Method for quickly recovering degraded wetland by using micro-topography assembly

Abstract

The application discloses a method for quickly recovering degraded wetlands by micro-landform assembly near nature, and belongs to the technical field of wetland ecological engineering. The application aims to solve the problems of habitat heterogeneity loss and low sustainability of wetland recovery. The method comprises the following steps: 1, selecting a recovery site and evaluating habitat quality; 2, optimizing the base form of the recovery wetland and building a diffuse water network; 3, collecting grass hillocks and micro-landform assembly; 4, segmenting hydrological regulation and dynamic management; 5, evaluating the recovery effect and mediating control. The method has clear principles and strong operability, can strengthen habitat heterogeneity through micro-landform assembly to promote plant diversity, and the design idea is consistent with the near-nature recovery concept, without any engineering implementation risks and secondary ecological risks. The application is applied to the near-nature recovery of degraded wetlands with habitat heterogeneity loss.

Description

Technical Field

[0001] The present invention belongs to the technical field of wetland ecological engineering, and in particular relates to a method for rapidly restoring degraded wetlands by utilizing micro-landform combinations in a near-natural manner. Background Art

[0002] Wetlands, geographical complexes formed by the interaction of aquatic and terrestrial ecosystems, are unique and irreplaceable natural ecosystems on Earth's surface and a vital component of Earth's natural ecological space. They provide multiple ecological and social services, including water conservation, water purification, flood control, and biodiversity maintenance. They play a vital role in maintaining the integrity of Earth's biological structure and optimizing local ecological environments. Habitat heterogeneity is essential for the maintenance and functioning of wetland ecosystems. However, due to the combined effects of climate change and human interference, wetland degradation caused by a lack of habitat heterogeneity is rapidly spreading globally. Therefore, how to achieve near-natural rapid restoration of degraded wetlands by effectively restoring habitat heterogeneity has become a key scientific issue that urgently needs to be addressed in the field of wetland ecological conservation.

[0003] Current approaches to improving the heterogeneity of degraded wetland habitats primarily include mechanical excavation and artificial water replenishment. Mechanical excavation technology has clear principles and is highly operational, enabling short-term landform restoration and improved surface roughness. However, this method severely damages the local environment and is costly. Furthermore, implementing wetland ecological restoration solely from the perspective of landform restoration fails to achieve systematic, coordinated restoration of multiple factors. Artificial water replenishment, while leveraging the wetland's native landforms to create diverse hydrological environments, fostering vegetation-friendly habitats and promoting wetland restoration, relies on point-based water replenishment, which can easily lead to localized soil erosion and carries the risk of localized drought or flooding due to improper water replenishment. Consequently, the restored wetlands lack self-sustaining capacity. Therefore, how to effectively integrate landform restoration with hydrological replenishment to achieve rapid, multi-factor, coordinated, near-natural restoration of degraded wetlands has become a critical scientific issue urgently needed in the field of wetland ecological protection. Summary of the Invention

[0004] The present invention aims to solve the limiting problems of lack of habitat heterogeneity in degraded wetlands and low sustainability after wetland restoration, and provides a method for rapidly restoring degraded wetlands by utilizing micro-topography combinations in a near-natural manner.

[0005] The method of the present invention has a clear principle and strong operability. It can enhance habitat heterogeneity through micro-topography combination to promote the improvement of plant diversity. The design concept is consistent with the concept of near-natural restoration, and there are no hidden dangers in engineering implementation and secondary ecological risks. The method of the present invention was applied to carry out near-natural restoration of degraded wetlands. The plant community coverage and biomass increased by 466% and 746.77% year-on-year respectively. The probability of successful expansion of plant communities can reach 85%, and the probability of sustainable development of wetland ecosystems can reach 100%. The present invention is used for near-natural restoration of degraded wetlands lacking habitat heterogeneity.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] The purpose of the present invention is to provide a method for rapidly restoring degraded wetlands by utilizing micro-topography combinations in a near-natural manner; the method comprises the following steps:

[0008] 1. Select a site for wetland restoration and assess the habitat quality of the selected site: Select degraded wetlands located in river floodplains as target restoration areas, assess the habitat quality of the degraded wetlands, and investigate the surface plant community structure;

[0009] 2. Optimize the base morphology of the restored wetlands after evaluation and create a flooded water network;

[0010] 3. Then, the grass mound body is collected and the micro-topography is assembled;

[0011] Fourth, carry out segmented hydrological regulation and dynamic management;

[0012] 5. Then, the restoration effect evaluation and mediation control will be carried out: the restoration effect evaluation work will be carried out in August of the restoration year and the following year, and auxiliary seed input and short-term water replenishment measures will be carried out in the following year.

