Method for repairing peripheral mud flat of artificial mangrove forest

Abstract

The invention discloses a method for repairing a peripheral mud flat of an artificial mangrove forest. The method comprises the steps that S1, the position of a mud flat repairing area is determined; s2, establishing a mud flat repair area; according to natural fluctuation and ebb tide of seawater, activities of fishes and benthonic animals can be increased by utilizing the mud flat repairing area, and mud flat soil is disturbed frequently and kept loose; a series of problems of mud flat adhesion, limited survival of fishes and benthonic animals, lack of bird food, low biodiversity and the like caused by the fact that the artificial mangrove forest afforestation mainly adopts songarus apetala are solved, and a food chain of an artificial mangrove forest ecological system is repaired, so that the biodiversity of the artificial mangrove forest is effectively improved; and ecological system quality and stability.

Description

Technical Field

[0001] The invention relates to the technical field of artificial mangrove ecological restoration, and in particular to a method for restoring a tidal flat surrounding an artificial mangrove. Background Art

[0002] As one of the important types of marine wetlands, mangrove wetlands play an extremely important role in protecting marine ecology. Mangrove wetlands not only have multiple ecological functions such as purifying water quality, reducing red tides, consolidating beaches and embankments, and promoting siltation and land reclamation, but are also important habitats for a large number of endangered and rare water birds, and important breeding grounds for aquatic organisms such as fish, shrimp, crabs and shellfish. In the 1950s, the area of ​​mangroves in my country was about 50,000 hm2. 2 , due to the impact of coastal zone development and resource utilization, it dropped to 22,000 hm2 in 2001. 2 .

[0003] Since 2001, the state has attached great importance to the protection and restoration of mangroves. In the process of large-scale mangrove restoration in the country, some exotic species have been introduced as restoration species. Among them, Sonneratia apetala has become the most important mangrove wetland restoration species, accounting for 95% of all restoration species. Since 1998, Sonneratia apetala has been widely introduced and expanded along the coast of South China, with a total planting area of ​​3,800 hm2. 2 However, the growth of Sonneratia apetala promotes the clayification of tidal flat soil, resulting in serious clayification of the tidal flat soil around the artificial mangroves dominated by Sonneratia apetala, reduced air permeability and permeability, and restricted air and water circulation. In addition, after the tidal flat soil becomes clayey, the mechanical strength increases and the soil becomes more compact, making it difficult for fish and benthic animals to move, severely restricting their survival and reproduction, which in turn leads to a significant decrease in the amount of food for beach water birds. Ultimately, the food chain of the mangrove wetland is destroyed, which greatly affects the stability and integrity of the ecosystem, resulting in an increase in the area of ​​mangroves but a shrinking of biodiversity.

[0004] In order to solve the above problems, the existing technologies mostly start with the transformation of Sonneratia apetala, improve the Sonneratia apetala forest stands by pruning and light-transmitting felling, and plant shade-tolerant tree-type native mangrove plants under the forest to gradually replace Sonneratia apetala. However, there is still a lack of effective restoration technology solutions for the tidal flats with severely clay-like soil outside artificial mangroves. Therefore, the present invention provides a method for repairing tidal flats outside artificial mangroves, which quickly improves the quality of tidal flats, repairs the habitats of fish and benthic animals, increases the amount of food for beach waterfowl, and repairs the food chain of the artificial mangrove ecosystem, thereby effectively improving the biodiversity, ecosystem quality and stability of artificial mangroves. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a method for repairing the tidal flats outside an artificial mangrove forest.

[0006] A method for repairing a beach outside an artificial mangrove forest comprises the following steps:

[0007] S1. Determine the location of the tidal flat restoration area;

[0008] The tidal flat restoration area is set on the outer beach surface between the artificial mangrove and the sea surface, and the distance between the tidal flat restoration area and the artificial mangrove is set to L1; wherein the tidal flat restoration area includes a first bottom mud loosening area, a bottom mud stacking area and a second bottom mud loosening area which are sequentially arranged from far to near in the direction of the artificial mangrove;

[0009] S2. Establishment of tidal flat restoration areas;

[0010] S2-1, setting a fence on the outer beach, wherein the fence is set in an arc shape toward the artificial mangrove forest, and the first bottom mud excavation area and the bottom mud stacking area are separated by the fence;

[0011] S2-2, loosening the bottom mud in the first bottom mud loosening area and the second bottom mud loosening area, and piling a portion of the loosened bottom mud in the bottom mud piling area;

[0012] S2-3, micro-topography is respectively performed on the first bottom mud loosening area, the bottom mud stacking area and the second bottom mud loosening area, and the micro-topography shaping includes setting up a plurality of tidal pools.

