Lake natural ecological restoration method

Abstract

The present application relates to a kind of lake natural ecological restoration method, historical ecological data analysis and ecological system status survey are carried out to the lake to be repaired;Pioneer plant buffer zone is formed by planting floating leaf plants in the center area of the lake to be repaired and / or wind and wave center area;At least one sub-recovery area is set in the lake to be repaired, and all sub-recovery areas are carried out ecological restoration according to preset order, and the measures of ecological restoration include constructing stable primary submersed plant community in each sub-recovery area;Wherein, the primary submersed plant community can stably produce propagule;The propagule produced by each sub-recovery area can be naturally dispersed and planted and spread to other locations outside the sub-recovery area in the lake to be repaired by natural force, to form stable secondary submersed plant community, to expand the repaired area that has been completed;Propagule further disperses, plants and spreads.The outstanding advantages are less investment, fast repair, and suitable for the repair of medium and large lakes.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, and in particular to a method for natural ecological restoration of lakes. Background Technology

[0002] Natural ecological restoration of lakes is a crucial means of improving lake water quality and restoring ecosystem health. Especially after land-based pollution control measures have achieved certain results, and the marginal benefits of further water quality improvement begin to diminish, the enhancement of lake self-purification capacity primarily depends on the restoration and strengthening of its ecosystem functions. Lake ecological restoration methods mainly involve improving habitat conditions within the lake, then artificially introducing submerged plant propagules and allowing them to grow into plants, or directly planting submerged plants. Based on this, aquatic animals are introduced to cultivate a rich microbial system, thereby forming a complex and stable aquatic ecosystem.

[0003] The restoration of aquatic ecosystems in small lakes mostly relies on engineering measures, such as constructing large-scale enclosures and introducing submerged plants. This approach is costly and results in unstable ecosystems, severely hindering the progress of ecological restoration in large and medium-sized lakes in my country. Meanwhile, lakes with an area of ​​50 km²... 2 There are still few successful cases of ecological restoration of large and medium-sized lakes. The existing artificial ecological restoration methods applied to large lakes have the following main problems: the existing technologies are not sufficiently experienced in large and medium-sized lakes; the restoration area required to achieve system stability is large, the financial investment is large, and the restoration time is long; the artificially constructed system has certain problems with the adaptability and sustainability of each lake, such as its weak ability to resist disturbances such as algae, wind and waves, and fish and birds grazing. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a method for natural ecological restoration of lakes, which solves the technical problem that the lack of effective restoration schemes in the current ecological restoration of large and medium-sized lakes leads to poor restoration effect and high restoration cost.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0008] In a first aspect, embodiments of the present invention provide a method for natural ecological restoration of lakes, comprising the following steps: S1, analyzing historical ecological data and investigating the current state of the ecosystem of the lake to be restored; S2, based on the analysis and investigation results of step S1, planting floating-leaved plants in the central area and / or the center area of ​​wind and waves of the lake to be restored to form a pioneer plant buffer zone; S3, based on the analysis and investigation results of step S1, setting at least one sub-restoration area within the lake to be restored, and carrying out ecological restoration on all sub-restoration areas in a preset order, wherein the ecological restoration measures include constructing a stable primary submerged plant community in each sub-restoration area; wherein the primary submerged plant community... The plant community can stably produce propagules; S4, the propagules produced in each sub-restorement area can naturally spread and establish themselves in other locations outside the sub-restorement area within the lake to be restored with the help of natural forces, forming a stable secondary submerged plant community to expand the completed restoration area; the natural forces include water flow, wind and waves, fish activity and human water activities; S5, the propagules produced by the secondary submerged plant community and the propagules produced by the primary submerged plant community further spread and establish themselves in other locations within the lake to be restored with the help of natural forces, and over time, the coverage area of ​​the submerged plant community reaches a preset proportion of the total area of ​​the lake to be restored.

