A mangrove mudflat suitable for forestation construction method based on lifting elevation

Abstract

The present application relates to the technical field of planting and repairing of mudflat mangrove, and discloses a method for constructing mangrove mudflat suitable land based on lifting elevation, which comprises the following steps: S1, constructing mudflat suitable land: constructing suitable land according to target elevation; S2, constructing primary protection structure: constructing wooden pile protection structure on the sea side of suitable land; S3, constructing secondary protection structure: constructing oyster reef protection layer between the periphery of suitable land and the wooden pile protection structure; S4, constructing ecological dam: constructing ecological dam between the primary protection structure and the secondary protection structure, forming water storage area between the ecological dam and the secondary protection structure, and the ecological dam is further provided with a plurality of planting areas for filling planting biological nutrients. The present application can reduce the adverse effects of wind, wave and tide on mudflat and mangrove seedlings, improve the effect of mud and dam fixation, improve the survival rate of mangrove, and optimize the marine ecological environment.

Description

A method for constructing suitable mangrove tidal flat afforestation land based on elevation Technical Field

[0001] This invention relates to the field of mangrove planting and restoration technology, specifically to a method for constructing suitable mangrove tidal flats based on elevation. Background Technology

[0002] Mangroves are wetland woody plant communities, mainly composed of evergreen trees or shrubs, growing in the intertidal zone of tropical and subtropical coasts. They play a vital role in purifying seawater, preventing wind and waves, sequestering and storing carbon, and maintaining biodiversity, earning them the reputation of "coastal guardians" and "oceanic lungs." Currently, my country is actively investing heavily in mangrove restoration to revitalize coastal wetland ecosystems, particularly in the outer mudflats of coastal engineering projects that previously lacked vegetation cover and regeneration capacity. Adhering to the principles of "respecting nature and scientific restoration," and following the succession patterns of mangrove ecosystems, restoration methods such as artificially constructing suitable afforestation areas are used to increase vegetation coverage and create natural and ecological new coastlines.

[0003] However, since these coastal mudflats are often not suitable for afforestation, the biggest problem in restoration is that the mudflat elevation is too low for mangrove growth, and natural factors such as coastal winds, waves, and tides continuously cause the loss of sediment from the mudflats, thus affecting the growth and survival rate of mangrove seedlings. Existing technologies offer some solutions to the problem of wave dissipation and mudflat stabilization. For example, Chinese invention patent CN113774858B discloses a protective structure for mudflats where mangrove seedlings grow. By setting up protective components and water-retaining structures between the mudflats and the ocean, the water-retaining structure prevents the sediment from being carried away, ensuring mudflat stability and stabilizing the mudflats. Furthermore, the mesh structure of the wave-dissipating net reduces the waves entering the mudflats through the first wave-dissipating space, thereby reducing large waves and weakening the water flow.

[0004] While the aforementioned existing technologies can play a certain role in wave reduction and beach stabilization, the following technical problems still exist in practical applications: the protective structure is relatively complex and requires a large amount of manpower, material resources, and financial resources to construct; the use of a large amount of netting, hooks, ropes, and other materials may cause pollution to the marine environment and damage to marine life; in addition, after the mangrove seedlings grow into a forest, in order to reduce the interference of the protective structure on the marine environment, it is necessary to spend manpower to recycle and dismantle it, which is uneconomical and environmentally unfriendly. Summary of the Invention

[0005] The present invention aims to provide a method for constructing suitable mangrove tidal flats based on elevation, so as to reduce the adverse effects of wind, waves and tides on tidal flats and mangrove seedlings, improve the effect of mud stabilization and dike reinforcement, increase the survival rate of mangroves, and optimize the marine ecological environment.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a method for constructing suitable mangrove tidal flats for afforestation based on elevation, comprising the following steps:

[0007] S1. Constructing suitable afforestation land on tidal flats: Constructing suitable afforestation land according to the target elevation;

[0008] S2. Constructing a primary protective structure: Constructing a timber pile protective structure on the seaside of suitable afforestation land;

[0009] S3. Construct a secondary protective structure: Construct an oyster reef protective layer between the perimeter of the suitable afforestation land and the wooden pile protective structure;

[0010] S4. Construct an ecological dam: Construct an ecological dam between the primary protection structure and the secondary protection structure. A water storage area is formed between the ecological dam and the secondary protection structure. Several planting areas are also set up on the ecological dam to fill the planting biological nutrients.