[0013] Note: By determining the location of the tidal flat restoration area and setting up the fences inside it in the above method, it is possible to block dead branches, fish, shrimps, crabs and other aquatic organisms brought in by the tide during natural ebb and flow of the tide, thereby attracting birds, so as to establish a small ecosystem on the beach of the tidal pool. When the activities of fish and benthic animals increase, the tidal flat soil will be frequently disturbed to keep it loose, thereby solving a series of problems caused by the artificial mangrove afforestation dominated by Sonneratia apetala, such as the adhesion of the tidal flat, the limited survival of fish and benthic animals, the lack of food for birds, and the low biodiversity. The food chain of the artificial mangrove ecosystem is restored, thereby effectively improving the biodiversity, ecosystem quality and stability of the artificial mangrove.

[0014] Furthermore, the fence includes pine wood piles and silt-blocking ropes for connecting the pine wood piles.

[0015] Note: The fence structure formed by the above-mentioned pine wood piles is more practical.

[0016] Furthermore, the arc has an angle of 45° to 90°.

[0017] Note: The arc formed by the above angles can make the tidal flat restoration area act as a fence for the artificial mangroves, helping to form a small ecosystem.

[0018] Furthermore, the first bottom mud loosening area, the bottom mud stacking area and the second bottom mud loosening area are all the same in area and width, and their lengths are all equal to the arc length of the fence.

[0019] Note: The above-mentioned area division can be used to introduce tidal organisms into the tidal flat restoration area, and through the setting of fences and tidal pools, a more suitable living environment can be provided for these aquatic organisms.

[0020] Furthermore, the arc length of the fence is L2, the width of the first bottom mud excavation area is L3, and L1, L2, and L3 satisfy: L2≤L1≤L3; the above L2 can be taken as 1000m.

[0021] Note: The above lengths are set to make the division of tidal flat restoration areas and the realization of the functions of each area more reasonable and practical.

[0022] Furthermore, the length of the pine wood pile is greater than or equal to 6m and less than or equal to 20m, the diameter of the pine wood pile is 0.1-0.15m, the pine wood pile is installed underground, the height of the pine wood pile above the ground is 0.3m, and the interval between every two pine wood piles is 0.3-0.5m.

[0023] Note: The above length settings are relatively appropriate. Existing research has shown that under this value, the effect of the tidal flat restoration area is better.

[0024] Furthermore, the method includes S2-4, establishing a plurality of tidal flat restoration areas, each of which is spaced apart by L4; 2L3≤L4≤3L3.

[0025] Note: The above range setting can make the surrounding effect of multiple tidal flat restoration areas on the outer restoration of artificial mangroves better. If it exceeds this range, it may lead to increased costs or no significant increase in the effect of soil treatment.

[0026] Furthermore, the plurality of tidal pools provided in the first sludge excavation area and the second sludge excavation area meet the following requirements: the tidal pool has a depth of 0.1 to 0.3 m and an area of ​​10 to 50 m 2 The height of the pile around the tidal pool is 0.1 to 0.3m.

[0027] Furthermore, the multiple tidal pools set up in the bottom mud storage area meet the following requirements: the tidal pool depth is 0.3-0.5m and the area is 10-50m 2 The height of the pile around the tidal pool is 0.3 to 0.4m.

[0028] Note: Through the differentiated design of the depth of the tidal pool in the above-mentioned bottom mud storage area and the tidal pools in the first bottom mud dredging area and the second bottom mud dredging area, aquatic organisms in the seawater can exist in these tidal pools of different depths, and these tidal pools are suitable for the survival of aquatic organisms.

[0029] Furthermore, the digging depth for loosening the bottom mud in S2-2 is 0.1 to 0.5 m.

[0030] Note: The excavation depth in the above range is relatively appropriate. If the excavation continues, it may increase the cost and make it more difficult to shape the tidal pools in the first and second bottom mud loosening areas.

[0031] Furthermore, in the bottom mud stacking area, the height of the bottom mud stacking is 0.1 to 0.5 m, and a slowing slope is set toward the direction of the artificial mangroves.

[0032] Note: The above stacking direction can reduce the direct impact of seawater on the bottom mud.