[0009] As a preferred embodiment of the present invention, in the lake natural ecological restoration method, S1, the historical ecological data analysis includes, but is not limited to, the location of the historical grass-covered area of ​​the lake to be restored, the evolution process of the historical grass-covered area, and the main influencing factors involved in the evolution process; the current status survey of the ecosystem includes, but is not limited to, the current status of the meteorology, hydrology, water quality, substrate, biological group structure, and submerged plant propagule pool of the lake to be restored; through the above analysis and survey, the following information is obtained, including but not limited to: prevailing wind direction, location of the wind and wave center, adaptive floating-leaved plant species growing in the lake to be restored, adaptive submerged plant species that survive in the lake to be restored and can stably produce propagules, regional habitat conditions and ecological background conditions of the lake to be restored, and the location of the historical grass-covered area.

[0010] Specifically, pioneer plant buffer zones are set up based on prevailing wind direction and the location of the wave center; the types of submerged plants used in the restoration process are selected based on the adaptable floating-leaved plant species and adaptable submerged plant species that grow in the lake to be restored; and the distribution locations of sub-restoration areas are set based on the regional habitat conditions, ecological background conditions, and historical grass-covered areas of the lake to be restored.

[0011] As a preferred embodiment of the present invention, in the lake natural ecological restoration method, in S3, based on the analysis of historical ecological data and the current status survey of the ecosystem of the lake to be restored in S1, the distribution locations of sub-restoration areas are set; when the number of sub-restoration areas is ≥2, different sub-restoration areas are ecologically restored in the following preset order: the first sub-restoration area to undergo ecological restoration is the preliminary restoration area, and the remaining sub-restoration areas will begin restoration after the preliminary restoration area is restored, and the restoration order among the remaining sub-restoration areas is random; the conditions for setting the preliminary restoration area are: areas with better habitat conditions and / or areas with better ecological background conditions, the habitat conditions and ecological background conditions are obtained based on the analysis and survey in step S1, and the habitat conditions and ecological background conditions that come first are defined as better habitat conditions and ecological background conditions; other sub-restoration areas need to have the water flow propagation dynamics of submerged plant propagules.

[0012] In a preferred embodiment of the present invention, in the lake natural ecological restoration method S3, each sub-restoration area is divided into a core area located at the center and a first buffer zone set around the core area; the core area is used to replant submerged plants, and the first buffer zone is used to plant floating-leaved plants, providing relatively stable habitat conditions for the core area; when the coverage rate of the submerged plant community in the core area is ≥60%, and the propagules produced by the submerged plants in the core area can spread and establish themselves in the first buffer zone, the first buffer zone is removed or partially removed, and a second buffer zone is re-established outside the first buffer zone; when the coverage rate of the aquatic plant community in the sub-restoration area is ≥60%, and the propagules produced by the submerged plants in the sub-restoration area can spread and establish themselves in the second buffer zone, the second buffer zone is removed or partially removed, and a third buffer zone is re-established outside the second buffer zone; and so on, until the sum of the coverage areas of the aquatic plant communities reaches the preset proportion of the total area of ​​the lake to be restored.

[0013] As a preferred embodiment of the present invention, the lake natural ecological restoration method begins with the sum of the areas of all sub-restoration areas accounting for 5-20% of the total area of ​​the lake to be restored; in S5, the preset ratio is 30-50%.

[0014] As a preferred embodiment of the present invention, in the lake natural ecological restoration method, in S3, when carrying out ecological restoration on all sub-restoration areas, based on the analysis of historical ecological data of the lake to be restored and the current status survey of the ecosystem in S1, a variety of adaptive submerged plants are introduced, and different submerged plants are distributed and planted in patches or mixed manner.

[0015] As a preferred embodiment of the present invention, in the lake natural ecological restoration method, S2, the pioneer plant buffer zone includes at least one group of floating-leaved plant zones, and each group of floating-leaved plant zones includes at least one floating-leaved plant zone; a floating-leaved plant zone refers to a strip-shaped area where floating-leaved plants are continuously planted; each floating-leaved plant zone in each group is perpendicular to a prevailing wind direction and is spaced apart along the path of the prevailing wind direction.