[0013] It is further defined that in step one, the target restoration area for wetland restoration is delineated in the swamp behind the floodplain or the detour fan area; wherein the delineated target restoration area is 30-50 meters away from the main river channel in a straight line and has a relative elevation of less than 2 meters, and there is no livestock grazing and industrial and agricultural wastewater discharge in the upper reaches of the adjacent river.

[0014] Furthermore, in step 1, habitat quality assessment is to define the soil organic matter content, the degree of habitat heterogeneity loss, the degree of vegetation degradation, and the degree of germplasm loss in the region;

[0015] It is further specified that the soil organic matter content in the site selection area is greater than 25g / kg, the pH value is less than 6.9, and the salinity is less than 0.3% as the standards for site selection soil.

[0016] Furthermore, the criteria for lack of habitat heterogeneity are defined as surface roughness less than 0.2 and slope change rate less than 0.5‰.

[0017] Further definition, the definition of vegetation degradation is that the number of surface plant community species is less than 3, the vegetation coverage is less than 20%, the proportion of annual plants is greater than 60%, and the biomass is less than 150g / square meter.

[0018] Furthermore, the species richness of the soil seed bank is less than 5 species and the density is less than 50 plants / square meter as the criteria for defining germplasm loss.

[0019] It is further defined that in step two, the restoration of the wetland base morphology is optimized in early to mid-April, and the secondary restoration unit is delineated with a specification of 10 meters × 10 meters in the target restoration area. A micro-plowing machine is used to rotary till the surface soil of 0-40 cm depth in the secondary restoration unit, and after the rotary tillage is completed, the soil in the secondary restoration unit is manually leveled to a terrain slope of less than 2°.

[0020] It is further defined that in step 2, the construction of the overflow water network is to use micro-channel machinery to dig interconnected ecological ditches with a depth of 20 cm and a width of 60 cm near and away from the edge of the river channel of each secondary restoration unit; the soil generated by the excavation of the interconnected ecological ditches is required to be piled up with ecological separation dams with a height of 20 cm and a width of 60 cm at the secondary restoration unit perpendicular to the edge of the river channel and away from the edge of the river channel, thereby forming a one-way strip-shaped radial water overflow network.

[0021] It is further defined that in step three, the grass mounds are collected in late April, and the above-ground parts of the grass mounds or the roots of the mound-like plants are collected at a collection interval of 10 meters in the adjacent natural wetland, with a collection density of less than 5 mounds / square meter. The initial development level of sedge grass mounds is defined as a base diameter of less than 20 cm and a height of less than 30 cm, the medium development level of sedge grass mounds is defined as a base diameter of 20-35 cm and a height of 30-40 cm, and the mature development level of sedge grass mounds is defined as a base diameter greater than 35 cm and a height greater than 40 cm. A 2.5m x 2.5m area is temporarily designated as a third-level restoration unit within the second-level restoration unit, and 4 mounds of initial development level sedge grass mounds, 4 mounds of medium development level sedge grass mounds, and 2 mounds of mature development level sedge grass mounds are cultivated at a depth of 10 cm.

[0022] It is further defined that in step three, the micro-topography is: every 5 sedge grass mounds are arranged in a five-star shape, among which two sedge grass mounds with medium development are set near the water direction, two sedge grass mounds with initial development are set at the secondary adjacent position, and one mature development grass mound is set at the far end. The distance between each adjacent mound is 20-30 cm.

[0023] By improving the trapping efficiency of germplasm resources through micro-topography configuration, efficient germplasm resource trapping can be realized to achieve species source self-supply, efficient enrichment and retention of plant seeds and spores are realized through terrain regulation, a self-sustaining species source supply system is established to drive the near-natural restoration of the ecological system; a multi-dimensional habitat synergy is constructed: coupling hydrological dynamics, three types of heterogeneous habitat units of arid, humid and flooded are simultaneously formed in a single system to meet the collaborative planting and development needs of xerophytes, hygrophytes and hydrophytes.

[0024] Further limited, in step four, the segmented hydrological regulation is to artificially introduce natural river water to the target restoration area adjacent to the river side of the connecting ecological ditch in early May, and then to supplement water to the surface in a flooding form to a depth of 15-20 cm, combined with the grassy mound to create a suitable habitat for hydrophytes, hygrophytes and xerophytes.

