown in a growing medium containing filamentous fungus A is planted from autumn to winter to cover the entire planned site. In the following spring, irises grown in a growing medium containing filamentous fungus A are planted scattered throughout the planned site at intervals of about 20-30 cm. When planting the irises, or after planting the irises, young seedlings of Japanese evergreen oak, nandina, and forsythia, about 20-30 cm tall and grown in a growing medium containing filamentous fungus A, are planted scattered throughout the planned site at intervals of about 2-3 m. The growing medium containing filamentous fungus A is prepared by incorporating a strain of filamentous fungus A, isolated from a field sample, cultured and preserved, into a growing medium (substrate) for fungal growth, and then adding it to the growing medium for plant cultivation.

[0055] At the planned site, an annual herbaceous community dominated by oxalis will appear first, followed by a perennial herbaceous community dominated by iris. Within the iris community, tree seedlings such as Japanese evergreen oak, nandina, and forsythia will be included. As these seedlings grow, a shrub community dominated by nandina and forsythia will appear, and then a climax forest will emerge where mature Japanese evergreen oaks form the canopy.

[0056] These vegetation successions are artificially induced by considering the relationships between the dominant plant species at each successive stage. In particular, in this embodiment, the dominant plant species at each successive stage are designed to build a plant (root)-soil microbial symbiotic network underground via mediating microorganisms (filamentous fungus A). Specifically, plants that have established a symbiotic relationship with filamentous fungus A, which has been identified as a key microorganism (mediating microorganism) for building a symbiotic network connecting the plants to be introduced to the planned site, are introduced to the planned site.

[0057] Thus, in this embodiment, it is possible to understand the soil microbial community of the natural ecosystem in or near the planned site and select plants that are compatible with the soil microbial community of the planned site, that is, plants that can build a good symbiotic relationship with the soil microorganisms of the planned site. For this reason, it is possible to design the plant community that you want to create artificially (a Japanese evergreen oak community) rather than the ecosystem that is naturally formed in the planned site (in this embodiment, a Japanese evergreen oak community).

[0058] Figure 3 shows the plant species that make up the naturally formed slanted oak-Japanese evergreen oak community and Japanese white oak community in the planned site. The climax forest formed in this embodiment is a plant community in which Japanese white oak is the dominant tree, nandina and forsythia make up the shrub layer, and iris makes up the herbaceous layer, and it differs from the plant community that would be formed in the planned site under natural conditions.

[0059] Unlike plant communities that form naturally, plant communities designed and artificially created using backcasting thinking generally require management to avoid damaging the plants that make up the community, and replacement is necessary if damage occurs. In particular, tall trees exceeding 3m, or even 5m in height, are not easy to obtain or plant. Furthermore, if such tall trees are damaged after being planted in an artificial green space, the intended landscape cannot be formed, and planting replacement trees incurs the risk of damaging buildings and incurs costs.

[0060] According to the present invention, by introducing support organisms that can establish beneficial symbiotic relationships with tall trees that form artificial green spaces, it is expected that the robustness of the plant communities constituting the artificial green spaces can be improved. Therefore, according to the present invention, the management of artificial green spaces can be made unnecessary or simplified, and in particular, the risk of damaged plants 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, especially tall trees 3 to 5 meters or taller, which are difficult to plant after construction, can be reduced. Furthermore, by artificially inducing vegetation succession at the construction site of the artificial green space, as in this embodiment, it is possible to use inexpensive, readily available, and easy-to-handle saplings even when forming a forest of tall trees, thereby reducing the cost of forming the artificial green space. Moreover, because it is possible to design a changing landscape, it is expected that this will increase residents' interest in the artificial green space.

[0062] For example, in an apartment building, potted tree saplings could be provided to residents upon request, and after a certain period of cultivation by the residents, they could be planted in the artificial green space. Introducing the saplings cultivated by the residents into the artificial green space at a predetermined time (for example, to commemorate the 5th anniversary of their move-in) is expected to further increase the residents' attachment to the artificial green space. Furthermore, using potting soil containing mediating microorganisms for the potted plants provided to residents can promote the establishment and growth of the tree saplings after they are transplanted into the artificial green space.