[0016] Specifically, based on the prevailing wind direction over the lake to be restored, multiple groups of floating-leaved plant belts can be set up, with each group corresponding to a prevailing wind direction. Therefore, the multiple groups of floating-leaved plant belts may intersect in a grid pattern, partially intersect, or be set up independently of each other, depending on the current prevailing wind direction of the lake to be restored.

[0017] In a preferred embodiment of the present invention, in the lake natural ecological restoration method, S2, the distance between the sub-restoration area and its adjacent floating-leaved plant belt is ≥200m; the floating-leaved plant belts in each group are set at intervals of 2-3km; and the width of each floating-leaved plant belt along the prevailing wind direction is 80-100m.

[0018] As a preferred embodiment of the present invention, in the lake natural ecological restoration method, in S3, the submerged plants are selected from one or more combinations of Potamogeton crispus, Vallisneria natans, Hydrilla verticillata, Myriophyllum spicatum, Ceratophyllum demersum, and Potamogeton malaianum; in S2 and S3, the floating-leaved plants are selected from one or more combinations of Water chestnut, Water lily, Water lily, Euryale ferox, Victoria water lily, and Nymphoides peltata.

[0019] In a preferred embodiment of the present invention, before S2, a pre-pollution reservoir and / or ecological purification zone are set up at the inlet of the lake to be restored in the lake natural ecological restoration method. For specific implementation methods of the lake pollution pre-pollution reservoir and ecological purification zone, please refer to the prior art.

[0020] (III) Beneficial Effects

[0021] The beneficial effects of this invention are as follows: This method for natural ecological restoration of lakes, after first analyzing historical ecological data and investigating the current state of the ecosystem to gain a more comprehensive understanding of the lake's condition, establishes a pioneer plant buffer zone at the center of the main wind and wave activity to reduce wind and waves, improve lake transparency, and provide a favorable water flow environment for subsequent sub-restoration area ecological restoration. Then, multiple sub-restoration areas are established within the lake to be restored. These sub-restoration areas stably generate submerged plant propagules, which are further dispersed and established by the natural flow of water, thereby expanding the restoration area. The overall restoration scheme utilizes the natural reproduction methods of submerged plants and water circulation, appropriately employing engineered ecological measures such as sub-restoration areas for guidance. Compared to existing technologies, this accelerates the restoration of the natural ecosystem. Its outstanding advantages over traditional artificial ecological restoration are lower investment, faster restoration, and stronger post-restoration ecological stability, making it more suitable for the restoration of medium to large-sized lakes. The strong post-restoration ecological stability is mainly reflected in the ability to quantitatively stock carnivorous fish and high-value river crabs, leveraging the multifunctionality and multi-service nature of the ecosystem.

[0022] Analyzing historical ecological data helps determine the location of sub-restored areas, select suitable submerged plants, and proactively avoid adverse factors during the planting process. Furthermore, developing specific plans based on the current state of the lake to be restored ensures targeted efforts and improves restoration efficiency.

[0023] Setting up pilot restoration zones in areas with better habitat conditions and / or better ecological baseline conditions can, on the one hand, provide experience for the restoration of other sub-restoration zones, and on the other hand, utilize the natural advantages of the pilot restoration zones to reserve some reproductive bodies and further improve the aquatic ecology.

[0024] Specifically, each sub-restoration area, through the establishment of a core area and a buffer zone, gradually expands the core area, accumulates propagules, and increases the restoration area under the protection of floating-leaved plants in the buffer zone. This method of artificial guidance combined with the gradual advancement of the aquatic environment has been applied to the ecological restoration of medium and large lakes with remarkable results.

[0025] When restoring all sub-restoration areas, the sum of the areas of all sub-restoration areas should account for 5-20% of the total area of ​​the lake to be restored, thus saving restoration costs; after restoration, the vegetation coverage can reach 30-50%, and the restoration effect is significant.

[0026] During the restoration process, a variety of adaptable submerged plants are introduced. These different submerged plants are distributed in patches or mixed patterns to promote competition among species, enabling survival of the fittest. On this basis, the community naturally evolves with changes in various conditions, resulting in a more stable underwater ecosystem. Specifically, a combination of plant species that function in different seasons is selected for the submerged plants, ensuring uninterrupted establishment and propagation throughout the seasonal transition.