[0025] Further limited, in step four, the dynamic management is to use river pulse water to supply the target restoration area during the wet period to supplement and trap water-borne germplasm resources. In late October, the second artificial water supply is implemented to a surface flooding depth of 20 cm. The surface water level and moisture content at the edge of the adjacent and distant river are monitored every 10 days from early May to early October, and the soil moisture content is less than 60% as the defined standard to artificially mediate water supply to the initial hydrological conditions.

[0026] Further limited, in step five, the restoration effect evaluation and mediation and control are to collect 20-30% of the total mature seeds produced in the target restoration area in August of the repair year, and then store them in a sand at -24℃ / 4℃ variable temperature environment until April of the next year. In May of the next year, the seeds are randomly sown in the micro-topography configuration area at a density of 200-300 per square meter. In late October of the next year, artificial water supply is implemented to a surface flooding depth of 20 cm. The restoration effect evaluation is continuously carried out in August of the repair year, the first year and the second year. In the repair year, the restoration defined standard is that the number of surface plant community species is greater than 12 and includes hydrophytes and hygrophytes, the vegetation coverage is greater than 60%, and the biomass is greater than 550g / square meter. In the first year of repair, the restoration defined standard is that the number of plant community species is greater than 16 and includes hydrophytes, hygrophytes and xerophytes, the vegetation coverage is greater than 75%, and the biomass is greater than 800g / square meter. In the second year of repair, the restoration defined standard is that the number of surface plant community species is greater than 20 and includes hydrophytes, hygrophytes and xerophytes, the vegetation coverage is greater than 80%, and the biomass is greater than 1000g / square meter. The ecological partition dam is removed after the target restoration area continuously reaches the restoration evaluation standard.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] 1. The principle of the present invention is clear, easy to implement and low-cost. The content of the method of the present invention is in line with the concept of nature-based solution. By setting up an interconnected overflow water network, it can achieve full-area replenishment of the target restoration area and effectively avoid the risks of soil erosion and local landform erosion caused by point-type water body impacts and flood pulses. After the implementation of the method of the present invention, the wetland hydrological process covering the entire life cycle of plants can be reconstructed in the same year, thereby activating dormant germplasm resources by creating a suitable hydrological habitat, and no frequent manual maintenance is required. It is suitable for wide promotion and application in the restoration of degraded wetlands with lack of habitat heterogeneity caused by the dislocation of water resources in time and space.

[0029] 2. The present invention can effectively enhance the level of heterogeneity in degraded wetland habitats. The method of the present invention deploys sedge grass mounds or mound-like plant root systems in initial development, intermediate development, and mature states in the secondary restoration area, which can jointly enhance the level of habitat heterogeneity with the created hydrological environment, and jointly create multiple hydrological habitats that take into account the growth and development of aquatic, wetland, and xerophytic plants. At the same time, the micro-topography created by sedge grass mounds of different development levels can change the amount and spatial distribution of solar radiation reaching the soil surface, and constitute the heterogeneity of surface organic matter, nutrient availability, and redox conditions, thereby forming a nutrient resource redistribution pattern, promoting plant community development, and enhancing community stability.

[0030] 3. The present invention can effectively improve the efficiency of intercepting germplasm resources. The method of the present invention arranges sedge grass mounds or mound-shaped plant roots in a five-star shape within the three-level restoration unit, and sets two sedge grass mounds of medium development in the vicinity of the incoming water, two sedge grass mounds of initial development in the secondary vicinity, and one mature development mound at the far end. This design can effectively slow down the flow rate of the water body, promote the deposition and interception of water-borne germplasm resources, thereby achieving efficient capture of germplasm resources and near-natural rapid colonization of vegetation. In addition, the present invention can increase the surface roughness to 0.27 and the slope change rate to 0.78‰ through the above-mentioned multi-development stage grass mound combination and divergent arrangement, which can reduce the scouring intensity of surface runoff. At the same time, a local sedimentation area is formed through the stepped distribution of grass mounds, thereby achieving the common sedimentation of seeds and sediment, creating a stable germination microhabitat for the germination of germplasm resources.