[0063] Next, a second embodiment of the present invention will be described. In the second embodiment, as an artificial green space, a street tree belt is constructed between the roadway and the sidewalk in conjunction with the construction of a new road, planting dogwood and azaleas. In the second embodiment, soil and plant roots from the existing grove of trees on site before the construction of the new road are collected and subjected to environmental DNA analysis. Subsequently, soil from the area where street trees are planned to be planted along the newly constructed road is collected and subjected to environmental DNA analysis.

[0064] Environmental DNA analysis identifies filamentous fungus B, an endomycorrhizal fungus present in the sample subjected to environmental DNA analysis, as a support organism capable of establishing a symbiotic network with both dogwood and azalea. In the second embodiment, potting soil containing filamentous fungus B is placed around the root zones of the dogwood and azalea to be planted, and the dogwood and azalea seedlings are then planted.

[0065] According to this embodiment, when planted dogwood and azaleas extend their roots, they can establish a symbiotic relationship with filamentous fungus B contained in the growing medium, thereby receiving nutrients and water from filamentous fungus B. This reduces the stress associated with planting, promotes growth, and reduces the risk of damage such as wilting.

[0066] As described above, the present invention reduces the risk of damage to tall trees that make up artificial green spaces and reduces the costs of forming and maintaining artificial green spaces.

[0067] Next, a third embodiment of the present invention will be described. In the third embodiment, a modified site of approximately 300m x 300m shown in Figure 4 will be used as an example to describe the implementation of a method for artificially constructing an ecosystem.

[0068] The proposed redevelopment area includes a residential plot of approximately 1,000 square meters (around the area labeled "House" in Figure 4), farmland surrounding this plot, and neglected forests (bamboo groves, mixed forests, and cedar forests) behind the farmland. On the opposite side of the road from the residential plot is a flat rice paddy area.

[0069] The cedar forests facing each other across the stream are terraced, and these cedar forests (hereinafter referred to as "terraced forests"), along with the residential areas, farmland, and the terrain along the valley stream, are flat, while the other forests (bamboo groves, mixed forests, and cedar forests facing the road) are slopes. In this embodiment, the bamboo groves, mixed forests, cedar forests (including terraced forests), and the flat land along the valley stream (totaling approximately 60,000 square meters) shown in Figure 4 will be used as the area for modification study.

[0070] First, the attributes of the area under consideration for modification are identified in terms of location and topography. Specifically, regarding the location, the climate zone classification and potential natural vegetation are identified, and then, based on the distance from residential and agricultural land (referred to as "populated areas"), the area is classified into one of the following categories: "adjacent to populated areas" within a straight line distance of 30m from the outer edge of populated areas, "proximity to populated areas" within 50m, "buffer zones" within 70m, or "natural areas" further than 70m.

[0071] The area under consideration for modification in this embodiment is located in the mountainous northern part of Oita Prefecture. The potential natural vegetation consists of Castanopsis sieboldii-Ardisia japonica communities, Castanopsis cuspidata-Ilex crenata communities, and Quercus gilva communities, and is divided into areas adjacent to human settlements, areas near human settlements, buffer zones, and natural areas depending on the location. Of this area under consideration for modification, the areas adjacent to human settlements and areas near human settlements are designated as areas for modification, and the topographic attributes of these areas are identified. Regarding the topography, areas with a slope of less than 8 degrees are classified as flat land, and areas with a slope of 8 degrees or more are classified as slopes. Slopes are further divided into gentle slopes with a slope of less than 20 degrees, steep slopes with a slope of 20 degrees or more and extremely steep slopes with a slope of 35 degrees or more. In the area for modification in this embodiment, the terraced rice paddy forests and areas along the valleys are flat land, while the other forests are mostly gentle slopes with some steep slopes.

[0072] The existing ecosystems in this planned modification area consist of forest ecosystems and herbaceous ecosystems. The area is largely neglected, and when combined with classifications based on vegetation, it is classified into neglected bamboo forests, neglected mixed forests, neglected cedar forests, and semi-managed herbaceous ecosystems (Miscanthus sinensis - Goldenrod - Mallotus japonicus herbaceous community).

[0073] In this embodiment, the existing ecosystem's material supply function, carbon dioxide absorption and sequestration function, and natural disaster protection function are quantified and valued. Since the existing ecosystem is not used for the production of agricultural and forestry products, if the current state is maintained, the value based on its material supply function over the next 30 years is calculated to be zero. Furthermore, since the neglected cedar forest has trees over 50 years old, if the existing ecosystem is left as it is, the value based on its carbon dioxide absorption and sequestration function over the next 30 years is calculated to be zero or negative.