[0027] The floating-leaved plant strips in each group are positioned perpendicular to a prevailing wind direction and spaced along that wind path. This effectively reduces water waves and facilitates the gradual expansion of the sub-recovery area. The floating-leaved plant strips in each group are spaced 2-3 km apart, and their width along the prevailing wind direction is 80-100 m. This helps reduce waves while minimizing costs. The distance between the sub-recovery area and its adjacent floating-leaved plant strips is ≥200 m to ensure sufficient dispersal space and adequate hydrodynamic force for the propagation organisms within the area.

[0028] Establish pre-pollution reservoirs and / or ecological purification zones at the inlets of lakes to be restored to reduce pollutants entering the lake, especially nitrogen and phosphorus nutrients, as much as possible, improve the water environment conditions of the lake area, and enhance the water quality of the water entering the lake. Attached Figure Description

[0029] Figure 1 This is a schematic diagram showing the distribution of the sub-recovery area and the pioneer plant buffer zone in Embodiment 1 of the present invention;

[0030] Figure 2 This is a schematic diagram of the pioneer plant buffer zone in Embodiment 1 of the present invention.

[0031] [Explanation of Labels in the Attached Image]

[0032] 1: Lakes awaiting restoration;

[0033] 2: Pioneer plant buffer zone; 21: Plant belt;

[0034] a: Prevailing wind direction. Detailed Implementation

[0035] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] This invention proposes a method for natural ecological restoration of lakes, addressing the technical problem of poor restoration results and high costs due to the lack of effective restoration schemes in the ecological restoration of large and medium-sized lakes. First, historical ecological data analysis and ecosystem status surveys are conducted to gain a more comprehensive understanding of the lake's condition. Then, a pioneer plant buffer zone is established at the center of the lake's main wind and wave activity to reduce wind and waves, improve lake transparency, and provide a favorable water flow environment for subsequent sub-restoration zone ecological restoration. Next, multiple sub-restoration zones are established within the lake to be restored. These zones stably generate submerged plant propagules, which are then further dispersed and established by natural water flow, thereby expanding the restoration area. The overall restoration scheme utilizes the natural reproduction methods of submerged plants and water circulation, appropriately guided by engineered ecological measures such as sub-restoration zones. Compared to existing technologies, this method accelerates the restoration of the natural ecosystem. Its outstanding advantages over traditional artificial ecological restoration are lower investment, faster restoration, and stronger ecological stability after restoration, making it more suitable for the restoration of medium and large-sized lakes. The strong ecological stability after restoration is mainly reflected in the ability to release carnivorous fish and high-value river crabs in a limited quantity, thus giving full play to the multifunctionality and multi-service nature of the ecosystem.

[0037] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0038] Example 1

[0039] This embodiment provides a method for the natural ecological restoration of lakes. Specifically, it takes the pilot project for the restoration of aquatic vegetation in Yangcheng Lake as an example. The project was launched in September 2021 and involves a total restoration area of ​​10,000 mu, accounting for 5.5% of the total area to be restored.

[0040] Specific implementation plan: (1) Preliminary investigation: Analysis of historical ecological data of the Yangcheng Lake area to be restored, including the location of the historical grass-covered area of ​​the lake, the evolution process of the historical grass-covered area and the main influencing factors involved in the evolution process; investigation of the current status of the ecosystem, including the meteorology, hydrology, water quality, substrate, biological group structure and the current status of the submerged plant propagule pool of the area to be restored. The above specific plan refers to the existing technology and will not be elaborated here.

[0041] (2) Based on the survey data, the water surface was first cleaned, including the removal of floating-leaved plants such as water chestnuts, invasive plants such as water hyacinths, decaying algae, and garbage; then, omnivorous and benthic fish were driven away, and external fish-proof nets were established; referring to Figure 1A total of 9 sub-restoration areas are set up within Lake 1 to be restored, specifically 2 on the east side (E1, E2), 3 in the middle (M1, M2, M3), and 4 on the west side (W1, W2, W3, W4).