[0031] 4. The method of the present invention is safe and effective, and does not pose any ecological safety risks. The water body used in the present invention is a natural river water body, and it clearly avoids livestock interference and industrial and agricultural pollution in the upper reaches of the river. At the same time, the construction process of the target restoration area does not involve environmental pollution behaviors such as fertilizer application and pesticide application, and there is no risk of eutrophication and point source pollution. At the same time, the matrix resources used in the micro-topography construction process of the present invention are all collected intermittently at a low density over a long distance in the adjacent natural wetlands, and there is no risk of any native wetland destruction or invasion of alien species.

[0032] In order to further understand the features and technical contents of the present invention, please refer to the following detailed description of the present invention and the accompanying drawings. However, the accompanying drawings are provided for reference and illustration only and are not intended to limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of the target recovery area structure;

[0034] Figure 2 Surface roughness change results;

[0035] Figure 3 Slope change rate results;

[0036] Figure 4 Results of changes in the number of surface plant species;

[0037] Figure 5 Results of changes in surface plant community coverage;

[0038] Figure 6 Biomass change results;

[0039] Figure 1 In the middle, 1 is adjacent to the main river channel; 2 is the water pipeline; 3 is the solar pump; 4 is the interconnected ecological ditch; 5 is the secondary restoration unit; 6 is the medium-developed sedge grass mound; 7 is the initial-developed sedge grass mound; 8 is the mature-developed sedge grass mound; 9 is the ecological dividing dam; 10 is the tertiary restoration unit demarcation line (temporary);

[0040] Different lowercase letters represent that the differences in surface roughness, slope change rate, number of surface plant species, coverage, and biomass within the target restoration area between different restoration years reach a significant level at the 0.05 hypothesis level; among them, a is significantly different from b, c, and d, b is significantly different from a, c, and d, c is significantly different from a, b, ab, and d, d is significantly different from a, b, ab, and c; and ab is significantly different from c and d. DETAILED DESCRIPTION

[0041] The method of using micro-landform combination to quickly restore degraded wetlands in a near-natural manner is completed in the following steps:

[0042] Step 1: Wetland restoration site selection and habitat quality assessment

[0043] Degraded wetlands located in river floodplains were selected as target restoration areas to assess the habitat quality of the degraded wetlands and investigate the surface plant community structure.

[0044] The selected target recovery area is located in the backswamp or meander fan area to ensure water resource allocation and supply during the recovery stage and self-maintenance process, and to avoid the impact of extreme hydrological events such as floods on the target recovery area; the target recovery area and the adjacent main river channel are required to be within 30-50 meters in straight line distance and less than 2 meters in relative elevation to ensure that the target recovery area can be irradiated by regular water pulses to form a periodic hydrological rhythm process and supply germplasm resources; there is no livestock grazing and industrial and agricultural wastewater discharge in the upstream of the adjacent river to avoid ecological risks such as water body eutrophication and biodiversity loss caused by water pollution in the restored wetland;

[0045] After the initial site selection of the target recovery area is completed, the soil organic matter content, pH, and salinity of the target recovery area are detected, and the soil quality is qualified as the soil organic matter content is greater than 25g / kg, the pH value is less than 6.9, and the salinity is less than 0.3%,

[0046] to avoid soil salinization and secondary hazards that hinder the recovery process of the surface plant community; the habitat heterogeneity loss standard is that the surface roughness is less than 0.2 and the slope change rate is less than 0.5‰; the target recovery area is required to investigate the composition and structure of the surface plant community, the proportion of life forms, and the vegetation coverage is less than 20%, the proportion of annual plants is greater than 60%, and the biomass is less than 150g / square meter as the necessary standard for defining the necessity of vegetation restoration; the target recovery area is required to investigate the species richness and density of the soil seed bank, and the species richness is less than 5 and the density is less than 50 plants / square meter as the germplasm loss definition standard.

[0047] Step two, optimization of the recovery wetland base form and construction of the diffuse water network

[0048] During the early to mid-April period, the soil base environment of the target recovery area is repaired, and a one-way strip radial water diffuse network is set up.

[0049] It is required to delineate secondary restoration units with a specification of 10 meters x 10 meters within the target restoration area for the precise implementation of base morphology transformation and overland flow network construction; it is required to use micro-ploughing machinery to till the surface soil at a depth of 0-40 cm in the secondary restoration unit to improve the soil physical structure and activate the deep soil seed bank, thereby optimizing the soil structure and promoting the rapid reconstruction of native plant communities; it is required to manually level the soil in the secondary restoration unit to a terrain slope of less than 2° after the surface soil is tilled to ensure the continuity of the water overland flow process; it is required to use micro-channel machinery in each secondary restoration unit Interconnected ecological ditches with a depth of 20 cm and a width of 60 cm are dug near and away from the edge of the river to form a flooded water network to achieve multi-stage sheet flow replenishment in the target restoration area; the soil generated by the excavation of the interconnected ecological ditches is required to be piled up in the secondary restoration unit perpendicular to the edge of the river and away from the edge of the river to form an ecological separation dam with a height of 20 cm and a width of 60 cm to ensure that the water body is continuously and directionally transported within each secondary restoration unit by the flooded water network, and the risk of vegetation waterlogging caused by excessive surface flooding can be avoided through lateral overflow during the flood season.