[0011] Technical Principle: During high tide, seawater successively submerges the ecological dike and secondary protective structure, replenishing the water storage area. Simultaneously, seawater enters suitable planting areas to irrigate mangrove seedlings. Furthermore, the submersion of the ecological dike during high tide attracts marine plankton, shellfish, and other organisms, which then form a micro-ecosystem with the biological nutrients in the planting area. When the tide recedes, some marine life and nutrients die, while others in the water storage area continue to survive. When waves occur, the dead biological nutrients are pushed to suitable planting areas by the impact of the waves, thus becoming nutrients for mangrove seedling growth. Additionally, the water storage area slows down the receding tide, allowing some seawater to be stored. Some of this stored seawater can then enter suitable planting areas, providing a moist living environment for mangrove seedlings and improving their early survival rate. When waves occur, seawater is continuously pushed into the water storage area, replenishing it.

[0012] Beneficial effects:

[0013] 1. Multi-layered protective structure enhances wave dissipation and dike stabilization: Secondary protective structures, ecological dikes, and primary protective structures are sequentially set up around the suitable afforestation area, which have a multi-layered effect of reducing wind and waves. The wooden pile protective structure and ecological dike first buffer the waves to weaken the water flow, which can effectively reduce the erosion of the suitable afforestation area by wind and waves, while protecting seedlings and reducing the occurrence of seedlings falling over due to wind and waves. When the tide recedes, the oyster reef protective layer and ecological dike can also prevent the sediment from being carried away, slow down the loss of marine mud, and help ensure the stability of the tidal flat, thus achieving the effect of stabilizing the tidal flat.

[0014] 2. The water storage area provides a more stable growth environment for plant seedlings and biological nutrients during the low tide period, which is more conducive to the growth of plant seedlings. Moreover, the biological nutrients built on the ecological embankment can provide nutrients for the growth of mangroves after they die, which helps to improve the survival rate of plants. For example, when algae die or fall off, they will be decomposed into inorganic nutrients, thereby increasing the nutrient content in the soil and water, which is conducive to mangrove plants obtaining the nutrients they need for growth.

[0015] 3. Optimize the marine ecological environment and build a natural micro-ecosystem: First, the materials used in the protective structure are mainly wooden piles and oyster reefs, which will not have an adverse impact on the marine environment and marine life; second, the construction of ecological dikes can attract more marine plankton to form a micro-ecosystem, and when the tide recedes, the death of some organisms can become nutrients for mangrove growth without easily causing biodiversity; finally, the formation of a micro-ecosystem can further improve the stability of the ecological dike, enhance its ability to resist extreme weather such as typhoons, and form a natural symbiotic relationship with mangroves, which is conducive to mutual promotion of growth and reproduction.

[0016] 4. Simple structure, reduced construction cost and difficulty: The protective structure is mainly in the form of wooden piles and dikes, which is easy to construct, reducing construction costs. Moreover, it does not need to be dismantled and recycled later, reducing labor costs. In addition, as the ecosystem gradually forms, the role of human-assisted restoration for the growth of mangroves gradually weakens, which can reduce some maintenance costs.

[0017] Preferably, as an improvement, the target elevation in S1 is the filling of the area to be repaired with marine mud, and the thickness of the filling marine mud is such that the mudflat surface of the area to be repaired is 5-10 cm below the high tide line.