[0042] (3) Selection of pilot restoration area: The E2 sub-restoration area, which has a relatively good ecological background and is located in the lake bend area, was selected as the pilot restoration area. That is, the first area to be restored was selected. The water depth within 100m of the shore in the E2 sub-restoration area is less than 2m, the seed bank abundance is high, and the background conditions are better than other sub-restoration areas. Then, various functional species were introduced into the core area in a timely manner, such as the overwintering plants Potamogeton crispus and the evergreen Vallisneria natans; the dominant species in spring, Vallisneria natans seeds and Hydrilla verticillata winter buds; and functional species in spring and summer, such as Myriophyllum spicatum, Ceratophyllum demersum, and Potamogeton malaianum. Different submerged plants were planted in small patches. Water chestnut seeds were sown in the buffer area. By the end of November of the same year, the core area had formed a good and stable ecosystem structure with abundant aquatic plants, and other sub-restoration areas played a demonstration role.

[0043] (4) Establish an effective pollution interception zone for the lake in sync with the pilot restoration area: reduce pollutants entering the lake as much as possible, improve the water environment conditions of the lake area, and set up submerged plant ecological zones in the W2 and W3 sub-restoration areas, including the rivers and inlets into the lake, agricultural non-point source pollution inlets and the shoreline, and the exposed slopes of the lakeside, to intercept and filter suspended solids in the water entering the lake, reduce various pollutants, and improve the water quality entering the lake.

[0044] (5) Construct a pioneer plant buffer zone, referring to... Figure 1 and Figure 2 In selected areas with relatively large winds and waves, water chestnut seeds were sown to establish a pioneer plant buffer zone 2 (located in the water chestnut distribution area shown in the figure). This pioneer plant buffer zone 2 consists of multiple water chestnut plant strips perpendicular to the prevailing wind direction. These strips 21 are spaced apart along the prevailing wind direction a, with intervals of 2-3 km between each strip. Each strip is 80-100 m wide along the prevailing wind direction. This effectively reduces wind and waves and provides a stable aquatic environment for the submerged plants. Note that the seed recovery area should maintain a distance of at least 200 m from adjacent water chestnut plant strips 21.

[0045] (6) Constructing an efficient "production-diffusion" system for submerged plant propagules: In the same year, for sub-recovery areas other than E2, submerged plant communities were rapidly established through enhanced artificial measures, specifically referring to the method used in E2, until the coverage rate of submerged plant communities was ≥60%. This was to enable the plant propagules in each sub-recovery area to drift and diffuse outwards with the aid of lake currents in the following summer and autumn, thereby expanding the germplasm resources in the entire water body. As a result, each sub-recovery area experienced varying degrees of propagule spillover and diffusion that year, resulting in an expansion of the restoration area. Among them, the diffusion and restoration area of ​​the three sub-recovery areas W2, M2, and E2 was the most significant. These three areas are close to the shore and have good hydrodynamics.

[0046] (7) Artificially guide each sub-restored area to carry out further spillover diffusion: After the core area and the outer expansion area in step (6) are generally the same as the core area and the buffer zone in step (3), after the coverage rate of submerged plant community in each sub-restored area is ≥60%, according to the wind and wave conditions of each sub-restored area, select to remove all or part of the water chestnuts in the buffer zone, and plant water chestnuts again outside the original buffer zone to form a new buffer zone. In this way, guide each sub-restored area to gradually expand the restoration area until the coverage rate of submerged plant community in the whole area (the overall lake to be restored) reaches 30-50% (including the original preparation coverage in the lake area), that is, the restoration work of the lake to be restored is completed.

[0047] Using natural forces to spread and plant submerged plants mainly relies on wind and waves to spread the propagules to suitable locations. This method can quickly, efficiently, and cost-effectively restore large areas of lakes.

[0048] In this Example 1, the pilot project for the restoration of aquatic vegetation in Yangcheng Lake has achieved good results. Taking the M2 sub-restored area as an example, according to the monitoring data and the comparison with the same period, the total phosphorus in the water quality was 0.069 mg / L in June 2021 and 0.026 mg / L in June 2022, which stably met the Class III water standard of lakes and reservoirs (0.05 mg / L). The vegetation coverage and water environment have been restored to different degrees.