[0050] Step 3: Grass mound collection and micro-topography combination

[0051] In late April, the aboveground parts of sedge grass mounds at multiple developmental stages were collected, and local micro-geomorphological groups were developed based on the development level of the grass mounds.

[0052] It is required to collect the above-ground part of the grass mound or the roots of the mound-like plants at an interval of 10 meters in the adjacent natural wetlands. At the same time, the collection density during the collection process should be less than 5 mounds / square meter to avoid local high-intensity collection causing habitat heterogeneity disturbance and biodiversity loss; it is required to define the initial development level of sedge grass mounds with a base diameter of less than 20 cm and a height of less than 30 cm as the standard, define the medium development level of sedge grass mounds with a base diameter of 20-35 cm and a height of 30-40 cm as the standard, and define the mature development level of sedge grass mounds with a base diameter of more than 35 cm and a height of more than 40 cm as the standard; it is required that during the micro-geomorphological combination process, a 2.5m×2.5m area be temporarily drawn within the secondary restoration unit as a tertiary restoration unit, and each tertiary restoration unit should be a tertiary restoration unit. The restoration unit is equipped with 4 sedge grass mounds with initial development, 4 sedge grass mounds with medium development, and 2 sedge grass mounds with mature development; it is required that every 5 sedge grass mounds in the third-level restoration unit are arranged in a five-star shape, among which two sedge grass mounds with medium development are set near the direction of water inflow, two sedge grass mounds with initial development are set at the secondary adjacent position, and one mature development mound is set at the far end, so as to slow down the flow rate of overflowing water through gradient micro-topography design, thereby promoting the interception and development of water-borne germplasm resources, and at the same time meet the growth and development needs of aquatic, wetland and xerophytic plants through the creation of diversified heterogeneous habitats; it is required to cultivate grass mounds at a depth of 10 cm and the distance between adjacent mounds is 20-30 cm, so as to reserve water flow channels and self-development space for grass mounds.

[0053] Step 4: Segmented hydrological regulation and dynamic management

[0054] In early May, artificial water was diverted to replenish the target restoration area in the form of overflow, and surface water level changes were dynamically monitored during the plant growing season of the restoration year.

[0055] It is required that in early May, after the micro-geomorphology is completed, solar pumps should be used to guide natural river water to the connected ecological ditches on the river side of the target restoration area, so as to form a cascade flow to continuously replenish water to the target restoration area to reduce the risk of soil erosion caused by high-speed water scouring; it is required that the first water replenishment should be to a surface flooding depth of 15-20 cm, so as to combine with the sedge grass dunes to create a suitable habitat for aquatic, wetland and xerophytic plants; it is required to use river pulse water to replenish the target restoration area during the flood season to increase the input of water-borne germplasm resources and use the rough surface of the grass dunes and the micro-geomorphology combination characteristics to intercept germplasm resources to achieve Rapid replenishment of germplasm resources; requiring artificial water diversion and replenishment to a surface flooding depth of 20 cm in late October of the restoration year, so as to avoid low temperature frost damage to plant roots and dormant seeds through winter water reserves, and provide a suitable hydrological environment for the rapid germination of wetland seeds in the spring of the following year after water infiltration; requiring the target restoration area to monitor the surface water level and soil moisture content near and far from the river edge every 10 days from early May to early October of the year of construction, and carry out artificial water replenishment work to the initial hydrological conditions when the soil moisture content is less than 60%, so as to avoid drought-induced imbalance in plant cell metabolism and damage to the membrane system.

[0056] Step 5: Recovery effect evaluation and mediation control

[0057] Restoration effectiveness evaluation work was carried out in the year of restoration and in August of the following year, and auxiliary seed input and short-term water replenishment measures were implemented the following year.