[0033] The beneficial effects of the present invention are:

[0034] According to the natural ebb and flow of tide, the present invention can use the beach restoration area to intercept dead branches brought in by the tide, achieve the effect of promoting siltation, ensure the quality of the beach, and intercept aquatic organisms such as fish, shrimps and crabs at low tide to retain food for waterfowl; loosening the bottom mud is conducive to the activities of fish and benthic animals, which helps them survive and reproduce, and will eventually increase the amount of food for waterfowl on the beach; in addition, after the activities of fish and benthic animals increase, the beach soil will be frequently disturbed to keep it loose. This technical solution solves a series of problems such as beach adhesion caused by artificial mangrove afforestation dominated by Sonneratia apetala, limited survival of fish and benthic animals, lack of bird food, and low biodiversity, and repairs the food chain of the artificial mangrove ecosystem, thereby effectively improving the biodiversity, ecosystem quality and stability of the artificial mangrove. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a plan view of the structure in the tidal flat restoration area of ​​the present invention;

[0036] Figure 2 It is a schematic cross-sectional view of a row of pinewood piles in a tidal flat restoration area in the present invention;

[0037] Figure 3 It is a plan view schematically showing the arrangement of multiple tidal flat restoration areas in the present invention. DETAILED DESCRIPTION

[0038] In order to further illustrate the method adopted by the present invention and the effect achieved, the technical solution of the present invention will be clearly and completely described in combination with experiments below.

[0039] Example 1: Figure 1 As shown, a method for repairing the tidal flats outside an artificial mangrove forest comprises the following steps:

[0040] A method for repairing a beach outside an artificial mangrove forest comprises the following steps:

[0041] S1. Determine the location of the tidal flat restoration area;

[0042] The tidal flat restoration area is set on the outer beach surface between the artificial mangroves and the sea surface, and the distance between the tidal flat restoration area and the artificial mangroves is set to L1; wherein the tidal flat restoration area includes a first bottom mud loosening area, a bottom mud stacking area and a second bottom mud loosening area which are arranged in sequence from far to near in the direction of the artificial mangroves, such as Figure 3 As shown;

[0043] S2. Establishment of tidal flat restoration areas;

[0044] S2-1, a fence is set on the outer beach, the fence is set in an arc shape toward the artificial mangrove, and the first bottom mud excavation area and the bottom mud stacking area are separated by the fence; the fence includes pine wood piles and silt-blocking ropes for connecting the pine wood piles; the arc angle is 60°, such as Figure 2 As shown;

[0045] S2-2, loosen the bottom mud in the first bottom mud excavation area and the second bottom mud excavation area, and pile a part of the loosened bottom mud in the bottom mud pile area; the excavation depth of the loosened bottom mud in S2-2 is 0.2m; in the bottom mud pile area, the height of the bottom mud is 0.3m, and a slowdown slope is set towards the direction of the artificial mangrove;

[0046] S2-3, micro-topography is respectively performed on the first bottom mud loosening area, the bottom mud stacking area and the second bottom mud loosening area, and the micro-topography shaping includes setting up a plurality of tidal pools.

[0047] The arc length of the fence is L2, the width of the first bottom mud excavation area is L3, and L1, L2, and L3 satisfy: L2≤L1≤L3; the above L2 is 1000m.

[0048] S2-4, establish multiple tidal flat restoration areas, the interval between each tidal flat restoration area is L4; 2L3≤L4≤3L3.

[0049] The first bottom mud excavation area, the bottom mud stacking area and the second bottom mud excavation area are all the same in area and width, and their lengths are all equal to the arc length of the fence.

[0050] The length of the pine wood pile is greater than or equal to 6m, the diameter of the pine wood pile is 0.13m, the pine wood pile is installed underground, and the height of the pine wood pile above the ground is 0.3m; the interval between every two pine wood piles is 0.4m.

[0051] The multiple tidal pools provided in the first sludge excavation area and the second sludge excavation area meet the following requirements: the tidal pool has a depth of 0.2 m and an area of ​​30 m 2 , the height of the pile around the tidal pool is 0.2m;

[0052] The multiple tidal pools set up in the bottom mud storage area meet the following requirements: the tidal pool depth is 0.4m and the area is 30m 2 The height of the pile around the tidal pool is 0.35m.

[0053] Example 2

[0054] This embodiment provides a preferred repair method of the present invention:

[0055] (1) Set up ecological buffer zones around the micro-topography: such as planting salt-tolerant herbaceous plants to enhance the stability and biodiversity of the ecosystem. Plant selection: Select a variety of salt-tolerant and flood-tolerant native plants to build a multi-layered vegetation structure, including herbaceous plants, shrubs and trees, to provide a variety of habitats.