[0049] The Yangcheng Lake aquatic vegetation restoration project commenced in September 2021. Within the same year, the overwintering plant Potamogeton crispus was propagated and spread from the sub-restored area with the water flow, forming a diffusion restoration area of ​​over 500 mu.

[0050] In 2022, propagules were also observed spreading with the water flow in other sub-recovery areas. The species that spread outward all had a strong ability to reproduce by breaking branches, including Myriophyllum spicatum and Ceratophyllum demersum.

[0051] After more than two years of restoration by 2023, the total vegetation area outside the restored area, formed by the overflow of submerged plant propagation material, exceeded 2,000-3,000 mu (approximately 133-200 hectares). With proper maintenance, it is expected to propagate at a faster rate and become a seed bank for the entire lake.

[0052] The main reasons for the restoration of aquatic vegetation outside the sub-restoration area of ​​Yangcheng Lake, in addition to the overflow of internal plant reproduction, also include the improvement of the surrounding water environment by the restoration area and the promoting effect of sediment settling in the sub-restoration area, which provides good habitat conditions for submerged plants.

[0053] According to the evaluation report on the actual effect of aquatic vegetation planting in the project (September 2023) by a third-party professional unit (China Institute of Water Resources and Hydropower Research), seven new submerged plant species were added, water transparency increased by 52.9% compared with the same period before restoration, and the overall aquatic vegetation coverage reached 59.4%. In 2023, the water quality at the national control point in the center of Yangcheng Lake reached Class III, with an annual average total phosphorus concentration of 0.046 mg / L. With the increase in aquatic vegetation coverage, water transparency, and aquatic biodiversity in the restoration area, the water quality in the restoration area has improved, achieving the project objectives.

[0054] Furthermore, according to data from the National Water Quality Monitoring Platform, the average concentration of pollutants at the national standard monitoring section in the center of Yangcheng Lake from January to April 2024 was 0.044 mg / L, significantly lower than the average concentrations in the same period of 2022 (0.087 mg / L) and 2023 (0.049 mg / L), showing a year-on-year improvement trend. Moreover, the water quality improved from Class IV to Class III, and the self-purification capacity and biodiversity of the lake area's ecosystem have been continuously enhanced.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for restoring the natural ecology of a lake, characterized in that, Includes the following steps: S1. Conduct historical ecological data analysis and ecosystem status surveys for lakes to be restored; S2. Based on the analysis and investigation results of step S1, plant floating-leaved plants in the central area of ​​the lake to be restored and / or the center of the wind and waves to form a pioneer plant buffer zone. S3. Based on the analysis and investigation results of step S1, at least one sub-restoration area is set up in the lake to be restored, and ecological restoration is carried out on all sub-restoration areas in a preset order. The ecological restoration measures include constructing a stable primary submerged plant community in each sub-restoration area; wherein the primary submerged plant community can stably produce propagules. S4. The propagules generated in each sub-restoration area can naturally spread and establish themselves in other locations outside the sub-restoration area within the lake to be restored with the help of natural forces, forming a stable secondary submerged plant community to expand the completed restoration area; the natural forces include water flow, wind and waves, fish activity and human water activities; S5. The propagules produced by the secondary and primary submerged plant communities spread and establish themselves in other locations within the lake to be restored with the help of natural forces. Over time, the coverage area of ​​the submerged plant communities reaches the preset proportion of the total area of ​​the lake to be restored. In S2, the pioneer plant buffer zone includes at least one set of floating-leaved plant zones, and each set of floating-leaved plant zones includes at least one floating-leaved plant zone; a floating-leaved plant zone refers to a strip-shaped area where floating-leaved plants are continuously planted. Each floating-leaved plant strip in each group is perpendicular to a prevailing wind direction and spaced apart along the path of that prevailing wind direction; The distance between the sub-recovery area and its adjacent floating-leaved plant zone is ≥200m; The floating-leaved plant strips in each group are spaced 2-3 km apart; Each floating-leaved vegetation strip is 80-100m wide along the prevailing wind direction; In S3, each sub-recovery area is divided into a core area located in the center and a first buffer zone set around the core area; the core area is used to replant submerged plants, and the first buffer zone is used to plant floating-leaved plants. The first buffer zone provides relatively stable habitat conditions for the core area. When the coverage rate of submerged plant communities in the core area is ≥60%, and the propagules produced by the submerged plants in the core area can spread and establish themselves in the first buffer zone, the first buffer zone shall be dismantled or partially dismantled, and a second buffer zone shall be re-established outside the first buffer zone. When the submerged plant community coverage rate in the sub-restoration area is ≥60%, and the propagules produced by the submerged plants in the sub-restoration area can spread and establish themselves in the second buffer zone, the second buffer zone shall be dismantled or partially dismantled, and a third buffer zone shall be re-established outside the second buffer zone. This process continues until the sum of the aquatic plant community coverage area reaches the preset proportion of the total area of ​​the lake to be restored.