[0018] Beneficial effects: Raising the target elevation of the shoreline and tidal flats is conducive to constructing suitable mangrove tidal flats and improving the survival rate of mangroves; the thickness of the sea mud filling is such that the tidal flat surface of the area to be restored is 5-10cm below the high tide line, which facilitates the provision of a suitable thickness of mud and sand for mangrove planting, improves the survival rate of planted seedlings, accelerates the establishment and restoration of mangrove ecosystems, and the thickness of the sea mud filling is such that it just covers the tidal flat surface at high tide and exposes the tidal flat surface at low tide, which facilitates the periodic flooding-receding environment for mangrove seedlings.

[0019] Preferably, as an improvement, the wooden pile protection structure in S2 has at least three layers.

[0020] Beneficial effects: By placing wooden stakes on the outermost layer of suitable afforestation land and adjusting the distribution of the stakes, the effects of wave dissipation and mud stabilization can be achieved simultaneously.

[0021] Preferably, as an improvement, the oyster reef protective layer in S3 is formed by stacking oyster reefs to create a breakwater.

[0022] Beneficial effects: Setting up the oyster reef protective layer in the form of a breakwater can buffer the impact of large high tides and waves, effectively reducing the damage of sea waves to mangroves.

[0023] Preferably, as an improvement, different mangrove species are selected according to different tidal zones to create mixed forests, which are planted in an irregular clump pattern.

[0024] Preferably, as an improvement, a tidal ditch is constructed between the embankment and the suitable afforestation area.

[0025] Beneficial effects: On the one hand, it facilitates the irrigation of mangroves on the embankment side by seawater through tidal channels; on the other hand, it can also help to disperse and reduce the impact of waves on the seaward side.

[0026] Preferably, as an improvement, the ecological dike includes a protective wall, and the area between the protective wall and the oyster reef breakwater layer constitutes a water storage area, with the terrain of the water storage area gradually decreasing along the seaward side.

[0027] Beneficial effects:

[0028] 1. It can ensure that the water storage area can store water for a long time, so that the seawater is not easily lost after the tide recedes. Part of the stored seawater can be used by the mangroves, and the other part is conducive to the survival of biological nutrients in the ecological dam.

[0029] 2. When the high tide recedes, the oyster reef breakwater can prevent the loss of silt and sand in the suitable forest land. A small portion of the silt and sand that passes through the oyster reef breakwater will be intercepted by the protective wall and deposited there, thus forming a natural dike between the protective wall and the oyster reef protective layer. This natural dike can, on the one hand, strengthen the protective wall and the oyster reef protective layer, so that the two protective layers gradually connect into a whole, improving the ability to resist strong winds and waves and extreme weather. On the other hand, it can better stabilize the mud and the dike, thus forming a "growth dike".

[0030] 3. As mangrove seedlings grow, they can better adapt to the tidal flat environment. Therefore, when silt gradually accumulates at the protective wall and compresses the water storage area, it will not affect the plants in the suitable afforestation area. Moreover, as the water storage space of the water storage area gradually decreases, it can further avoid the problem of excessive growth of aquatic plants and plankton in the area, which is conducive to the gradual formation of a balanced natural ecological zone, thereby realizing the mutual promotion between mangroves and this ecological zone.

[0031] Preferably, as an improvement, a wave-dissipating layer is stacked above the protective wall, the wave-dissipating layer being higher than the oyster reef protective layer, and the porosity between the wave-dissipating layers being natural porosity.

[0032] Beneficial effects:

[0033] 1. Installing a wave-damping layer above the protective wall can reduce the scouring effect of wind and waves on the mudflats inside the protective wall, and also facilitate the entry of sea waves into the water storage area through the pores or the top of the wave-damping layer to replenish the water storage area.

[0034] 2. Setting the wave-dissipating layer higher than the oyster reef protection layer allows dead algae and plankton to be washed into suitable afforestation areas by the impact of waves or during high tide.

[0035] 3. The wave-damping layer also filters out floating debris such as garbage, making it easier to collect and contain such debris within the protective wall, which facilitates subsequent manual cleaning.

[0036] Preferably, as an improvement, the planting area is set on the side of the protective wall near the water storage area, and the planting area includes several trenches, in which biological nutrients are placed.