[0056] (2) Artificial reefs: Create artificial reefs in the beach restoration area near the sea to provide habitats for birds and marine life. For example, use natural or degradable materials to build artificial reefs to reduce negative impacts on the environment. Biological attachment: Promote the attachment and growth of marine life such as corals and shellfish on artificial reefs to accelerate the naturalization of the ecosystem.

[0057] (3) Water level regulation: Proper regulation of the water level of tidal pools or ditches, or the depth of tidal pools or ditches, can prevent further soil clayification caused by long-term water accumulation.

[0058] (4) Constructing ecological ditches: Constructing criss-crossing ecological ditches on the tidal flats will help the flow of water and soil infiltration.

[0059] Specifically, in ecological restoration projects, parameters such as tidal pool depth or water level, ecological ditch depth, etc. can be adjusted according to different soil viscosities. Usually, multiple factors need to be considered, including soil physical properties, hydrological conditions, ecological needs, etc. At present, it is impossible to directly describe this process by calculation, because it involves the interaction between complex natural systems and human intervention. The present invention provides a more practical method, simplifies the system function, and can provide a boundary design method for tidal pool depth design and ecological ditch depth design. Designing according to this method can improve the effect of restoration.

[0060] Example: Tidal pool depth design:

[0061] D=k·τ+A

[0062] Where D is the design depth of the tidal pool; k is an empirical coefficient that needs to be adjusted according to specific circumstances; τ is the soil viscosity; and A is the tidal amplitude (the height difference of the tide, which affects the maximum and minimum values ​​of the water depth).

[0063] Ecological ditch depth design:

[0064]

[0065] Where D is the ditch depth, K is the soil permeability, representing the infiltration capacity of the soil; Q is the design drainage; B is the ditch width, and i is the hydraulic slope.

[0066] Example 3

[0067] The difference between this embodiment and embodiment 1 is that the central angle of the arc of the fence towards the artificial mangrove is 45°; the length of the pine wood pile is 7m, the diameter of the pine wood pile is 0.1m, and the interval between every two pine wood piles is 0.3m. The depth of the multiple tidal pools set in the first bottom mud excavation area and the second bottom mud excavation area is 0.1m, and the area is 50m 2 The height of the pile around the tidal pool is 0.1m; the multiple tidal pools set up in the bottom mud storage area meet the following requirements: the tidal pool depth is 0.3m and the area is 10m 2 The height of the pile around the tidal pool is 0.3m; the digging depth for loosening the bottom mud is 0.1m; in the bottom mud stacking area, the height of the bottom mud stacking is 0.5m.

[0068] Example 4

[0069] The difference between this embodiment and embodiment 1 is that the central angle of the arc of the fence towards the artificial mangrove is 90°; the length of the pine wood pile is 8m, the diameter of the pine wood pile is 0.15m, and the interval between every two pine wood piles is 0.5m. The depth of the multiple tidal pools set in the first bottom mud excavation area and the second bottom mud excavation area is 0.3m, and the area is 10m 2 The height of the pile around the tidal pool is 0.3m; the multiple tidal pools set up in the bottom mud storage area meet the following requirements: the tidal pool depth is 0.5m and the area is 50m 2 The height of the pile around the tidal pool is 0.4m; the digging depth for loosening the bottom mud is 0.5m; in the bottom mud stacking area, the height of the bottom mud stacking is 0.1m.

[0070] Experimental example:

[0071] 20 hm2 of peripheral tidal flat restoration was carried out in an artificial mangrove wetland in a certain province and island 2 The artificial mangroves in the project area are mainly composed of Sonneratia apetala. The mudflat soil is seriously clay-like, fish and benthic animals cannot move, and the abundance is extremely low, resulting in a lack of food for waterfowl on the beach and a shrinking diversity of waterfowl. A total of 7 tidal flat restoration areas have been established on the outer tidal flats, each of which is about 250m apart. The following projects are implemented in each tidal flat restoration area: a row of arc-shaped pinewood piles with an arc length of 1km and a central angle of 90° is driven on the beach. After driving the piles, 0.3m is exposed on the beach. The length of the pinewood piles used is 6m, the pile diameter is 0.1m, and the interval between every two pinewood piles is 0.5m. A silt-blocking rope is used between every two pinewood piles; the bottom mud on the outside of the pinewood pile row (near the sea surface) is excavated: from the pile driving Starting from the position, loosen the bottom mud within a range of 100m; loosen the bottom mud on the inner side of the pine wood pile row (near the artificial mangrove side): starting from a position 100m away from the pine wood pile row, loosen the bottom mud within a range of 100m; during the loosening of the bottom mud, part of the excavated bottom mud is piled on the inner side of the pine wood pile row (near the artificial mangrove side), the range of bottom mud stacking is from the piling position, within 100m of the inner side of the pine wood pile row (near the artificial mangrove side), and the height of the bottom mud stacking is 0.05~0.1m.