[0074] Furthermore, if the current situation is maintained for the next 30 years, the neglected bamboo forests will expand, reducing their root systems and increasing the risk of overplanted cedar trees collapsing. As a result, their value based on their function in protecting against natural disasters will become zero or even negative.

[0075] Therefore, it was decided to modify approximately 1,200 square meters of land adjacent to human settlements, approximately 5,000 square meters of flat land along the terraced rice fields and stream, and approximately 800 square meters of land close to human settlements within the planned modification area. In particular, the combined area of ​​land adjacent to human settlements, terraced rice fields, and flat land along the stream, totaling approximately 6,200 square meters, was designated for artificial use as a solar power generation site.

[0076] We decided to install a solar power generation system with a system capacity of 380 kW. The value obtained from this power generation (value outside of ecosystem use) would be 3.8 million yen per year if the electricity were sold at 10 yen / kWh.

[0077] In the approximately 7,000 square meter plot of land mentioned above, the existing ecosystem was cleared, and the resulting bare soil was to be treated with plant residues generated by the clearing of the existing ecosystem as a carbon source. Furthermore, for five years after the modification, plant residues generated from nearby farmland were buried or laid on the modified site to enhance soil formation function. The soil formation function for the five years after the modification was valued as the productivity of producing agricultural materials (compost) from the introduced plant residues. In this embodiment, it was calculated that approximately 3,000 kg of agricultural materials (compost) would be produced annually from the approximately 7,000 square meter modified site, with a value of approximately 300,000 yen per year.

[0078] After five years have passed since the modification, 20% of the modified area will be used to produce agricultural materials (compost), while the remaining areas will be used to create an agricultural ecosystem that produces agricultural and forestry products. If the agricultural ecosystem is primarily used to cultivate Aspidistra elatior, the artificial ecosystem in the modified area after five years will produce approximately 60,000 yen worth of agricultural materials and approximately 960,000 yen worth of agricultural products (Aspidistra elatior) annually, and the value of its material supply function is calculated to be approximately 1 million yen per year.

[0079] The power generation project at the planned site will be carried out for 20 years after the modification. After 20 years, the site will be used to construct either an agricultural ecosystem or a managed woodland ecosystem for mushroom cultivation and mushroom cultivation wood production. The value of a 5,000 square meter flat area based on its supply function when constructing an agricultural ecosystem at the planned site was calculated to be approximately 1 million yen per year. The value of a managed woodland ecosystem based on its supply function was calculated to be approximately 300,000 yen per year.

[0080] Furthermore, assuming that at least 4,500 kg of organic matter is introduced annually for 30 years after the modification, the future ecosystem's carbon dioxide absorption and fixation capacity is calculated to be at least 600 kg CO2 per year. Alternatively, other carbon sources, such as carbonized materials (bamboo charcoal or other types of charcoal), may be introduced in place of plant residues in the modified area. Carbonized materials are porous carbon sources, and their introduction can enhance ecosystem functions by increasing carbon dioxide absorption and fixation, providing habitats for soil organisms, and improving water retention.

[0081] As shown above, the value of maintaining the existing ecosystem in its current state for the next 30 years is zero or negative. On the other hand, by temporarily eliminating the existing ecosystem and using the area as a solar power generation site while constructing multiple ecosystems of a different type from the existing ecosystem (future ecosystems), the value obtained from the future ecosystems is estimated to exceed 20 million yen based solely on the value derived from the supply function of materials after 30 years of modification. It was also confirmed that the value derived from soil formation function and carbon dioxide absorption and fixation function will exceed that of the existing ecosystem over the next 30 years.

[0082] Furthermore, by using the modified site for artificial purposes such as solar power generation (not utilizing the ecosystem, but rather using it in a way that does not utilize the ecosystem), it was estimated that the value of the site outside of ecosystem use for 20 years after the modification would be 76 million yen.

[0083] In this embodiment, in order to promote ecosystem development (vegetation growth) in the site to be modified after the end of solar power generation, the physicochemical and biological properties of the soil will be improved. Specifically, as mentioned above, carbon sources such as organic matter (plant residues) will be introduced into the soil of the site to be modified after the modification, and microorganisms that will contribute to the construction of the future ecosystem will be introduced.