2. The lake natural ecology restoration method as described in claim 1, characterized in that, In S1, the analysis of historical ecological data includes the location of the historical grassland area of ​​the lake to be restored, the evolution process of the historical grassland area, and the main influencing factors involved in the evolution process. The current status of the ecosystem includes the meteorological, hydrological, water quality, substrate, biological community structure, and submerged plant propagule pool status of the lakes to be restored; The following information was obtained through the above analysis and investigation: prevailing wind direction, location of the center of the waves, adaptive floating-leaved plant species that grow in the lake to be restored, adaptive submerged plant species that survive in the lake to be restored and can stably produce propagules, regional habitat conditions and ecological background conditions of the lake to be restored, and the location of historically grassy areas.

3. The lake natural ecology restoration method as described in claim 1, characterized in that, In S3, based on the analysis of historical ecological data of the lakes to be restored in S1 and the survey of the current status of the ecosystem, the distribution locations of the sub-restoration areas are set; When the number of sub-recovery regions is ≥2; Different sub-restorement areas will undergo ecological restoration in the following preset order: The first sub-restoration area to undergo ecological restoration is designated as the pilot restoration area. Restoration of the remaining sub-restoration areas will begin only after the pilot restoration area has been restored, and the restoration order among the remaining sub-restoration areas is random. The conditions for setting up the preliminary restoration zone are: areas with better habitat conditions and / or areas with better ecological background conditions. The habitat conditions and ecological background conditions are obtained based on the analysis and investigation in step S1. The habitat conditions and ecological background conditions that appear earlier are defined as better habitat conditions and ecological background conditions. Other sub-recovery areas need to have the water flow propagation power of submerged plant propagules.

4. The lake natural ecology restoration method as described in claim 1, characterized in that, In S3 At the start of restoration in all sub-restorement areas, the sum of the areas of all sub-restorement areas should account for 5-20% of the total area of ​​the lake to be restored. In S5, the preset ratio is 30-50%.

5. The lake natural ecology restoration method as described in claim 1, characterized in that, In S3, when carrying out ecological restoration on all sub-restoration areas, based on the analysis of historical ecological data of the lakes to be restored in S1 and the current status survey of the ecosystem, a variety of adaptive submerged plants are introduced, and different submerged plants are distributed and planted in patches or mixed ways.

6. The lake natural ecology restoration method as described in claim 1, characterized in that, In S3 The submerged plants are selected from one or more combinations of the following: Potamogeton crispus, Lithocarpus stenoptera, Vallisneria natans, Hydrilla verticillata, Myriophyllum spicatum, Ceratophyllum demersum, and Potamogeton malaianus. In S2 and S3, the floating-leaved plant is selected from one or more combinations of water chestnut, water lily, water lily, foxnut, giant water lily, and water lily.

7. The lake natural ecology restoration method as described in claim 1, characterized in that, Prior to S2, a pre-pollution reservoir and / or ecological purification zone will be set up at the inlet of the lake to be restored.

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