[0058] The restoration is required to meet the following criteria: the number of species in the ground plant community is greater than 12, including aquatic and wetland species, the vegetation coverage is greater than 60%, and the biomass is greater than 550 g / m2 in the first year of restoration; the number of species in the ground plant community is greater than 16, including aquatic, wetland, and dryland species, the vegetation coverage is greater than 75%, and the biomass is greater than 800 g / m2 in the second year of restoration, to ensure the sustainability of the self-maintenance process of the ecosystem in the target restoration area; the total production of mature seeds in the first year of restoration is collected after the evaluation of the restoration effect, and the seeds are stored in a-24℃ / 4℃ variable temperature environment until April of the following year to soften the seed coat and promote the synthesis of gibberellin and cytokinin, thereby breaking seed dormancy and achieving high-efficiency seed germination; the seeds are randomly scattered in the micro-topographic group area at a density of 200-300 seeds / m2 in May of the following year to strengthen the input process of germplasm resources in a near-natural way; artificial water supply is required in late October of the following year to maintain a water depth of 20 cm on the ground to continuously avoid the risk of low-temperature freezing in winter and ensure the suitability of the hydrological environment in the spring of the following year; the restoration status is evaluated after 2 years of construction in the target restoration area, and the rapid restoration criteria are set as follows: the number of species in the ground plant community is greater than 20, including aquatic, wetland, and dryland species, the vegetation coverage is greater than 80%, and the biomass is greater than 1000 g / m2; the ecological separation dam is removed after the rapid restoration criteria are met to achieve connectivity between the target restoration area and the adjacent wetland habitat, thereby realizing the overall transformation of the near-natural restoration of degraded wetlands to self-maintenance development.

[0059] Example 1:

[0060] The Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, undertakes the project of ecological restoration of degraded wetlands and carries out near-natural rapid restoration of habitat damage type degraded wetlands in the Songnen Plain. In the process of near-natural restoration of degraded wetlands, the following methods are followed:

[0061] Step one, selection of restoration wetlands and assessment of habitat quality

[0062] In July 2021, soil quality testing and above-and-underground plant community structure analysis were carried out in a degraded wetland in the meandering fan area of the Nenjiang River floodplain in Jilin Province. The degraded wetland is 45.6 meters away from the main river of the Nenjiang River, with a relative elevation of 1.2 meters. The upstream of the Nenjiang River section where the area is located is a national nature reserve area, and there is no livestock grazing and industrial and agricultural production history. The soil organic matter content of the area is 26.18 g / kg, the pH value is 6.5, and the salinity is 0.15%. The surface roughness of the area is 0.05, and the slope change rate is 0.25‰. There are a total of 2 annual plants on the ground of the area, with a vegetation coverage of 15% and a biomass of 124 g / m2. The soil seed bank germinates 4 annual plants, with a species density of 32 plants / m2, which is a typical degraded wetland.

[0063] Step 2: Restoration of wetland base morphology optimization and construction of overflow water network

[0064] From April 2 to April 10, 2022, five secondary restoration units with a size of 10 meters x 10 meters were delineated within the target restoration area, and each secondary restoration unit was adjacent to and parallel to the other. A micro-ploughing machine was used to till the soil 40 cm deep in the surface of the secondary restoration unit, and then the surface soil was manually leveled until the terrain slope was less than 2°. A micro-channel machine was used to dig interconnected ecological ditches with a depth of 20 cm and a width of 60 cm near and away from the edge of the Nenjiang River in each secondary restoration unit, and the resulting soil was used to build ecological separation dams with a height of 20 cm and a width of 60 cm on the periphery of the ecological ditches in the secondary restoration units perpendicular to the river edge and away from the river edge, that is, away from the edge of the Nenjiang River.

[0065] Step 3: Grass mound collection and micro-topography combination

[0066] From April 16 to April 20, 2022, the aboveground portions of sedge mounds in the initial, intermediate, and mature stages were collected at 10-meter intervals within the natural sedge wetland adjacent to the target restoration area, with a local sampling density of 3 mounds / square meter. Sedge mounds were defined as initial stages with a base diameter less than 20 cm and a height less than 30 cm, intermediate stages with a base diameter of 20-35 cm and a height of 30-40 cm, and mature stages with a base diameter greater than 35 cm and a height greater than 40 cm. Within the secondary restoration unit, a temporary 2.5-meter by 2.5-meter area was designated as a tertiary restoration unit, where four initial stages, four intermediate stages, and two mature stages of sedge were introduced. Every five sedge grass mounds are arranged in a five-star shape. Two sedge grass mounds with medium development are planted near the Nenjiang River. Two sedge grass mounds with initial development and one sedge grass mound with mature development are set up at 25 cm and 50 cm from the far end. Each grass mound is cultivated with a standard burial depth of 10 cm.