[0084] More specifically, soil samples are collected before modification, and soil microbiome analysis is performed. Microorganisms contained in the sample are then isolated and strained using common microbial culture media (such as PDA medium). Organic matter content measurement and soil microbiome analysis can be performed using common methods such as the ignition loss method or environmental DNA analysis.

[0085] Using microbiome analysis, microorganisms beneficial for the construction of future ecosystems (for example, beneficial for cultivating Aspidistra elatior) are identified from among the microorganisms isolated and strained from the sample. Then, the cultures of these strained microorganisms are introduced into the planned modification site by incorporating them into organic matter (for example, pruned branches or plants to be planted). This method of promoting ecosystem construction using microorganisms is similar to that of the first embodiment.

[0086] As described above, according to the present invention, ecosystems whose ecosystem service evaluation values ​​have declined can be modified and used for artificial purposes that generate immediate economic value, while simultaneously creating soil that is beneficial for constructing an ecosystem different from the existing one after such artificial use has ended. In this way, according to the present invention, it is possible to use the planned modification site in a manner that matches the social needs at the time of modification, while creating value 20, 30, or even 50 years later, thus achieving both economic viability and environmental conservation, and balancing the securing of short-term profits with the construction of long-term assets.

[0087] In other words, according to the present invention, when modifying an ecosystem, it is possible to utilize the ecosystem in a way that matches the social needs at that time, while simultaneously building an ecosystem foundation that will respond to changes in social conditions 20 to 30 years from now and meet the needs of the future 20 to 30 years from now.

[0088] Next, a fourth embodiment of the present invention will be described. In the fourth embodiment, two opposing forest slopes in the eastern region of Hokkaido, each approximately 300m wide and 150m high, and a flat area (approximately 300m square) located between these slopes, formed by the filling of a valley with collapsed soil and other debris, are used as disturbed areas for artificially constructing an ecosystem. The forest slopes have lost their vegetation due to landslides, and the flat area has accumulated buried soil, resulting in both areas becoming bare ground.

[0089] Although this disturbed area is bare ground, a natural ecosystem retaining its pre-disaster vegetation exists in the vicinity (within 5 km) of the disturbed area. Vegetation surveys of the natural ecosystems in the disturbed area and its vicinity, along with soil microbial (filamentous fungi) analysis, confirmed that pine seedlings in the disturbed area and its vicinity are in symbiosis with mycorrhizal fungi. Furthermore, environmental DNA analysis confirmed that the soil microbial community in the disturbed area and its vicinity contains not only mycorrhizal fungi but also disease-causing fungi and non-mycorrhizal filamentous fungi beneficial to the growth of pine trees. Some of the non-mycorrhizal filamentous fungi could be isolated and cultured without symbiosis with plants using common microbial culture media such as PDA medium or oatmeal medium.

[0090] The disturbed slopes were to be regenerated as forest land primarily composed of larch trees, which had been planted in the disturbed area before the disaster. Larch trees were designated as both planted trees and lead plants, and mycorrhizal fungi, which coexist with larch trees and aid their growth, were selected as mediating microorganisms (the first mediating microorganism). Then, in the bare areas of the disturbed slopes where it was judged that natural vegetation recovery would be difficult (approximately 50m square in the central part of the slope), soil blocks (approximately 20cm wide x 10cm high, approximately 15cm thick) excavated from nearby land were scattered at intervals of approximately 5m. These soil blocks are natural soil blocks containing pine seedlings, which serve as lead plants and coexist with mycorrhizal fungi, the first mediating microorganism.

[0091] Several years (1-5 years) after placing soil blocks on the disturbed land (slope), non-mycorrhizal filamentous fungi (endophytes) isolated and cultured from the disturbed land or its vicinity are used as a second mediating microorganism. Larch seedlings grown by rooting in a growing medium containing these fungi are then introduced as planted trees. It is preferable to use container seedlings that have been rooted in a container filled with a growing medium containing the second mediating microorganism as planted trees.