[0037] Beneficial effects: It can provide an attachment base for the biological nutrients of plants and reduce the erosion of plants by waves and tides.

[0038] Preferably, as an improvement, biological nutrients include algae or aquatic plants.

[0039] Beneficial effects: Dead algae settle and accumulate in suitable mangrove areas, and after decomposition, they can provide rich nutrients for the mangrove ecosystem, especially elements such as nitrogen and phosphorus. In addition, algal remains can stabilize sediments and reduce the risk of seedling root erosion, thus promoting seedling rooting and growth. Attached Figure Description

[0040] Figure 1 is a cross-sectional view of the afforestation structure in Embodiment 1 of the present invention.

[0041] Figure 2 is a cross-sectional view of the suitable afforestation land construction structure in Embodiment 3 of the present invention. Detailed Implementation

[0042] The following detailed description illustrates the specific implementation method:

[0043] The reference numerals in the accompanying drawings include: 1. Embankment, 2. Coastal side, 3. Tidal ditch, 4. Suitable afforestation land, 5. Wooden pile protective structure, 6. Oyster reef protective layer, 7. Ecological dam, 71. Water storage area, 72. Protective slope.

[0044] An embodiment of the present invention was tested at the newly built mangrove ecological restoration project base on the seaside of the National Museum of China - Shenzhen, to systematically restore the mangrove ecosystem on a scale of 2 hectares, in order to create a model for ecological restoration of land reclamation.

[0045] Example 1

[0046] A method for constructing suitable mangrove tidal flats for afforestation based on elevation, as shown in Figure 1, includes the following restoration steps:

[0047] S1. Construct 4 suitable afforestation sites on the tidal flats, based on the target elevation:

[0048] In this embodiment, marine mud is filled into the area to be restored (existing tidal flat) to determine the target elevation. The thickness of the marine mud filling is such that the tidal flat surface of the area to be restored is 5-10 cm below the high tide line. This facilitates the provision of a suitable thickness of mud and sand for mangrove planting, improves the survival rate of planted seedlings, accelerates the establishment and restoration of the mangrove ecosystem, and ensures that the mud filling thickness just covers the tidal flat surface during high tide and exposes it during low tide, thus providing a periodic flood-receding environment for mangrove seedlings.

[0049] S2. Construct a primary protective structure, and build a timber pile protective structure 5 on the seaside side 2 of the suitable afforestation land 4:

[0050] The wooden stake protection structure 5 shall be set up with at least three layers, all of which shall be made of pine stakes. The driving depth of the pine stakes shall be 2 / 3 of the length of the pine stakes. Specifically, the diameter of the pine stakes shall be 12cm, and the lengths shall be 4m, 5m and 6m. Four pine stakes shall be set up per meter, with an interval of 15cm between adjacent pine stakes. The pine stakes shall be used as the first layer of protection structure for the suitable mangrove forest land 4, so as to play a role in stabilizing the mud and reducing waves.

[0051] S3. Construct a secondary protective structure, building an oyster reef protective layer 6 between the perimeter of the suitable forest land 4 and the wooden pile protective structure 5:

[0052] Specifically, the oyster reef protective layer 6 is formed by densely stacking oyster reefs to create a breakwater. The porosity of the breakwater is natural porosity, and the height of the breakwater is slightly higher than the lowest elevation of the tidal flat. In this embodiment, the height of the breakwater is specifically set to 2.3m. The breakwater, as the second protective structure of the suitable afforestation land 4, is located outside the suitable afforestation land 4 to define the scope of the suitable afforestation land 4. It is mainly used to eliminate the erosion of the tidal flat by sea waves, protect the tidal flat, and further play a role in wave dissipation and mud stabilization.