[0067] Step 4: Segmented hydrological regulation and dynamic management

[0068] From May 2 to May 8, 2022, solar-powered pumps were installed between the Nenjiang River and the target restoration area to divert water to the interconnected ecological ditches adjacent to the river in the target restoration area. The initial water replenishment was completed after flooding the target restoration area to a depth of 15 cm in the form of overland flow. During the wet season, the Nenjiang River channel was extended to both ends to form a pulsed water body that intermittently replenished the target restoration area. During the plant growing season, from May to October, the surface flooding depth in the target restoration area ranged from 1 to 10 cm. From October 16 to 18, artificial water diversion was implemented again to replenish the surface water to a depth of 20 cm to prevent winter low temperature damage and to preset a suitable hydrological environment for the following spring.

[0069] 5. Recovery Effect Evaluation and Mediation Control

[0070] Procedure: From August 15 to 20, 2022, mature seeds, representing approximately 25% of the total seed production for the year, were collected from the target restoration area and stored in sand in a -24°C / 4°C temperature range until April of the following year to break seed dormancy. From May 10 to 12, 2023, seeds were randomly sown at the micro-geomorphological distribution center at a density of 250-300 seeds per square meter to achieve a near-natural, efficient replenishment of germplasm resources and enhance establishment efficiency. Artificial watering was performed again from October 14 to 16, 2023.

[0071] Restoration effect evaluations will be carried out in August 2022, August 2023 and August 2024 respectively. In the year of restoration, the evaluation criteria will be that the number of surface plant community species is greater than 12 and includes aquatic and wetland species, the vegetation coverage is greater than 60%, and the biomass is greater than 550g / square meter. In the second year of restoration, the evaluation criteria will be that the number of surface plant community species is greater than 16 and includes aquatic, wetland and xerophytic species, the vegetation coverage is greater than 75%, and the biomass is greater than 800g / square meter. Two years after restoration, the evaluation criteria will be that the number of surface plant community species is greater than 20 and includes aquatic and wetland species, the vegetation coverage is greater than 80%, and the biomass is greater than 1000g / square meter.

[0072] An assessment of the surface plant community within the target restoration area in 2022 revealed 13 species, including aquatic and wetland species, with a vegetation coverage of 62% and a biomass of 573g / m2. By 2023, the surface plant community had 17 species, including aquatic, wetland, and xerophytic species, with a vegetation coverage of 78% and a biomass of 850g / m2. By 2024, the surface plant community had 22 species, including aquatic, wetland, and xerophytic species, with a vegetation coverage of 85% and a biomass of 1050g / m2. The surface roughness reached 0.46, and the slope gradient was 0.75‰. Following the completion of the continuous assessment in August 2024, the ecological barrier dam was removed to connect the target restoration area with the adjacent wetland habitat.

Claims

1. A method for rapidly restoring degraded wetlands using micro-landform combinations close to nature, characterized in that: The following steps are involved:

1. Select a site for wetland restoration and assess the habitat quality of the site; 2. Optimize the base morphology of the restored wetlands after evaluation and create a flooded water network; 3. Then, the grass mound body is collected and the micro-topography is assembled; Fourth, carry out segmented hydrological regulation and dynamic management; 5. Then evaluate the recovery effect and conduct mediation and control; The restoration of the wetland base morphology was optimized in early to mid-April. Secondary restoration units were demarcated with a size of 10 meters by 10 meters within the target restoration area. The surface soil of the secondary restoration unit was tilled to a depth of 0-40 cm using a micro-ploughing machine. After the tillage was completed, the soil in the secondary restoration unit was manually leveled to a terrain slope of less than 2°. Grass mounds were collected in late April, with the aboveground parts of the mounds or roots of mound-like plants collected at intervals of 10 meters in adjacent natural wetlands, with a collection density of less than 5 mounds per square meter. Initial development sedge mounds were defined as having a base diameter of less than 20 cm and a height of less than 30 cm, intermediate development sedge mounds as having a base diameter of 20-35 cm and a height of 30-40 cm, and mature development sedge mounds as having a base diameter greater than 35 cm and a height greater than 40 cm. Within the secondary restoration unit, a 2.5 m x 2.5 m area was temporarily designated as a tertiary restoration unit, where four initial development sedge mounds, four intermediate development sedge mounds, and two mature development sedge mounds were planted at a depth of 10 cm. Every five sedge mounds are arranged in a five-star shape, with two sedge mounds of medium development near the water source, two sedge mounds of initial development near the secondary proximity, and one mature development mound at the far end. The distance between adjacent mounds is 20-30 cm. It can effectively slow down the flow rate of water bodies, promote the deposition and interception of waterborne germplasm resources, and thus achieve efficient capture of germplasm resources and near-natural rapid establishment of vegetation; Through the combination and divergent arrangement of grass mounds at multiple developmental stages, the scouring intensity of surface runoff can be reduced. At the same time, local sedimentation areas can be formed through the stepped distribution of grass mounds, so that seeds and sediment can be settled together, creating a stable germination microhabitat for the germination of germplasm resources.