[0092] In this embodiment, herbaceous green manure plants (pumpkins) are introduced as lead plants on the disturbed ground. The pumpkins coexist with nitrogen-fixing bacteria as the first mediating microorganisms. Pumpkin cultivation is carried out for at least one cycle, preferably two to three cycles, to allow for symbiosis with nitrogen-fixing bacteria and to observe their growth. Based on the growth status of the pumpkins, the disturbed ground is divided into areas for general crop cultivation (agricultural land), areas for nurseries to cultivate larch seedlings, and areas for other extensive agriculture and forestry, by identifying locations for burying drainage facilities. In the areas designated as nurseries and areas for extensive agriculture and forestry, after the pumpkin cultivation as lead plants is completed, planted trees are cultivated in which a second mediating microorganism has been artificially introduced into symbiosis.

[0093] Furthermore, tree-based green manure plants (such as autumn olive) will be introduced to slopes and areas where extensive agriculture and forestry are practiced. In slopes where larch seedlings included in soil blocks are introduced as lead plants, and larch seedlings are introduced as planting trees after the soil blocks are placed, two types of planting trees will be introduced: larch as the first planting tree and autumn olive as the second planting tree. The order in which autumn olive and larch seedlings are introduced as planting trees does not matter as long as the lead plants are introduced first. Alternatively, autumn olive may be introduced on slopes where larch is not introduced as a lead plant, and then another tree that is commercially viable but prefers fertile soil (such as a fruit tree like a blueberry) may be introduced as planting tree. In this case, nitrogen-fixing bacteria should be introduced in symbiosis with the autumn olive as the first mediating microorganism, and a second mediating microorganism should be selected from indigenous non-mycorrhizal filamentous fungi and introduced in symbiosis with the planting trees.

[0094] In this embodiment, seedlings of planted trees are grown on a surface in which pumpkins are introduced as lead plants, using a growing medium in which a second mediating microorganism has been cultivated. The second mediating microorganism is a non-mycorrhizal filamentous fungus that can establish a friendly symbiotic relationship with both the planted trees and the lead plants, and is easy to isolate, cultivate, and culture. It is particularly preferable to use an indigenous non-mycorrhizal filamentous fungus that constitutes the soil microbial community of disturbed land or its vicinity. Among non-mycorrhizal filamentous fungi, it is especially preferable to use filamentous fungi that are particularly friendly to a variety of plants, such as Trichoderma or Morteria species.

[0095] When selecting indigenous non-mycorrhizal filamentous fungi as the second mediating microorganism, it is preferable to conduct microbiological experiments on the isolated indigenous non-mycorrhizal filamentous fungi. Specifically, it is advisable to test whether beneficial effects are observed, such as promoting germination, rooting, and growth, or exhibiting antagonistic effects against pathogenic fungi, when a culture of the non-mycorrhizal filamentous fungi is placed in the rhizosphere of planted trees to artificially induce symbiosis. Furthermore, it is advisable to experimentally confirm whether introducing the fungi into the rhizosphere of reed plants that are in symbiosis with the first mediating microorganism does not adversely affect the growth of the reed plants.

[0096] In this embodiment, a filamentous fungus of the genus Morteria, isolated from soil near disturbed land and shown to have a broad-spectrum plant growth-promoting effect through analysis and inoculation tests, is used as the second mediating microorganism. The second mediating microorganism is artificially introduced into the symbiosis of larch seedlings, and cuttings or seedlings are grown using a growing medium containing the second mediating microorganism to induce rooting and germination. These larch container seedlings, artificially introduced into symbiosis with the second mediating microorganism, are grown on a disturbed land surface and then introduced to a slope as planted trees.

[0097] This seedling cultivation process artificially introduces a second type of mediating microorganism into the disturbed land. Specifically, pumpkins are introduced as lead plants and nitrogen-fixing bacteria as the first type of mediating microorganism into the disturbed land, and then the second type of mediating microorganism is artificially introduced during seedling cultivation. This second type of mediating microorganism is indigenous and a non-mycorrhizal filamentous fungus that is friendly to a wide range of plants, and therefore can contribute to improving the biological properties of the nursery soil. For this reason, when a nursery is converted into farmland for cultivating crops, it is expected that the second type of mediating microorganism will coexist with the cultivated crops and promote their growth, thus enabling farmland regeneration with reduced burden on "soil preparation."