[0053] S4. Construct ecological dam 7 between the primary protection structure and the secondary protection structure:

[0054] A water storage area 71 is formed between the ecological dike 7 and the secondary protective structure, and several planting areas (not shown in the figure) are also set on the ecological dike 7. The planting areas are used to fill the planting biological nutrients. Specifically, in this embodiment, the ecological dike 7 is a protective wall. The protective wall is made of shellfish shells such as oyster shells, mud, silt, adhesives, etc. The protective wall has a good water-blocking effect. The area between the protective wall and the oyster reef protective layer 6 forms a water storage area 71, and the terrain of the water storage area 71 gradually decreases along the seaward side 2. In order to reduce the loss of marine mud on the outside of the ecological dike 7 and improve the stability of the ecological dike 7, oyster reefs can also be piled on the outside of the ecological dike 7 to form a protective slope 72.

[0055] In this embodiment, the protective wall is located between the wooden pile protective structure 5 and the oyster reef protective layer 6. It can form the third protective structure of the suitable afforestation land 4, further playing a role in wave dissipation and dike reinforcement, and can also serve as an independent ecological attachment base to attract marine shellfish, planktonic plants and animals, microorganisms, etc. to form an ecological zone. Specifically, the planting area is set on the side of the protective wall near the water storage area 71. Several trenches are set in the planting area, and biological nutrients are placed in the trenches. Biological nutrients include algae or aquatic plants that are beneficial to the growth of mangroves. In actual use, the seedlings of algae and aquatic plants can be placed in the trenches, and the openings of the trenches can be surrounded by netting to allow them to reproduce and grow on the protective wall.

[0056] During high tide, seawater successively submerges the protective wall and oyster reef protective layer 6, replenishing the water storage area 71. Simultaneously, seawater enters the suitable planting area 4 to irrigate mangrove seedlings. Furthermore, during high tide, the ecological dike 7 is submerged, attracting marine plankton, shellfish, and other organisms to reside on it, forming a micro-ecosystem with the organisms in the planting area. When the tide recedes, some marine life dies, while others in the water storage area 71 continue to survive. When waves occur or the tide rises again, the dead organisms are pushed to the suitable planting area 4 by the impact of the waves, thus becoming nutrients for the mangrove seedlings. Additionally, some of the seawater stored in the water storage area 71 after low tide can enter the suitable planting area 4, providing a moist living environment for the mangrove seedlings and improving their early survival rate. When waves occur, seawater is continuously pushed into the water storage area 71, replenishing it.

[0057] S5. Mangrove Planting and Restoration: Different mangrove species are selected based on different tidal zones to create mixed forests, planted in irregular clusters. Specifically, different tree species and planting methods are determined based on different climate zones, soil composition, tidal flat height, salinity, and the degree of wind and wave influence, prioritizing superior native tree species. While ensuring the survival and growth rates of tree species, emphasis is placed on improving the biodiversity of the forest stands. This embodiment combines the analysis of existing mangrove ecological restoration cases in the Qianhai area. After the construction of suitable afforestation area 4 in this region, which is in the mid-to-low tidal zone, the selected tree species for mangrove restoration include: Kandelia candel, Rhizophora stylosa, Avicennia marina, Avicennia marina, Prunus armeniaca, and Rhizophora stylosa.

[0058] Based on the construction of suitable mangrove forest land 4, this invention can also optimize the marine ecological environment and construct a natural micro-ecosystem: First, the materials used in the protective structure are mainly wooden piles and oyster reefs, which will not have an adverse impact on the marine environment and marine life; second, the construction of ecological dike 7 can attract more marine plankton to form a micro-ecosystem, and when the tide recedes, the death of some organisms can become nutrients for mangrove growth without easily causing biodiversity; finally, after the formation of the micro-ecosystem, it can further improve the stability of ecological dike 7, improve its ability to resist extreme weather such as typhoons, and form a natural symbiotic relationship with mangroves, which is conducive to mutual promotion of growth and reproduction.