2. The method according to claim 1, characterized in that The target restoration area for wetland restoration is demarcated in the swamp behind the floodplain or the detour fan area. The demarcated area is 30-50 meters away from the main river channel and has a relative elevation of less than 2 meters. There is no livestock grazing and industrial and agricultural wastewater discharge in the upper reaches of the adjacent river.

3. The method according to claim 1, characterized in that Habitat quality assessment is to define the soil organic matter content, the degree of habitat heterogeneity loss, the degree of vegetation degradation, and the degree of germplasm loss in the region; Among them, the soil organic matter content in the selected area is greater than 25g / kg, the pH value is less than 6.9, and the salinity is less than 0.3%; The surface roughness less than 0.2 and the slope change rate less than 0.5‰ were used as the criteria for lack of habitat heterogeneity; The criteria for defining vegetation degradation are that the number of surface plant community species is less than 3, the vegetation cover is less than 20%, the proportion of annual plants is greater than 60%, and the biomass is less than 150g / m2; The criteria for defining germplasm loss are a soil seed bank with a species richness of less than 5 species and a density of less than 50 plants per square meter.

4. The method according to claim 1, characterized in that The construction of the overflow water network is to use micro-channel machinery to dig interconnected ecological ditches with a depth of 20 cm and a width of 60 cm near and away from the edge of the river in each secondary restoration unit; the soil generated by the excavation of the interconnected ecological ditches is required to be piled up in the secondary restoration unit perpendicular to the edge of the river and away from the edge of the river to form an ecological separation dam with a height of 20 cm and a width of 60 cm, thereby forming a one-way strip-shaped radial water overflow network.

5. The method according to claim 1, characterized in that: In the first ten days of May, segmented hydrological regulation artificially introduced natural river water to the interconnected ecological ditch on the river side of the target restoration area, and then replenished water in the form of overflow to a surface flooding depth of 15-20 cm. Combined with grass hills, it creates a suitable habitat for aquatic, wetland and xerophytic plants.

6. The method according to claim 1, characterized in that Dynamic management utilizes pulsed river water to replenish target restoration areas during the flood season to supplement and retain waterborne germplasm resources; implements a second artificial water replenishment in late October until the surface flooding depth reaches 20 cm; monitors the surface water level and moisture content near and away from the river edge every 10 days from early May to early October, and artificially mediates water replenishment to the initial hydrological conditions when the soil moisture content is less than 60%.

7. The method according to claim 1, characterized in that Restoration effect evaluation and mediation control: In August of the restoration year, 20%-30% of the mature seeds of the total production in the target restoration area were collected and stored in sand in a temperature-variable environment of -24℃ / 4℃ until April of the following year; in May of the following year, the seeds were randomly sown at a density of 200-300 seeds / square meter in the micro-geomorphological combination area; in late October of the following year, water was artificially diverted to replenish the surface water to a depth of 20 cm; restoration effect evaluation was carried out continuously in August of the restoration year, the first year, and the second year. In the restoration year, the number of surface plant community species was greater than 12 and included aquatic and wetland species, and the vegetation The restoration criteria are coverage greater than 60% and biomass greater than 550g / square meter. In the first year of restoration, the restoration criteria are plant community species greater than 16 and including aquatic, wetland and xerophytic species, vegetation coverage greater than 75%, and biomass greater than 800g / square meter. In the second year of restoration, the restoration criteria are surface plant community species greater than 20 and including aquatic, wetland and xerophytic species, vegetation coverage greater than 80%, and biomass greater than 1000g / square meter. The ecological separation dam will be removed after the target restoration area continuously meets the restoration assessment criteria.

Images