[0072] After the project was completed, surveys showed that the number of bird species in the project area increased by 30. Biodiversity surveys for three consecutive years showed that the number of bird species in the project area increased by 142 species, the richness of aquatic organisms increased by about 35%, and the output of aquatic products in the area reached 6 times that of nearby waters.

[0073] The above-described embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or changes made by those skilled in the art based on the present invention are within the protection scope of the present invention. The protection scope of the present invention shall be subject to the claims.

Claims

1. A method for repairing the tidal flats surrounding artificial mangroves, characterized in that: The following steps are involved: S1. Determine the location of the tidal flat restoration area; The tidal flat restoration area is set on the outer beach surface between the artificial mangrove and the sea surface, and the distance between the tidal flat restoration area and the artificial mangrove is set to L1; wherein the tidal flat restoration area includes a first bottom mud loosening area, a bottom mud stacking area and a second bottom mud loosening area which are sequentially arranged from far to near in the direction of the artificial mangrove; S2. Establishment of tidal flat restoration areas; S2-1, setting a fence on the outer beach, wherein the fence is set in an arc shape toward the artificial mangrove forest, and the first bottom mud excavation area and the bottom mud stacking area are separated by the fence; S2-2, loosening the bottom mud in the first bottom mud loosening area and the second bottom mud loosening area, and piling a portion of the loosened bottom mud in the bottom mud piling area; S2-3, micro-topography is respectively performed on the first bottom mud loosening area, the bottom mud stacking area and the second bottom mud loosening area, and the micro-topography shaping includes setting up a plurality of tidal pools.

2. The method for repairing the tidal flat surrounding an artificial mangrove forest as claimed in claim 1, characterized in that: The fence includes pinewood stakes and silt-blocking ropes for connecting the pinewood stakes.

3. A method for repairing the tidal flat surrounding an artificial mangrove forest as claimed in claim 2, characterized in that: The arc has an angle of 45° to 90°.

4. The method for repairing the tidal flat surrounding an artificial mangrove forest as claimed in claim 2, characterized in that: The first bottom mud excavation area, the bottom mud stacking area and the second bottom mud excavation area are all the same in area and width, and their lengths are all equal to the arc length of the fence.

5. The method for repairing the tidal flat surrounding an artificial mangrove forest as claimed in claim 2, characterized in that: The arc length of the fence is L2, the width of the first bottom mud excavation area is L3, and L1, L2, and L3 satisfy: L2≤L1≤L3.

6. A method for repairing the tidal flats surrounding artificial mangroves as claimed in claim 5, characterized in that: The length of the pine wood pile is greater than or equal to 6m and less than or equal to 20m, the diameter of the pine wood pile is 0.1-0.15m, the pine wood pile is installed underground, and the height of the above-ground pine wood pile is 0.3m.

7. The method for repairing the tidal flat surrounding an artificial mangrove forest as claimed in claim 5, characterized in that: Including S2-4, establishing multiple tidal flat restoration areas, the interval between each tidal flat restoration area is L4; 2L3≤L4≤3L3.

8. The method for repairing the tidal flat surrounding an artificial mangrove forest as claimed in claim 1, characterized in that: The multiple tidal pools provided in the first sludge excavation area and the second sludge excavation area meet the following requirements: the tidal pool depth is 0.1 to 0.3 m and the area is 10 to 50 m 2 The height of the pile around the tidal pool is 0.1 to 0.3m.

9. The method for repairing the tidal flat surrounding an artificial mangrove forest as claimed in claim 1, characterized in that: The multiple tidal pools set up in the bottom mud storage area meet the following requirements: the tidal pool depth is 0.3-0.5m and the area is 10-50m 2 The height of the pile around the tidal pool is 0.3 to 0.4m.

10. The method for repairing the tidal flat surrounding an artificial mangrove forest as claimed in claim 1, characterized in that: The digging depth of loosening the bottom mud in S2-2 is 0.1 to 0.5 m.

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