[0059] Example 2

[0060] The difference between this embodiment and Embodiment 1 is that it also provides another ecological dike 7 structure, in which a wave-dissipating layer (not shown in the figure) is densely stacked above the protective wall. The porosity between the wave-dissipating layers is natural porosity, and the wave-dissipating layer is higher than the oyster reef protective layer 6. Specifically, the wave-dissipating layer is made of oyster reef. First, setting a wave-dissipating layer above the protective wall can further reduce the scouring effect of large winds and waves on the mudflats inside the protective wall, and also facilitates the entry of sea waves into the water storage area 71 through the pores or the top of the wave-dissipating layer to replenish the water storage area 71. Second, setting the wave-dissipating layer higher than the oyster reef protective layer 6 is beneficial for washing dead algae, plankton, etc. into the suitable forest land 4 under the impact of sea waves or during high tide. Finally, the wave-dissipating layer can also filter floating debris such as garbage, making it easier to collect and contain some floating garbage inside the protective wall, which is beneficial for subsequent manual cleaning.

[0061] Example 3

[0062] The difference between this embodiment and embodiments one and two is that, as shown in Figure 2, it also includes constructing a tidal ditch 3 between the embankment 1 and the suitable afforestation land 4, and piling up stones or oyster reefs between the tidal ditch 3 and the suitable afforestation land 4 to reduce the loss of silt around the tidal ditch 3.

[0063] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for constructing suitable mangrove tidal flat afforestation land based on elevation, characterized in that, The process includes the following steps: S1. Constructing suitable afforestation land on the tidal flats: Constructing suitable afforestation land according to the target elevation; S2. Constructing a primary protective structure: Constructing a timber pile protective structure on the seaward side of the suitable afforestation land; S3. Constructing a secondary protective structure: Constructing an oyster reef protective layer between the outer perimeter of the suitable afforestation land and the timber pile protective structure; the oyster reef protective layer is formed by piling up oyster reefs to form a breakwater; S4. Constructing an ecological dam: Constructing an ecological dam between the primary and secondary protective structures, the ecological dam including a protective wall, the area between the protective wall and the oyster reef breakwater layer forming a water storage area, and the terrain of the water storage area gradually decreases along the seaward side, and several planting areas are also set on the ecological dam, the planting areas being filled with planting biological nutrients; the planting areas are set on the side of the protective wall near the water storage area, the planting areas including several trenches, and biological nutrients are placed in the trenches; biological nutrients include algae or aquatic plants; the process is as follows: at high tide, seawater successively submerges the protective structure. The wall and oyster reef protective layer replenish the water storage area, while seawater enters the suitable planting area to irrigate mangrove seedlings. During high tide, the ecological dike is submerged by seawater, attracting marine plankton and shellfish to reside on the dike and form a micro-ecosystem with the organisms in the planting area. When the tide recedes, some marine organisms die, while others in the water storage area can continue to survive. When waves occur or the tide rises again, the dead organisms are pushed to the suitable planting area by the impact of the waves, thus becoming nutrients for the growth of mangrove seedlings. In addition, some of the seawater stored in the water storage area after the tide recedes can also enter the suitable planting area, thus providing a moist living environment for mangrove seedlings and improving the early survival rate of mangroves. When waves occur, seawater will be continuously pushed into the water storage area, thus replenishing the water storage area. A wave-dissipating layer is also stacked above the protective wall, which is higher than the oyster reef protective layer, and the porosity between the wave-dissipating layers is natural porosity.

2. The method for constructing suitable mangrove tidal flats for afforestation based on elevation according to claim 1, characterized in that: The target elevation in S1 is the area to be repaired filled with marine mud, and the thickness of the marine mud filling is such that the mudflat surface of the area to be repaired is 5-10 cm below the high tide line.

3. The method for constructing suitable mangrove tidal flats for afforestation based on elevation according to claim 2, characterized in that: The wooden pile protective structure in S2 shall be at least three layers deep.

4. The method for constructing suitable mangrove tidal flats for afforestation based on elevation according to claim 3, characterized in that: Different mangrove species are selected based on different tidal zones to create mixed forests, which are then planted in irregular clusters.

5. The method for constructing suitable mangrove tidal flats for afforestation based on elevation according to claim 4, characterized in that: Construct tidal channels between the embankment and suitable afforestation land.

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