[0098] Furthermore, on the slopes of disturbed areas, a first mediating microorganism (mycorrhizal fungi) is introduced by arranging soil blocks containing lead plants (larch), and then larch seedlings with a second mediating microorganism (non-mycorrhizal filamentous fungi) artificially coexisting with them are introduced as planting trees. As the second mediating microorganism, a microorganism that can coexist symbiotically with both the lead plants and the planting trees is selected, so that the lead plants introduced before the planting trees support the establishment and growth of the planting trees. By using plants that can grow easily even in harsher environments than the planting trees (thin soil, extreme dryness and wetness, low nutrient and water content, difficulty in absorption, etc.) and that grow quickly (e.g., herbaceous plants and green manure plants), it is possible to restore vegetation to the barren disturbed area quickly with a small amount of planting (i.e., low cost), and to create a base for growing trees that are more difficult to establish than lead plants. Therefore, according to this embodiment, it is possible to achieve faster vegetation recovery compared to leaving the disaster area unattended while reducing the cost of vegetation recovery.

Claims

1. A lead plant capable of coexisting with the first mediating microorganism is introduced into a disturbed area, and the first mediating microorganism is allowed to coexist with the lead plant in its rhizosphere. A method for artificially constructing an ecosystem, comprising introducing the aforementioned lead plants into the disturbed area, and then introducing planting trees, which are trees intended for planting in the disturbed area, The first mediating microorganism is a mediating microorganism that can establish a friendly symbiotic relationship with the planted trees, The lead plant is at least one plant selected from the group consisting of plants of the same species as the planted trees, green manure plants that live in symbiosis with nitrogen-fixing bacteria, mycorrhizal symbiotic trees that live in symbiosis with mycorrhizal fungi, and artificially symbiotic trees in which non-mycorrhizal filamentous fungi are artificially coexisted. A method for artificially constructing an ecosystem, comprising introducing the planted trees into a disturbed area while a second mediating microorganism, a non-mycorrhizal filamentous fungus capable of establishing a friendly symbiotic relationship with the aforementioned reed plants, is in symbiosis with the planted trees in the rhizosphere of the planted trees.

2. The method for artificially constructing an ecosystem according to claim 1, wherein the first mediating microorganism is a filamentous fungus included in the soil microbial flora of either the disturbed area or its vicinity, or both.

3. The method for artificially constructing an ecosystem according to claim 1 or 2, wherein the second mediating microorganism is a filamentous fungus included in the soil microbial flora of either the disturbed area or its vicinity, or both.

4. The method for artificially constructing an ecosystem according to Claim 1, wherein the lead plants are introduced into the disturbed area by scattering a plurality of lead plant blocks, each containing the first mediating microorganism and the lead plants, in the disturbed area.

5. The lead plant is a mycorrhizal fungal symbiotic tree that establishes a symbiotic relationship with the mycorrhizal fungus as the first mediating microorganism, The method for artificially constructing an ecosystem according to claim 4, wherein the lead plant block is a natural soil block in which the lead plant has established a symbiotic relationship with mycorrhizal fungi, or an artificial plant block in which the symbiotic relationship between the lead plant and mycorrhizal fungi has been artificially constructed.

6. The second mediating microorganism is an indigenous nonmycorrhizal filamentous fungus that is included in the soil microbial community of either the disturbed area or its vicinity, and which establishes a symbiotic relationship with plants through hyphae without forming mycorrhizae, A method for artificially constructing an ecosystem according to claim 1 or 2, wherein the planted trees, grown in a growing medium containing a culture of the second mediating microorganism, are introduced into the disturbed area.

7. A reed plant capable of coexisting with the first mediating microorganism is introduced into a disturbed area, and the first mediating microorganism is allowed to coexist with the reed plant in the rhizosphere. A method for artificially constructing an ecosystem, comprising introducing the aforementioned lead plants into the disturbed area, and then introducing planting trees, which are trees intended for planting in the disturbed area, The first mediating microorganism is a mediating microorganism that can establish a friendly symbiotic relationship with the planted trees, The aforementioned lead plant is an artificially created symbiotic tree in which non-mycorrhizal filamentous fungi are artificially introduced, representing an artificial method of constructing an ecosystem.

8. The method for artificially constructing an ecosystem according to claim 1 or claim 7, wherein the planted trees are either potential vegetation species that constitute the potential natural vegetation of the area where the disturbed area is located, or indigenous tree species selected from conventional tree species that grew in or near the disturbed area before the disturbance of the disturbed area.

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